AI Trajectory

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "KMSANReasoning": "",
  "NeedsKMSAN": false,
  "Reasoning": "The patch modifies tdx_handle_ept_violation() in arch/x86/kvm/vmx/tdx.c, which handles Secure EPT (SEPT) violations for Intel TDX guests. Intel TDX host support requires physical hardware (Intel 4th/5th Gen Xeon or newer) with TDX enabled in firmware/BIOS and an authenticated Intel TDX SEAM module loaded into SEAMRR. Without this specialized physical hardware, X86_FEATURE_TDX_HOST_PLATFORM is disabled, enable_tdx is set to false, and TDX VMs (KVM_X86_TDX_VM) cannot be created. Because TDX host virtualization is not emulated in standard QEMU or supported in GCE virtualized environments, the modified code is structurally unreachable for fuzzing.",
  "WorthFuzzing": false
}

null

{
  "PatchDiff": "commit 26884ebf5c307baaa88be680f4d5a79f248b260b\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Sat Sep 26 00:00:47 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c\nindex 7173ef3fc398e..eb82f739a7c04 100644\n--- a/arch/x86/kvm/vmx/tdx.c\n+++ b/arch/x86/kvm/vmx/tdx.c\n@@ -1938,8 +1938,8 @@ static int tdx_handle_ept_violation(struct kvm_vcpu *vcpu)\n \t\tif (tdx_is_sept_violation_unexpected_pending(vcpu)) {\n \t\t\tpr_warn(\"Guest access before accepting 0x%llx on vCPU %d\\n\",\n \t\t\t\tgpa, vcpu-\u003evcpu_id);\n-\t\t\tkvm_vm_dead(vcpu-\u003ekvm);\n-\t\t\treturn -EIO;\n+\t\t\tkvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);\n+\t\t\treturn 1;\n \t\t}\n \t\t/*\n \t\t * Always treat SEPT violations as write faults.  Ignore the\n"
}

core

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch modifies tdx_handle_ept_violation() in arch/x86/kvm/vmx/tdx.c, which handles Secure EPT (SEPT) violations for Intel TDX guests. Intel TDX host support requires physical hardware (Intel 4th/5th Gen Xeon or newer) with TDX enabled in firmware/BIOS and an authenticated Intel TDX SEAM module loaded into SEAMRR. Without this specialized physical hardware, X86_FEATURE_TDX_HOST_PLATFORM is disabled, enable_tdx is set to false, and TDX VMs (KVM_X86_TDX_VM) cannot be created. Because TDX host virtualization is not emulated in standard QEMU or supported in GCE virtualized environments, the modified code is structurally unreachable for fuzzing.",
  "WorthFuzzing": false
}

You are an expert Linux kernel maintainer and security engineer.
Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller.

IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on internal assumptions. You must actively use your code access
tools to inspect the actual source code, callers, and surrounding context.

================================================================================
1. CORE TRIAGE PHILOSOPHY
================================================================================
The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs,
and newly triggered assertions introduced by the patch series.

- REACHABILITY IS THE PRIMARY GATE:
  Fuzzing can only discover bugs in code that can actually execute in standard virtualized
  environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap).
  If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed,
  regardless of whether it adds assertions or complex logic.

- DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS:
  Patch authors routinely label changes as "cleanups", "refactorings", or state
  "No functional change intended". Do NOT take these claims at face value.
  Code refactorings that rearrange logic, introduce helper functions, or alter state management
  in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs.
  If reachable executable code is modified or refactored, it MUST be fuzzed.

- NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED:
  When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON*, VM_WARN_ON*,
  BUG_ON*, lockdep_assert*) in reachable code paths, it enforces new or stricter invariants.
  Even if the author believes the invariant always holds, fuzzing is essential to verify whether
  an unusual sequence of operations can violate it.

================================================================================
2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA)
================================================================================
Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories:

- Non-kernel and non-executable changes:
  * Modifications to Documentation/, comments, or spelling fixes.
  * User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/)
    that do not affect the compiled kernel image (vmlinux) or kernel modules.
  * Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints
    that do not alter control flow or data structures.
  * Build system or Kconfig changes that do not alter compiled C logic.
- Structurally unreachable hardware:
  * Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed,
    ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU.
- Unreachable execution paths:
  * Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during
    physical PCI hot-unplug or manual sysfs driver unbinding.
  * Code paths exclusive to architectures other than the target architecture.

================================================================================
3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA)
================================================================================
Return WorthFuzzing=true whenever the patch touches reachable executable code, including:
- Core Subsystems:
  * Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/),
    BPF, scheduler, core networking, VFS, or syscall handling.
- Refactorings and Code Cleanups:
  * Any restructuring of reachable data structures, helper abstractions, or algorithm flows.
- Runtime Assertions and Defensive Checks:
  * Any introduction or alteration of assertions (WARN_ON*, VM_WARN_ON*, BUG_ON*, etc.) in reachable paths.
- Reachable Drivers and Protocols:
  * Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.).

================================================================================
4. EXTRACTING FocusSymbols (PREVENTING DILUTION)
================================================================================
When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer:

- AVOID UBIQUITOUS LIFECYCLE HOT-PATHS:
  Do NOT list generic, ubiquitous functions called by almost every program in the corpus
  (including, but not limited to: general memory allocators and deallocators, page fault
  and trap handlers, or core synchronization primitives; this is not an exhaustive list).
  Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused",
  which severely dilutes fuzzing effort away from the actual changes.

- TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS:
  List functions that specifically implement the logic being added or altered, or direct API entrypoints
  for the subsystem feature under review.

- HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h):
  Compiler-inlined static functions (such as static inlines in mm/*.h or include/linux/*.h) lack
  distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters.
  If the changes are primarily in static inline helpers, identify non-static, feature-specific caller
  functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers).

================================================================================
5. IDENTIFYING EnableConfigs
================================================================================
Identify any specific CONFIG_ options required to properly compile and reach the modified code:
- Inspect Kconfig files and #ifdef guards; do not make assumptions.
- Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed.
- Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4").
Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit 26884ebf5c307baaa88be680f4d5a79f248b260b
Author: syz-cluster <triage@syzkaller.com>
Date:   Sat Sep 26 00:00:47 2026 +0000

    syz-cluster: applied patch under review

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 7173ef3fc398e..eb82f739a7c04 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1938,8 +1938,8 @@ static int tdx_handle_ept_violation(struct kvm_vcpu *vcpu)
 		if (tdx_is_sept_violation_unexpected_pending(vcpu)) {
 			pr_warn("Guest access before accepting 0x%llx on vCPU %d\n",
 				gpa, vcpu->vcpu_id);
-			kvm_vm_dead(vcpu->kvm);
-			return -EIO;
+			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
+			return 1;
 		}
 		/*
 		 * Always treat SEPT violations as write faults.  Ignore the

gemini-3.8-flash

null

null

							input: 2954
							output: 45
							thoughts: 703
						

**Analyzing a TDX Patch for Fuzzing Suitability**

Okay, so this patch touches `arch/x86/kvm/vmx/tdx.c`. My immediate thought is, "TDX, right, Intel's Trust Domain Extensions for KVM." I need to understand this change within the broader context of TDX support in KVM. Let's look at the diff. Hmm, it looks like a TDX EPT violation handler is being modified. Specifically, it seems like a guest access before accepting an address is being handled differently. It's switching from `kvm_vm_dead` and returning `-EIO` to `kvm_make_request(KVM_REQ_TRIPLE_FAULT)` and returning `1`. This is critical.

But before I dig into the specifics of this change, I need to zoom out. Is this code even *fuzzable*? Is it reachable in a standard environment? The text keeps mentioning "reachability" as a primary concern for fuzzing. If this modified code is structurally unreachable, it's a dead end. I need to be sure that this code can be executed in a standard virtualized environment (QEMU, GCE). I need to check the hardware requirements!

This gets me thinking. Does TDX require *physical* TDX hardware? Emerald Rapids or Sapphire Rapids with TDX enabled at the BIOS/firmware level? Can TDX be emulated? Can KVM even *initialize* TDX features without the underlying hardware? I know some hardware features are emulated, but TDX is a fairly complex security feature, so I need to check the Kconfig, and surrounding code in `arch/x86/kvm/vmx/tdx.c`. This is the first gate. I need to be sure that I can actually get here before I dig into this code in detail.

{
  "File": "arch/x86/kvm/vmx/tdx.c",
  "FirstLine": 1925,
  "LineCount": 40
}

{
  "Contents": "1925:\t\t\treturn false;\n1926:\t\n1927:\t\treturn !(eq \u0026 EPT_VIOLATION_PROT_MASK);\n1928:\t}\n1929:\t\n1930:\tstatic int tdx_handle_ept_violation(struct kvm_vcpu *vcpu)\n1931:\t{\n1932:\t\tunsigned long exit_qual;\n1933:\t\tgpa_t gpa = to_tdx(vcpu)-\u003eexit_gpa;\n1934:\t\tbool local_retry = false;\n1935:\t\tint ret;\n1936:\t\n1937:\t\tif (vt_is_tdx_private_gpa(vcpu-\u003ekvm, gpa)) {\n1938:\t\t\tif (tdx_is_sept_violation_unexpected_pending(vcpu)) {\n1939:\t\t\t\tpr_warn(\"Guest access before accepting 0x%llx on vCPU %d\\n\",\n1940:\t\t\t\t\tgpa, vcpu-\u003evcpu_id);\n1941:\t\t\t\tkvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);\n1942:\t\t\t\treturn 1;\n1943:\t\t\t}\n1944:\t\t\t/*\n1945:\t\t\t * Always treat SEPT violations as write faults.  Ignore the\n1946:\t\t\t * EXIT_QUALIFICATION reported by TDX-SEAM for SEPT violations.\n1947:\t\t\t * TD private pages are always RWX in the SEPT tables,\n1948:\t\t\t * i.e. they're always mapped writable.  Just as importantly,\n1949:\t\t\t * treating SEPT violations as write faults is necessary to\n1950:\t\t\t * avoid COW allocations, which will cause TDAUGPAGE failures\n1951:\t\t\t * due to aliasing a single HPA to multiple GPAs.\n1952:\t\t\t */\n1953:\t\t\texit_qual = EPT_VIOLATION_ACC_WRITE;\n1954:\t\n1955:\t\t\t/* Only private GPA triggers zero-step mitigation */\n1956:\t\t\tlocal_retry = true;\n1957:\t\t} else {\n1958:\t\t\texit_qual = vt_get_exit_qual(vcpu);\n1959:\t\t\t/*\n1960:\t\t\t * EPT violation due to instruction fetch should never be\n1961:\t\t\t * triggered from shared memory in TDX guest.  If such EPT\n1962:\t\t\t * violation occurs, treat it as broken hardware.\n1963:\t\t\t */\n1964:\t\t\tif (KVM_BUG_ON(exit_qual \u0026 EPT_VIOLATION_ACC_INSTR, vcpu-\u003ekvm))\n"
}

gemini-3.8-flash

null

null

							input: 4788
							output: 23
							thoughts: 38
						

Okay, here's my understanding, formatted as requested:

**Investigating TDX Initialization in KVM**

Alright, let's dive into how Trusted Domain Extensions (TDX) is enabled and initialized within the KVM environment. I need to get a clear picture of the setup. First, let's use `grep` to pinpoint the critical function: `tdx_handle_ept_violation`. That function is probably the heart of how KVM deals with the Extended Page Table (EPT) violations that are core to TDX operation, so understanding its call graph is key. By grepping for it, I can see what triggers these violations and, by extension, how TDX is actively involved in the system. The next step will be to analyze those call sites.

{
  "Expression": "tdx_handle_ept_violation"
}

{
  "Output": "arch/x86/kvm/vmx/tdx.c=1919=static inline bool tdx_is_sept_violation_unexpected_pending(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/tdx.c-1929-\narch/x86/kvm/vmx/tdx.c:1930:static int tdx_handle_ept_violation(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/tdx.c-1931-{\n--\narch/x86/kvm/vmx/tdx.c=2047=int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)\n--\narch/x86/kvm/vmx/tdx.c-2122-\tcase EXIT_REASON_EPT_VIOLATION:\narch/x86/kvm/vmx/tdx.c:2123:\t\treturn tdx_handle_ept_violation(vcpu);\narch/x86/kvm/vmx/tdx.c-2124-\tcase EXIT_REASON_OTHER_SMI:\n"
}

gemini-3.8-flash

null

null

							input: 5327
							output: 20
							thoughts: 39
						

Here's a summary of my thought process, as requested:

**Diving into TDX Guest Exits**

Alright, let's get down to brass tacks. I need to understand how these TDX guests actually *exit*. My focus is immediately on `tdx_handle_exit` – that's the key function handling the transitions. My next question is: *What* calls this function? And further, what does the TDX environment setup look like that leads to these exits? I need to understand the control flow and the broader context of TDX guest operations. I'll start digging into the call graph and the initialization code to map this out clearly.

{
  "Expression": "tdx_handle_exit"
}

{
  "Output": "arch/x86/kvm/vmx/main.c=952=static int vt_handle_exit(struct kvm_vcpu *vcpu,\n--\narch/x86/kvm/vmx/main.c-958-\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c:959:\t\tret = tdx_handle_exit(vcpu, fastpath);\narch/x86/kvm/vmx/main.c-960-\telse\n--\narch/x86/kvm/vmx/tdx.c=935=static __always_inline union vmx_exit_reason tdx_to_vmx_exit_reason(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/tdx.c-960-\t\t/*\narch/x86/kvm/vmx/tdx.c:961:\t\t * Defer KVM_BUG_ON() until tdx_handle_exit() because this is in\narch/x86/kvm/vmx/tdx.c-962-\t\t * non-instrumentable code with interrupts disabled.\n--\narch/x86/kvm/vmx/tdx.c=1151=static int tdx_handle_exception_nmi(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/tdx.c-1156-\t * Machine checks are handled by handle_exception_irqoff(), or by\narch/x86/kvm/vmx/tdx.c:1157:\t * tdx_handle_exit() with TDX_NON_RECOVERABLE set if a #MC occurs on\narch/x86/kvm/vmx/tdx.c-1158-\t * VM-Entry.  NMIs are handled by tdx_vcpu_enter_exit().\n--\narch/x86/kvm/vmx/tdx.c=2033=int tdx_complete_emulated_msr(struct kvm_vcpu *vcpu, int err)\n--\narch/x86/kvm/vmx/tdx.c-2046-\narch/x86/kvm/vmx/tdx.c:2047:int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)\narch/x86/kvm/vmx/tdx.c-2048-{\n--\narch/x86/kvm/vmx/x86_ops.h=142=void tdx_vcpu_put(struct kvm_vcpu *vcpu);\narch/x86/kvm/vmx/x86_ops.h:143:int tdx_handle_exit(struct kvm_vcpu *vcpu,\narch/x86/kvm/vmx/x86_ops.h-144-\t\tenum exit_fastpath_completion fastpath);\n"
}

gemini-3.8-flash

null

null

							input: 6289
							output: 20
							thoughts: 74
						

Okay, let's break this down.

**Investigating the Transition to a TD vCPU**

Right, so I'm looking at this code and I see `is_td_vcpu(vcpu)` triggering `tdx_handle_exit(vcpu, fastpath)`. My mind immediately jumps to the question: *How* does a virtual CPU (vcpu) get designated as a "TD vcpu"? And, by extension, how does the whole virtual machine (VM) transition into being a TDX VM? This has a direct impact on the way that this function is run.

My immediate next step is to examine the logical pathways of `is_td_vcpu` and `is_td`, the functions that I assume are key to understanding the state transitions or identification of TD related configuration. I need to understand what conditions or flags are being checked to determine if a vcpu is operating within a Trusted Domain. This is central to understanding the flow of execution here. Let's dig in and see what those functions are doing.

{
  "Expression": "is_td_vcpu"
}

{
  "Output": "arch/x86/kvm/vmx/common.h=65=static __always_inline bool is_td(struct kvm *kvm)\n--\narch/x86/kvm/vmx/common.h-69-\narch/x86/kvm/vmx/common.h:70:static __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/common.h-71-{\n--\narch/x86/kvm/vmx/common.h=77=static __always_inline bool is_td(struct kvm *kvm) { return false; }\narch/x86/kvm/vmx/common.h:78:static __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu) { return false; }\narch/x86/kvm/vmx/common.h-79-\n--\narch/x86/kvm/vmx/common.h=102=static __always_inline unsigned long vt_get_exit_qual(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/common.h-106-\tif (!kvm_register_test_and_mark_available(vcpu, VCPU_REG_EXIT_INFO_1) \u0026\u0026\narch/x86/kvm/vmx/common.h:107:\t    !WARN_ON_ONCE(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/common.h-108-\t\tvt-\u003eexit_qualification = vmcs_readl(EXIT_QUALIFICATION);\n--\narch/x86/kvm/vmx/common.h=113=static __always_inline u32 vt_get_intr_info(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/common.h-117-\tif (!kvm_register_test_and_mark_available(vcpu, VCPU_REG_EXIT_INFO_2) \u0026\u0026\narch/x86/kvm/vmx/common.h:118:\t    !WARN_ON_ONCE(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/common.h-119-\t\tvt-\u003eexit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);\n--\narch/x86/kvm/vmx/main.c=78=static int vt_vcpu_create(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-79-{\narch/x86/kvm/vmx/main.c:80:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-81-\t\treturn tdx_vcpu_create(vcpu);\n--\narch/x86/kvm/vmx/main.c=86=static void vt_vcpu_free(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-87-{\narch/x86/kvm/vmx/main.c:88:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-89-\t\ttdx_vcpu_free(vcpu);\n--\narch/x86/kvm/vmx/main.c=96=static void vt_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)\narch/x86/kvm/vmx/main.c-97-{\narch/x86/kvm/vmx/main.c:98:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-99-\t\ttdx_vcpu_reset(vcpu, init_event);\n--\narch/x86/kvm/vmx/main.c=106=static void vt_vcpu_load(struct kvm_vcpu *vcpu, int cpu)\narch/x86/kvm/vmx/main.c-107-{\narch/x86/kvm/vmx/main.c:108:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-109-\t\ttdx_vcpu_load(vcpu, cpu);\n--\narch/x86/kvm/vmx/main.c=116=static void vt_update_cpu_dirty_logging(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-121-\t */\narch/x86/kvm/vmx/main.c:122:\tif (WARN_ON_ONCE(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/main.c-123-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=128=static void vt_prepare_switch_to_guest(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-129-{\narch/x86/kvm/vmx/main.c:130:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-131-\t\ttdx_prepare_switch_to_guest(vcpu);\n--\narch/x86/kvm/vmx/main.c=138=static void vt_vcpu_put(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-139-{\narch/x86/kvm/vmx/main.c:140:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-141-\t\ttdx_vcpu_put(vcpu);\n--\narch/x86/kvm/vmx/main.c=148=static bool vt_vcpu_needs_initialization(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-149-{\narch/x86/kvm/vmx/main.c:150:\treturn is_td_vcpu(vcpu) \u0026\u0026\narch/x86/kvm/vmx/main.c-151-\t       tdx_vcpu_needs_initialization(vcpu);\n--\narch/x86/kvm/vmx/main.c=154=static fastpath_t vt_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)\narch/x86/kvm/vmx/main.c-155-{\narch/x86/kvm/vmx/main.c:156:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-157-\t\treturn tdx_vcpu_run(vcpu, run_flags);\n--\narch/x86/kvm/vmx/main.c=162=static bool vt_unhandleable_emulation_required(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-163-{\narch/x86/kvm/vmx/main.c:164:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-165-\t\tWARN_ON_ONCE(to_vt(vcpu)-\u003eemulation_required);\n--\narch/x86/kvm/vmx/main.c=172=static int vt_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)\narch/x86/kvm/vmx/main.c-173-{\narch/x86/kvm/vmx/main.c:174:\tif (unlikely(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/main.c-175-\t\treturn tdx_set_msr(vcpu, msr_info);\n--\narch/x86/kvm/vmx/main.c=192=static int vt_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)\narch/x86/kvm/vmx/main.c-193-{\narch/x86/kvm/vmx/main.c:194:\tif (unlikely(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/main.c-195-\t\treturn tdx_get_msr(vcpu, msr_info);\n--\narch/x86/kvm/vmx/main.c=200=static void vt_recalc_intercepts(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-207-\t */\narch/x86/kvm/vmx/main.c:208:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-209-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=214=static int vt_complete_emulated_msr(struct kvm_vcpu *vcpu, int err)\narch/x86/kvm/vmx/main.c-215-{\narch/x86/kvm/vmx/main.c:216:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-217-\t\treturn tdx_complete_emulated_msr(vcpu, err);\n--\narch/x86/kvm/vmx/main.c=223=static int vt_smi_allowed(struct kvm_vcpu *vcpu, bool for_injection)\narch/x86/kvm/vmx/main.c-224-{\narch/x86/kvm/vmx/main.c:225:\tif (KVM_BUG_ON(is_td_vcpu(vcpu), vcpu-\u003ekvm))\narch/x86/kvm/vmx/main.c-226-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=231=static int vt_enter_smm(struct kvm_vcpu *vcpu, union kvm_smram *smram)\narch/x86/kvm/vmx/main.c-232-{\narch/x86/kvm/vmx/main.c:233:\tif (KVM_BUG_ON(is_td_vcpu(vcpu), vcpu-\u003ekvm))\narch/x86/kvm/vmx/main.c-234-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=239=static int vt_leave_smm(struct kvm_vcpu *vcpu, const union kvm_smram *smram)\narch/x86/kvm/vmx/main.c-240-{\narch/x86/kvm/vmx/main.c:241:\tif (KVM_BUG_ON(is_td_vcpu(vcpu), vcpu-\u003ekvm))\narch/x86/kvm/vmx/main.c-242-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=247=static void vt_enable_smi_window(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-248-{\narch/x86/kvm/vmx/main.c:249:\tif (KVM_BUG_ON(is_td_vcpu(vcpu), vcpu-\u003ekvm))\narch/x86/kvm/vmx/main.c-250-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=257=static int vt_check_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type,\n--\narch/x86/kvm/vmx/main.c-266-\t */\narch/x86/kvm/vmx/main.c:267:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-268-\t\treturn X86EMUL_RETRY_INSTR;\n--\narch/x86/kvm/vmx/main.c=273=static bool vt_apic_init_signal_blocked(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-278-\t */\narch/x86/kvm/vmx/main.c:279:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-280-\t\treturn true;\n--\narch/x86/kvm/vmx/main.c=285=static void vt_set_virtual_apic_mode(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-287-\t/* Only x2APIC mode is supported for TD. */\narch/x86/kvm/vmx/main.c:288:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-289-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=294=static void vt_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)\narch/x86/kvm/vmx/main.c-295-{\narch/x86/kvm/vmx/main.c:296:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-297-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=302=static int vt_sync_pir_to_irr(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-303-{\narch/x86/kvm/vmx/main.c:304:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-305-\t\treturn -1;\n--\narch/x86/kvm/vmx/main.c=310=static void vt_deliver_interrupt(struct kvm_lapic *apic, int delivery_mode,\n--\narch/x86/kvm/vmx/main.c-312-{\narch/x86/kvm/vmx/main.c:313:\tif (is_td_vcpu(apic-\u003evcpu)) {\narch/x86/kvm/vmx/main.c-314-\t\ttdx_deliver_interrupt(apic, delivery_mode, trig_mode,\n--\narch/x86/kvm/vmx/main.c=322=static void vt_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-323-{\narch/x86/kvm/vmx/main.c:324:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-325-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=330=static void vt_update_exception_bitmap(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-331-{\narch/x86/kvm/vmx/main.c:332:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-333-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=338=static u64 vt_get_segment_base(struct kvm_vcpu *vcpu, int seg)\narch/x86/kvm/vmx/main.c-339-{\narch/x86/kvm/vmx/main.c:340:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-341-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=346=static void vt_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var,\n--\narch/x86/kvm/vmx/main.c-348-{\narch/x86/kvm/vmx/main.c:349:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-350-\t\tmemset(var, 0, sizeof(*var));\n--\narch/x86/kvm/vmx/main.c=357=static void vt_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var,\n--\narch/x86/kvm/vmx/main.c-359-{\narch/x86/kvm/vmx/main.c:360:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-361-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=366=static int vt_get_cpl(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-367-{\narch/x86/kvm/vmx/main.c:368:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-369-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=374=static int vt_get_cpl_no_cache(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-375-{\narch/x86/kvm/vmx/main.c:376:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-377-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=382=static void vt_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)\narch/x86/kvm/vmx/main.c-383-{\narch/x86/kvm/vmx/main.c:384:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-385-\t\t*db = 0;\n--\narch/x86/kvm/vmx/main.c=393=static bool vt_is_valid_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)\narch/x86/kvm/vmx/main.c-394-{\narch/x86/kvm/vmx/main.c:395:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-396-\t\treturn true;\n--\narch/x86/kvm/vmx/main.c=401=static void vt_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)\narch/x86/kvm/vmx/main.c-402-{\narch/x86/kvm/vmx/main.c:403:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-404-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=409=static bool vt_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)\narch/x86/kvm/vmx/main.c-410-{\narch/x86/kvm/vmx/main.c:411:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-412-\t\treturn true;\n--\narch/x86/kvm/vmx/main.c=417=static void vt_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)\narch/x86/kvm/vmx/main.c-418-{\narch/x86/kvm/vmx/main.c:419:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-420-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=425=static int vt_set_efer(struct kvm_vcpu *vcpu, u64 efer)\narch/x86/kvm/vmx/main.c-426-{\narch/x86/kvm/vmx/main.c:427:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-428-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=433=static void vt_get_idt(struct kvm_vcpu *vcpu, struct desc_ptr *dt)\narch/x86/kvm/vmx/main.c-434-{\narch/x86/kvm/vmx/main.c:435:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-436-\t\tmemset(dt, 0, sizeof(*dt));\n--\narch/x86/kvm/vmx/main.c=443=static void vt_set_idt(struct kvm_vcpu *vcpu, struct desc_ptr *dt)\narch/x86/kvm/vmx/main.c-444-{\narch/x86/kvm/vmx/main.c:445:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-446-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=451=static void vt_get_gdt(struct kvm_vcpu *vcpu, struct desc_ptr *dt)\narch/x86/kvm/vmx/main.c-452-{\narch/x86/kvm/vmx/main.c:453:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-454-\t\tmemset(dt, 0, sizeof(*dt));\n--\narch/x86/kvm/vmx/main.c=461=static void vt_set_gdt(struct kvm_vcpu *vcpu, struct desc_ptr *dt)\narch/x86/kvm/vmx/main.c-462-{\narch/x86/kvm/vmx/main.c:463:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-464-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=469=static void vt_set_dr7(struct kvm_vcpu *vcpu, unsigned long val)\narch/x86/kvm/vmx/main.c-470-{\narch/x86/kvm/vmx/main.c:471:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-472-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=477=static void vt_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-483-\t */\narch/x86/kvm/vmx/main.c:484:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-485-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=490=static void vt_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)\narch/x86/kvm/vmx/main.c-491-{\narch/x86/kvm/vmx/main.c:492:\tif (WARN_ON_ONCE(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/main.c-493-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=498=static unsigned long vt_get_rflags(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-499-{\narch/x86/kvm/vmx/main.c:500:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-501-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=506=static void vt_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)\narch/x86/kvm/vmx/main.c-507-{\narch/x86/kvm/vmx/main.c:508:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-509-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=514=static bool vt_get_if_flag(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-515-{\narch/x86/kvm/vmx/main.c:516:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-517-\t\treturn false;\n--\narch/x86/kvm/vmx/main.c=522=static void vt_flush_tlb_all(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-523-{\narch/x86/kvm/vmx/main.c:524:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-525-\t\ttdx_flush_tlb_all(vcpu);\n--\narch/x86/kvm/vmx/main.c=532=static void vt_flush_tlb_current(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-533-{\narch/x86/kvm/vmx/main.c:534:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-535-\t\ttdx_flush_tlb_current(vcpu);\n--\narch/x86/kvm/vmx/main.c=542=static void vt_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr, bool *full)\narch/x86/kvm/vmx/main.c-543-{\narch/x86/kvm/vmx/main.c:544:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-545-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=550=static void vt_flush_tlb_guest(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-551-{\narch/x86/kvm/vmx/main.c:552:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-553-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=558=static void vt_inject_nmi(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-559-{\narch/x86/kvm/vmx/main.c:560:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-561-\t\ttdx_inject_nmi(vcpu);\n--\narch/x86/kvm/vmx/main.c=568=static int vt_nmi_allowed(struct kvm_vcpu *vcpu, bool for_injection)\n--\narch/x86/kvm/vmx/main.c-573-\t */\narch/x86/kvm/vmx/main.c:574:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-575-\t\treturn true;\n--\narch/x86/kvm/vmx/main.c=580=static bool vt_get_nmi_mask(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-585-\t */\narch/x86/kvm/vmx/main.c:586:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-587-\t\treturn false;\n--\narch/x86/kvm/vmx/main.c=592=static void vt_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)\narch/x86/kvm/vmx/main.c-593-{\narch/x86/kvm/vmx/main.c:594:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-595-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=600=static void vt_enable_nmi_window(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-602-\t/* Refer to the comments in tdx_inject_nmi(). */\narch/x86/kvm/vmx/main.c:603:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-604-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=609=static void vt_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,\n--\narch/x86/kvm/vmx/main.c-611-{\narch/x86/kvm/vmx/main.c:612:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-613-\t\ttdx_load_mmu_pgd(vcpu, root_hpa, pgd_level);\n--\narch/x86/kvm/vmx/main.c=620=static void vt_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)\narch/x86/kvm/vmx/main.c-621-{\narch/x86/kvm/vmx/main.c:622:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-623-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=628=static u32 vt_get_interrupt_shadow(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-629-{\narch/x86/kvm/vmx/main.c:630:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-631-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=636=static void vt_patch_hypercall(struct kvm_vcpu *vcpu,\n--\narch/x86/kvm/vmx/main.c-642-\t */\narch/x86/kvm/vmx/main.c:643:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-644-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=649=static void vt_inject_irq(struct kvm_vcpu *vcpu, bool reinjected)\narch/x86/kvm/vmx/main.c-650-{\narch/x86/kvm/vmx/main.c:651:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-652-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=657=static void vt_inject_exception(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-658-{\narch/x86/kvm/vmx/main.c:659:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-660-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=665=static void vt_cancel_injection(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-666-{\narch/x86/kvm/vmx/main.c:667:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-668-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=673=static int vt_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection)\narch/x86/kvm/vmx/main.c-674-{\narch/x86/kvm/vmx/main.c:675:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-676-\t\treturn tdx_interrupt_allowed(vcpu);\n--\narch/x86/kvm/vmx/main.c=681=static void vt_enable_irq_window(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-682-{\narch/x86/kvm/vmx/main.c:683:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-684-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=689=static void vt_get_entry_info(struct kvm_vcpu *vcpu, u32 *intr_info, u32 *error_code)\n--\narch/x86/kvm/vmx/main.c-693-\narch/x86/kvm/vmx/main.c:694:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-695-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=700=static void vt_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,\n--\narch/x86/kvm/vmx/main.c-702-{\narch/x86/kvm/vmx/main.c:703:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-704-\t\ttdx_get_exit_info(vcpu, reason, info1, info2, intr_info,\n--\narch/x86/kvm/vmx/main.c=712=static void vt_update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)\narch/x86/kvm/vmx/main.c-713-{\narch/x86/kvm/vmx/main.c:714:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-715-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=720=static void vt_set_apic_access_page_addr(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-721-{\narch/x86/kvm/vmx/main.c:722:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-723-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=728=static void vt_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-729-{\narch/x86/kvm/vmx/main.c:730:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-731-\t\tKVM_BUG_ON(!kvm_vcpu_apicv_active(vcpu), vcpu-\u003ekvm);\n--\narch/x86/kvm/vmx/main.c=738=static void vt_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)\narch/x86/kvm/vmx/main.c-739-{\narch/x86/kvm/vmx/main.c:740:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-741-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=770=static u64 vt_get_l2_tsc_offset(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-772-\t/* TDX doesn't support L2 guest at the moment. */\narch/x86/kvm/vmx/main.c:773:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-774-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=779=static u64 vt_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-781-\t/* TDX doesn't support L2 guest at the moment. */\narch/x86/kvm/vmx/main.c:782:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-783-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=788=static void vt_write_tsc_offset(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-790-\t/* In TDX, tsc offset can't be changed. */\narch/x86/kvm/vmx/main.c:791:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-792-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=797=static void vt_write_tsc_multiplier(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-799-\t/* In TDX, tsc multiplier can't be changed. */\narch/x86/kvm/vmx/main.c:800:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-801-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=806=static int vt_set_hv_timer(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc,\n--\narch/x86/kvm/vmx/main.c-809-\t/* VMX-preemption timer isn't available for TDX. */\narch/x86/kvm/vmx/main.c:810:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-811-\t\treturn -EINVAL;\n--\narch/x86/kvm/vmx/main.c=816=static void vt_cancel_hv_timer(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-818-\t/* VMX-preemption timer can't be set.  See vt_set_hv_timer(). */\narch/x86/kvm/vmx/main.c:819:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-820-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=825=static void vt_setup_mce(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-826-{\narch/x86/kvm/vmx/main.c:827:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-828-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=841=static int vt_vcpu_mem_enc_ioctl(struct kvm_vcpu *vcpu, void __user *argp)\narch/x86/kvm/vmx/main.c-842-{\narch/x86/kvm/vmx/main.c:843:\tif (!is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-844-\t\treturn -EINVAL;\n--\narch/x86/kvm/vmx/main.c=849=static int vt_vcpu_mem_enc_unlocked_ioctl(struct kvm_vcpu *vcpu, void __user *argp)\narch/x86/kvm/vmx/main.c-850-{\narch/x86/kvm/vmx/main.c:851:\tif (!is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-852-\t\treturn -EINVAL;\n--\narch/x86/kvm/vmx/main.c=952=static int vt_handle_exit(struct kvm_vcpu *vcpu,\n--\narch/x86/kvm/vmx/main.c-957-#ifdef CONFIG_KVM_INTEL_TDX\narch/x86/kvm/vmx/main.c:958:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-959-\t\tret = tdx_handle_exit(vcpu, fastpath);\n--\narch/x86/kvm/vmx/pmu_intel.c=40=static struct lbr_desc *vcpu_to_lbr_desc(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/pmu_intel.c-41-{\narch/x86/kvm/vmx/pmu_intel.c:42:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/pmu_intel.c-43-\t\treturn NULL;\n--\narch/x86/kvm/vmx/pmu_intel.c=48=static struct x86_pmu_lbr *vcpu_to_lbr_records(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/pmu_intel.c-49-{\narch/x86/kvm/vmx/pmu_intel.c:50:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/pmu_intel.c-51-\t\treturn NULL;\n--\narch/x86/kvm/vmx/pmu_intel.c=149=static bool intel_pmu_lbr_is_compatible(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/pmu_intel.c-150-{\narch/x86/kvm/vmx/pmu_intel.c:151:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/pmu_intel.c-152-\t\treturn false;\n--\narch/x86/kvm/vmx/pmu_intel.c=157=bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/pmu_intel.c-158-{\narch/x86/kvm/vmx/pmu_intel.c:159:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/pmu_intel.c-160-\t\treturn false;\n--\narch/x86/kvm/vmx/posted_intr.c=211=static bool vt_needs_pi_wakeup(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/posted_intr.c-220-\t */\narch/x86/kvm/vmx/posted_intr.c:221:\treturn (vmx_can_use_ipiv(vcpu) \u0026\u0026 !is_td_vcpu(vcpu)) ||\narch/x86/kvm/vmx/posted_intr.c-222-\t\tvt_can_use_vtd_pi(vcpu-\u003ekvm);\n--\narch/x86/kvm/vmx/posted_intr.c=225=void vt_vcpu_pi_put(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/posted_intr.c-244-\tif (!vcpu-\u003epreempted \u0026\u0026 kvm_vcpu_is_blocking(vcpu) \u0026\u0026\narch/x86/kvm/vmx/posted_intr.c:245:\t    ((is_td_vcpu(vcpu) \u0026\u0026 tdx_interrupt_allowed(vcpu)) ||\narch/x86/kvm/vmx/posted_intr.c:246:\t     (!is_td_vcpu(vcpu) \u0026\u0026 !vmx_interrupt_blocked(vcpu))))\narch/x86/kvm/vmx/posted_intr.c-247-\t\tpi_enable_wakeup_handler(vcpu);\n"
}

gemini-3.8-flash

null

null

							input: 19034
							output: 42
							thoughts: 58
						

Here's my thinking process:

**Diving into the `is_td` Definition**

Okay, so I need to understand how `is_td` is defined. The hint tells me to look in `arch/x86/kvm/vmx/common.h`. Right, that's where I'd expect to find something fundamental related to VMX and common to the x86 architecture. I'm going to jump to lines 55-80 of that file. That should give me the context I need. Likely, the definition of `is_td` is either there, or, importantly, I'll find its dependencies in that range. I'm expecting this to be a crucial element, perhaps a macro, function, or something similar, that directly influences how a specific aspect of the VMX operation is handled.

{
  "File": "arch/x86/kvm/vmx/common.h",
  "FirstLine": 55,
  "LineCount": 35
}

{
  "Contents": "  55:\t\n  56:\t#ifdef CONFIG_X86_64\n  57:\t\tu64\t\tmsr_host_kernel_gs_base;\n  58:\t#endif\n  59:\t};\n  60:\t\n  61:\tnoinstr void vt_handle_nmi(struct kvm_vcpu *vcpu);\n  62:\t\n  63:\t#ifdef CONFIG_KVM_INTEL_TDX\n  64:\t\n  65:\tstatic __always_inline bool is_td(struct kvm *kvm)\n  66:\t{\n  67:\t\treturn kvm-\u003earch.vm_type == KVM_X86_TDX_VM;\n  68:\t}\n  69:\t\n  70:\tstatic __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu)\n  71:\t{\n  72:\t\treturn is_td(vcpu-\u003ekvm);\n  73:\t}\n  74:\t\n  75:\t#else\n  76:\t\n  77:\tstatic __always_inline bool is_td(struct kvm *kvm) { return false; }\n  78:\tstatic __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu) { return false; }\n  79:\t\n  80:\t#endif\n  81:\t\n  82:\tstruct vcpu_vmx_tdx {\n  83:\t\tstruct kvm_vcpu vcpu;\n  84:\t\tstruct vcpu_vt vt;\n  85:\t};\n  86:\t\n  87:\tstatic __always_inline struct vcpu_vt *to_vt(struct kvm_vcpu *vcpu)\n  88:\t{\n  89:\t\treturn \u0026(container_of(vcpu, struct vcpu_vmx_tdx, vcpu)-\u003evt);\n"
}

gemini-3.8-flash

null

null

							input: 19805
							output: 25
							thoughts: 58
						

Okay, let's dive into this.

**Investigating the KVM_X86_TDX_VM Configuration**

Alright, I need to understand this `KVM_X86_TDX_VM` setting. The question I have right now is, precisely how is a virtual machine actually *created* with this `KVM_X86_TDX_VM` configuration? It's time to dig in and figure out the process. My immediate course of action is clear: I'm going to start with a grep command. Let's see what the codebase turns up when I search for the symbol `KVM_X86_TDX_VM`. Hopefully, that will lead me to some relevant code and documentation, shedding light on the mechanics of building a VM that leverages this feature. I anticipate it could relate to the hypervisor, or the guest configuration mechanism, or possibly even both. This grep should be a good starting point.

{
  "Expression": "KVM_X86_TDX_VM"
}

{
  "Output": "Documentation/virt/kvm/api.rst=9602=means the VM type with value @n is supported.  Possible values of @n are::\n--\nDocumentation/virt/kvm/api.rst-9608-  #define KVM_X86_SNP_VM\t4\nDocumentation/virt/kvm/api.rst:9609:  #define KVM_X86_TDX_VM\t5\nDocumentation/virt/kvm/api.rst-9610-\n--\nDocumentation/virt/kvm/x86/intel-tdx.rst=237=control flow is as follows:\n--\nDocumentation/virt/kvm/x86/intel-tdx.rst-240-\nDocumentation/virt/kvm/x86/intel-tdx.rst:241:   * KVM_CAP_VM_TYPES: Check if VM type is supported and if KVM_X86_TDX_VM\nDocumentation/virt/kvm/x86/intel-tdx.rst-242-     is supported.\n--\narch/x86/include/uapi/asm/kvm.h=927=struct kvm_hyperv_eventfd {\n--\narch/x86/include/uapi/asm/kvm.h-974-#define KVM_X86_SNP_VM\t\t4\narch/x86/include/uapi/asm/kvm.h:975:#define KVM_X86_TDX_VM\t\t5\narch/x86/include/uapi/asm/kvm.h-976-\n--\narch/x86/kvm/mmu.h=392=static inline bool kvm_has_mirrored_tdp(const struct kvm *kvm)\narch/x86/kvm/mmu.h-393-{\narch/x86/kvm/mmu.h:394:\treturn kvm-\u003earch.vm_type == KVM_X86_TDX_VM;\narch/x86/kvm/mmu.h-395-}\n--\narch/x86/kvm/mmu/page_track.c=189=static int kvm_enable_external_write_tracking(struct kvm *kvm)\n--\narch/x86/kvm/mmu/page_track.c-194-\narch/x86/kvm/mmu/page_track.c:195:\tif (kvm-\u003earch.vm_type == KVM_X86_TDX_VM)\narch/x86/kvm/mmu/page_track.c-196-\t\treturn -EOPNOTSUPP;\n--\narch/x86/kvm/vmx/common.h=65=static __always_inline bool is_td(struct kvm *kvm)\narch/x86/kvm/vmx/common.h-66-{\narch/x86/kvm/vmx/common.h:67:\treturn kvm-\u003earch.vm_type == KVM_X86_TDX_VM;\narch/x86/kvm/vmx/common.h-68-}\n--\narch/x86/kvm/vmx/main.c=1158=static int __init vt_init(void)\n--\narch/x86/kvm/vmx/main.c-1178-\t\t\t\t__alignof__(struct vcpu_tdx));\narch/x86/kvm/vmx/main.c:1179:\t\tkvm_caps.supported_vm_types |= BIT(KVM_X86_TDX_VM);\narch/x86/kvm/vmx/main.c-1180-\t}\n--\ntools/arch/x86/include/uapi/asm/kvm.h=927=struct kvm_hyperv_eventfd {\n--\ntools/arch/x86/include/uapi/asm/kvm.h-974-#define KVM_X86_SNP_VM\t\t4\ntools/arch/x86/include/uapi/asm/kvm.h:975:#define KVM_X86_TDX_VM\t\t5\ntools/arch/x86/include/uapi/asm/kvm.h-976-\n"
}

gemini-3.8-flash

null

null

							input: 21168
							output: 44
							thoughts: 36
						

Here's my take on the thought process, as requested:

**Diving into KVM/VMX Initialization**

Alright, let's get down to brass tacks. I'm focusing on the x86 architecture, specifically the KVM/VMX implementation. I'm going to head straight into `arch/x86/kvm/vmx/main.c`, and I'm particularly interested in what's happening around line 1170. I figure that's where the crucial virtual-machine extensions (VMX) initialization logic is likely to reside. I need to understand how the VMX-specific parts of the kernel are set up. I'm going to start by scrutinizing the `vt_init` function. Let's see how it bootstraps the Virtualization Technology.

{
  "File": "arch/x86/kvm/vmx/main.c",
  "FirstLine": 1155,
  "LineCount": 45
}

{
  "Contents": "1155:\t}\n1156:\tmodule_exit(vt_exit);\n1157:\t\n1158:\tstatic int __init vt_init(void)\n1159:\t{\n1160:\t\tunsigned vcpu_size, vcpu_align;\n1161:\t\tint r;\n1162:\t\n1163:\t\tr = vmx_init();\n1164:\t\tif (r)\n1165:\t\t\treturn r;\n1166:\t\n1167:\t\t/*\n1168:\t\t * TDX and VMX have different vCPU structures.  Calculate the\n1169:\t\t * maximum size/align so that kvm_init() can use the larger\n1170:\t\t * values to create the kmem_vcpu_cache.\n1171:\t\t */\n1172:\t\tvcpu_size = sizeof(struct vcpu_vmx);\n1173:\t\tvcpu_align = __alignof__(struct vcpu_vmx);\n1174:\t\tif (enable_tdx) {\n1175:\t\t\tvcpu_size = max_t(unsigned, vcpu_size,\n1176:\t\t\t\t\tsizeof(struct vcpu_tdx));\n1177:\t\t\tvcpu_align = max_t(unsigned, vcpu_align,\n1178:\t\t\t\t\t__alignof__(struct vcpu_tdx));\n1179:\t\t\tkvm_caps.supported_vm_types |= BIT(KVM_X86_TDX_VM);\n1180:\t\t}\n1181:\t\n1182:\t\t/*\n1183:\t\t * Common KVM initialization _must_ come last, after this, /dev/kvm is\n1184:\t\t * exposed to userspace!\n1185:\t\t */\n1186:\t\tr = kvm_init(vcpu_size, vcpu_align, THIS_MODULE);\n1187:\t\tif (r)\n1188:\t\t\tgoto err_kvm_init;\n1189:\t\n1190:\t\treturn 0;\n1191:\t\n1192:\terr_kvm_init:\n1193:\t\tvmx_exit();\n1194:\t\treturn r;\n1195:\t}\n1196:\tmodule_init(vt_init);\n"
}

gemini-3.8-flash

null

null

							input: 22028
							output: 18
							thoughts: 22
						

Here's my attempt at summarizing the thought process, tailored for an expert audience:

**Analyzing the TDX Enablement Logic**

Okay, let's dive into this `enable_tdx` variable. I need to understand its initialization and how it influences the TDX (Trust Domain Extensions) environment setup. Where exactly is this flag defined and modified? I need to trace its assignment. I'll need to check the relevant initialization code, likely related to the hypervisor, firmware, or guest configuration, depending on the context of this implementation. Understanding the propagation of `enable_tdx` will be key to identifying potential TDX availability or configuration issues. It’s critical to figure out if this is controlled by command-line arguments, environment variables, or some other mechanism. Knowing the source is the first step.

{
  "Expression": "enable_tdx"
}

{
  "Output": "arch/x86/kvm/vmx/main.c=21=static void vt_disable_virtualization_cpu(void)\n--\narch/x86/kvm/vmx/main.c-23-\t/* Note, TDX *and* VMX need to be disabled if TDX is enabled. */\narch/x86/kvm/vmx/main.c:24:\tif (enable_tdx)\narch/x86/kvm/vmx/main.c-25-\t\ttdx_disable_virtualization_cpu();\n--\narch/x86/kvm/vmx/main.c=29=static __init int vt_hardware_setup(void)\n--\narch/x86/kvm/vmx/main.c-36-\narch/x86/kvm/vmx/main.c:37:\treturn enable_tdx ? tdx_hardware_setup() : 0;\narch/x86/kvm/vmx/main.c-38-}\n--\narch/x86/kvm/vmx/main.c=40=static void vt_hardware_unsetup(void)\narch/x86/kvm/vmx/main.c-41-{\narch/x86/kvm/vmx/main.c:42:\tif (enable_tdx)\narch/x86/kvm/vmx/main.c-43-\t\ttdx_hardware_unsetup();\n--\narch/x86/kvm/vmx/main.c=1158=static int __init vt_init(void)\n--\narch/x86/kvm/vmx/main.c-1173-\tvcpu_align = __alignof__(struct vcpu_vmx);\narch/x86/kvm/vmx/main.c:1174:\tif (enable_tdx) {\narch/x86/kvm/vmx/main.c-1175-\t\tvcpu_size = max_t(unsigned, vcpu_size,\n--\narch/x86/kvm/vmx/tdx.c-55-\narch/x86/kvm/vmx/tdx.c:56:bool enable_tdx __ro_after_init;\narch/x86/kvm/vmx/tdx.c:57:module_param_named(tdx, enable_tdx, bool, 0444);\narch/x86/kvm/vmx/tdx.c-58-\n--\narch/x86/kvm/vmx/tdx.c=3476=int __init tdx_hardware_setup(void)\n--\narch/x86/kvm/vmx/tdx.c-3483-\narch/x86/kvm/vmx/tdx.c:3484:\tif (!enable_tdx)\narch/x86/kvm/vmx/tdx.c-3485-\t\treturn 0;\n--\narch/x86/kvm/vmx/tdx.c-3539-success_disable_tdx:\narch/x86/kvm/vmx/tdx.c:3540:\tenable_tdx = 0;\narch/x86/kvm/vmx/tdx.c-3541-\treturn 0;\n--\narch/x86/kvm/vmx/tdx.h=11=void tdx_hardware_unsetup(void);\narch/x86/kvm/vmx/tdx.h-12-\narch/x86/kvm/vmx/tdx.h:13:extern bool enable_tdx;\narch/x86/kvm/vmx/tdx.h-14-\n--\narch/x86/kvm/vmx/tdx.h=185=TDX_BUILD_TDVPS_ACCESSORS(64, STATE_NON_ARCH, state_non_arch);\n--\narch/x86/kvm/vmx/tdx.h-187-#else\narch/x86/kvm/vmx/tdx.h:188:#define enable_tdx\t0\narch/x86/kvm/vmx/tdx.h-189-\n"
}

gemini-3.8-flash

null

null

							input: 23318
							output: 45
							thoughts: 32
						

Okay, here's my take on those thoughts, tailored for an expert audience, and written as if they are my own internal monologue:

**Diving into TDX Hardware Setup**

Alright, time to dig into the `tdx_hardware_setup` function. Specifically, I'm going to head over to `arch/x86/kvm/vmx/tdx.c`. This is where the rubber meets the road for Intel's Trust Domain Extensions on the x86 architecture, so I need to understand what's happening at this low level. I want to see how the system is initializing the hardware and setting up the foundations for TDX operation within the VMX context. I need to refresh my understanding of the interactions between the hypervisor and the underlying hardware, looking specifically at the TDX extensions and how they're exposed and managed within the KVM environment. I'm hoping to get a clearer picture of the control flow and any potential areas of concern for security or performance. My primary interest is in understanding how this function contributes to setting up the trust domain environment and if there's any area that's worth my deep investigation.

{
  "File": "arch/x86/kvm/vmx/tdx.c",
  "FirstLine": 3476,
  "LineCount": 70
}

{
  "Contents": "3476:\tint __init tdx_hardware_setup(void)\n3477:\t{\n3478:\t\tint r, i;\n3479:\t\n3480:\t\t/* tdx_disable_virtualization_cpu() uses associated_tdvcpus. */\n3481:\t\tfor_each_possible_cpu(i)\n3482:\t\t\tINIT_LIST_HEAD(\u0026per_cpu(associated_tdvcpus, i));\n3483:\t\n3484:\t\tif (!enable_tdx)\n3485:\t\t\treturn 0;\n3486:\t\n3487:\t\tif (!enable_ept) {\n3488:\t\t\tpr_err(\"EPT is required for TDX\\n\");\n3489:\t\t\tgoto success_disable_tdx;\n3490:\t\t}\n3491:\t\n3492:\t\tif (!tdp_mmu_enabled || !enable_mmio_caching || !enable_ept_ad_bits) {\n3493:\t\t\tpr_err(\"TDP MMU and MMIO caching and EPT A/D bit is required for TDX\\n\");\n3494:\t\t\tgoto success_disable_tdx;\n3495:\t\t}\n3496:\t\n3497:\t\tif (!enable_apicv) {\n3498:\t\t\tpr_err(\"APICv is required for TDX\\n\");\n3499:\t\t\tgoto success_disable_tdx;\n3500:\t\t}\n3501:\t\n3502:\t\tif (!cpu_feature_enabled(X86_FEATURE_OSXSAVE)) {\n3503:\t\t\tpr_err(\"tdx: OSXSAVE is required for TDX\\n\");\n3504:\t\t\tgoto success_disable_tdx;\n3505:\t\t}\n3506:\t\n3507:\t\tif (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)) {\n3508:\t\t\tpr_err(\"TDX not supported by the host platform\\n\");\n3509:\t\t\tgoto success_disable_tdx;\n3510:\t\t}\n3511:\t\n3512:\t\tr = __tdx_hardware_setup();\n3513:\t\tif (r) {\n3514:\t\t\t/*\n3515:\t\t\t * Disable TDX only but don't fail to load module if the TDX\n3516:\t\t\t * module could not be loaded.  No need to print message saying\n3517:\t\t\t * \"module is not loaded\" because it was printed when the first\n3518:\t\t\t * SEAMCALL failed.  Don't bother unwinding the S-EPT hooks or\n3519:\t\t\t * vm_size, as kvm_x86_ops have already been finalized (and are\n3520:\t\t\t * intentionally not exported).  The S-EPT code is unreachable,\n3521:\t\t\t * and allocating a few more bytes per VM in a should-be-rare\n3522:\t\t\t * failure scenario is a non-issue.\n3523:\t\t\t */\n3524:\t\t\tif (r == -ENODEV)\n3525:\t\t\t\tgoto success_disable_tdx;\n3526:\t\n3527:\t\t\treturn r;\n3528:\t\t}\n3529:\t\n3530:\t\tKVM_SANITY_CHECK_VM_STRUCT_SIZE(kvm_tdx);\n3531:\t\n3532:\t\tvt_x86_ops.vm_size = max_t(unsigned int, vt_x86_ops.vm_size, sizeof(struct kvm_tdx));\n3533:\t\n3534:\t\tvt_x86_ops.set_external_spte = tdx_sept_set_private_spte;\n3535:\t\tvt_x86_ops.free_external_spt = tdx_sept_free_private_spt;\n3536:\t\tvt_x86_ops.protected_apic_has_interrupt = tdx_protected_apic_has_interrupt;\n3537:\t\treturn 0;\n3538:\t\n3539:\tsuccess_disable_tdx:\n3540:\t\tenable_tdx = 0;\n3541:\t\treturn 0;\n3542:\t}\n"
}

gemini-3.8-flash

null

null

							input: 24745
							output: 27
							thoughts: 251
						

**Analyzing TDX Host Platform Support**

Okay, let's dive into this code snippet, specifically lines 3507-3528. It looks like we're in the middle of a check related to TDX (Trust Domain Extensions) support during initialization. The first thing I see is a critical check: `if (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM))`. If that feature isn't supported by the host platform, we immediately bail out with an error. Makes perfect sense; no point in trying to enable something that the hardware doesn't offer. Then there's a call to `__tdx_hardware_setup()`, which I'd assume handles the low-level hardware configuration. If that fails with an `-ENODEV`, we still disable TDX gracefully. Otherwise we return the error. The key is in that `success_disable_tdx` label, where `enable_tdx` gets set to 0. Now, I see that this value of `enable_tdx` is significant because it's used later in `vt_init`, where the `KVM_X86_TDX_VM` bit is only set in `kvm_caps.supported_vm_types` if `enable_tdx` is non-zero. That's the crux of it - setting that bit controls whether TDX VMs are considered supported.

Wait, the code references `X86_FEATURE_TDX_HOST_PLATFORM`. What exactly *is* that? I'm going to do a quick search to understand what that flag represents. I know that the logic here is crucial for ensuring that we don't try to enable a feature that the underlying hardware doesn't support. This is a common and important practice to prevent potential issues or crashes.

{
  "Expression": "X86_FEATURE_TDX_HOST_PLATFORM"
}

{
  "Output": "arch/x86/include/asm/cpufeatures.h-200-#define X86_FEATURE_CDP_L3\t\t( 7*32+ 6) /* \"cdp_l3\" Code and Data Prioritization L3 */\narch/x86/include/asm/cpufeatures.h:201:#define X86_FEATURE_TDX_HOST_PLATFORM\t( 7*32+ 7) /* \"tdx_host_platform\" Platform supports being a TDX host */\narch/x86/include/asm/cpufeatures.h-202-#define X86_FEATURE_HW_PSTATE\t\t( 7*32+ 8) /* \"hw_pstate\" AMD HW-PState */\n--\narch/x86/kvm/vmx/tdx.c=3476=int __init tdx_hardware_setup(void)\n--\narch/x86/kvm/vmx/tdx.c-3506-\narch/x86/kvm/vmx/tdx.c:3507:\tif (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)) {\narch/x86/kvm/vmx/tdx.c-3508-\t\tpr_err(\"TDX not supported by the host platform\\n\");\n--\narch/x86/virt/vmx/tdx/tdx.c=1226=static __init int tdx_enable(void)\n--\narch/x86/virt/vmx/tdx/tdx.c-1230-\narch/x86/virt/vmx/tdx/tdx.c:1231:\tif (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)) {\narch/x86/virt/vmx/tdx/tdx.c-1232-\t\tpr_err(\"TDX not supported by the host platform\\n\");\n--\narch/x86/virt/vmx/tdx/tdx.c=1368=static bool paddr_is_tdx_private(unsigned long phys)\n--\narch/x86/virt/vmx/tdx/tdx.c-1374-\narch/x86/virt/vmx/tdx/tdx.c:1375:\tif (!boot_cpu_has(X86_FEATURE_TDX_HOST_PLATFORM))\narch/x86/virt/vmx/tdx/tdx.c-1376-\t\treturn false;\n--\narch/x86/virt/vmx/tdx/tdx.c=1531=void __init tdx_init(void)\n--\narch/x86/virt/vmx/tdx/tdx.c-1582-\narch/x86/virt/vmx/tdx/tdx.c:1583:\tsetup_force_cpu_cap(X86_FEATURE_TDX_HOST_PLATFORM);\narch/x86/virt/vmx/tdx/tdx.c-1584-\n--\ndrivers/virt/coco/tdx-host/tdx-host.c=17=static const struct x86_cpu_id tdx_host_ids[] = {\ndrivers/virt/coco/tdx-host/tdx-host.c:18:\tX86_MATCH_FEATURE(X86_FEATURE_TDX_HOST_PLATFORM, NULL),\ndrivers/virt/coco/tdx-host/tdx-host.c-19-\t{}\n--\ntools/arch/x86/include/asm/cpufeatures.h-190-#define X86_FEATURE_CDP_L3\t\t( 7*32+ 6) /* \"cdp_l3\" Code and Data Prioritization L3 */\ntools/arch/x86/include/asm/cpufeatures.h:191:#define X86_FEATURE_TDX_HOST_PLATFORM\t( 7*32+ 7) /* \"tdx_host_platform\" Platform supports being a TDX host */\ntools/arch/x86/include/asm/cpufeatures.h-192-#define X86_FEATURE_HW_PSTATE\t\t( 7*32+ 8) /* \"hw_pstate\" AMD HW-PState */\n"
}

gemini-3.8-flash

null

null

							input: 26488
							output: 47
							thoughts: 84
						

Here's my thought process, as requested:

**Investigating the Implementation of `setup_force_cpu_cap(X86_FEATURE_TDX_HOST_PLATFORM)`**

Okay, so I need to understand the impact of the function `setup_force_cpu_cap(X86_FEATURE_TDX_HOST_PLATFORM)`. My initial approach is to trace its calls within the codebase, specifically within `arch/x86/virt/vmx/tdx/tdx.c`. My instinct is that this function likely has a significant role in enabling or configuring TDX host platform features on x86 systems. I suspect that understanding *where* it's called will provide critical context on *why* it's called and the conditions under which it's invoked.

Now, I'll go ahead and check that source file, paying close attention to the area around line 1531. I'll read the code around that line with the intention of discovering the surrounding code's role in the system. I would assume that the call to this function will be relevant to enabling or handling TDX functionalities.

{
  "File": "arch/x86/virt/vmx/tdx/tdx.c",
  "FirstLine": 1530,
  "LineCount": 60
}

{
  "Contents": "1530:\t\n1531:\tvoid __init tdx_init(void)\n1532:\t{\n1533:\t\tu32 tdx_keyid_start, nr_tdx_keyids;\n1534:\t\tint err;\n1535:\t\n1536:\t\terr = record_keyid_partitioning(\u0026tdx_keyid_start, \u0026nr_tdx_keyids);\n1537:\t\tif (err)\n1538:\t\t\treturn;\n1539:\t\n1540:\t\tpr_info(\"BIOS enabled: private KeyID range [%u, %u)\\n\",\n1541:\t\t\t\ttdx_keyid_start, tdx_keyid_start + nr_tdx_keyids);\n1542:\t\n1543:\t\t/*\n1544:\t\t * The TDX module itself requires one 'global KeyID' to protect\n1545:\t\t * its metadata.  If there's only one TDX KeyID, there won't be\n1546:\t\t * any left for TDX guests thus there's no point to enable TDX\n1547:\t\t * at all.\n1548:\t\t */\n1549:\t\tif (nr_tdx_keyids \u003c 2) {\n1550:\t\t\tpr_err(\"initialization failed: too few private KeyIDs available.\\n\");\n1551:\t\t\treturn;\n1552:\t\t}\n1553:\t\n1554:\t\t/*\n1555:\t\t * At this point, hibernation_available() indicates whether or\n1556:\t\t * not hibernation support has been permanently disabled.\n1557:\t\t */\n1558:\t\tif (hibernation_available()) {\n1559:\t\t\tpr_err(\"initialization failed: Hibernation support is enabled\\n\");\n1560:\t\t\treturn;\n1561:\t\t}\n1562:\t\n1563:\t\terr = register_memory_notifier(\u0026tdx_memory_nb);\n1564:\t\tif (err) {\n1565:\t\t\tpr_err(\"initialization failed: register_memory_notifier() failed (%d)\\n\",\n1566:\t\t\t\t\terr);\n1567:\t\t\treturn;\n1568:\t\t}\n1569:\t\n1570:\t#if defined(CONFIG_ACPI) \u0026\u0026 defined(CONFIG_SUSPEND)\n1571:\t\tpr_info(\"Disable ACPI S3. Turn off TDX in the BIOS to use ACPI S3.\\n\");\n1572:\t\tacpi_suspend_lowlevel = NULL;\n1573:\t#endif\n1574:\t\n1575:\t\t/*\n1576:\t\t * Just use the first TDX KeyID as the 'global KeyID' and\n1577:\t\t * leave the rest for TDX guests.\n1578:\t\t */\n1579:\t\ttdx_global_keyid = tdx_keyid_start;\n1580:\t\ttdx_guest_keyid_start = tdx_keyid_start + 1;\n1581:\t\ttdx_nr_guest_keyids = nr_tdx_keyids - 1;\n1582:\t\n1583:\t\tsetup_force_cpu_cap(X86_FEATURE_TDX_HOST_PLATFORM);\n1584:\t\n1585:\t\tcheck_tdx_erratum();\n1586:\t}\n1587:\t\n1588:\tconst struct tdx_sys_info *tdx_get_sysinfo(void)\n1589:\t{\n"
}

gemini-3.8-flash

null

null

							input: 27786
							output: 47
							thoughts: 46
						

Here's my analysis of the provided text, summarized in the first person, assuming an expert user:

**Diving into the TDX Partitioning Logic**

Okay, let's take a closer look at `record_keyid_partitioning`. I need to understand how this is handled, and the first place I'm going to turn is the source code. Specifically, I'm going to open up `arch/x86/virt/vmx/tdx/tdx.c`. My focus is going to be dissecting the logic here.

{
  "File": "arch/x86/virt/vmx/tdx/tdx.c",
  "FirstLine": 1495,
  "LineCount": 40
}

{
  "Contents": "1495:\t\t */\n1496:\t\tif (is_tdx_memory(mn-\u003estart_pfn, mn-\u003estart_pfn + mn-\u003enr_pages))\n1497:\t\t\treturn NOTIFY_OK;\n1498:\t\n1499:\t\treturn NOTIFY_BAD;\n1500:\t}\n1501:\t\n1502:\tstatic struct notifier_block tdx_memory_nb = {\n1503:\t\t.notifier_call = tdx_memory_notifier,\n1504:\t};\n1505:\t\n1506:\tstatic void __init check_tdx_erratum(void)\n1507:\t{\n1508:\t\tu64 basic_msr;\n1509:\t\n1510:\t\t/*\n1511:\t\t * These CPUs have an erratum.  A partial write from non-TD\n1512:\t\t * software (e.g. via MOVNTI variants or UC/WC mapping) to TDX\n1513:\t\t * private memory poisons that memory, and a subsequent read of\n1514:\t\t * that memory triggers #MC.\n1515:\t\t */\n1516:\t\tswitch (boot_cpu_data.x86_vfm) {\n1517:\t\tcase INTEL_SAPPHIRERAPIDS_X:\n1518:\t\tcase INTEL_EMERALDRAPIDS_X:\n1519:\t\t\tsetup_force_cpu_bug(X86_BUG_TDX_PW_MCE);\n1520:\t\t}\n1521:\t\n1522:\t\t/*\n1523:\t\t * Some TDX-capable CPUs have an erratum where the current VMCS is\n1524:\t\t * cleared after calling into P-SEAMLDR.\n1525:\t\t */\n1526:\t\trdmsrq(MSR_IA32_VMX_BASIC, basic_msr);\n1527:\t\tif (!(basic_msr \u0026 VMX_BASIC_NO_SEAMRET_INVD_VMCS))\n1528:\t\t\tsetup_force_cpu_bug(X86_BUG_SEAMRET_INVD_VMCS);\n1529:\t}\n1530:\t\n1531:\tvoid __init tdx_init(void)\n1532:\t{\n1533:\t\tu32 tdx_keyid_start, nr_tdx_keyids;\n1534:\t\tint err;\n"
}

gemini-3.8-flash

null

null

							input: 28638
							output: 21
							thoughts: 13
						

Okay, here's my interpretation of "Let's see `record_keyid_partitioning`", summarized as though I, an expert in the field, am thinking it:

**Deconstructing `record_keyid_partitioning`**

Alright, the phrase "Let's see `record_keyid_partitioning`" immediately pulls my attention. This is likely about data organization. I’m zeroing in on this concept because of the `partitioning` aspect. So, we're talking about taking a dataset and dividing it into smaller, manageable chunks. The "record_keyid" element is crucial here. My immediate assumption is that we are using some sort of key or identifier associated with each record, the `record_keyid`, to *determine* how to partition the data. This could be based on a range of values within the key, a hash of the key, or some other calculated attribute derived from it. The goal is likely to improve query performance, simplify data management, or enhance scalability. My brain's already running through a list of potential approaches and trade-offs. What's the context? What kind of data are we dealing with? What are the access patterns? The specific implementation will hinge on these key factors. This feels like it might be an interesting problem to delve into.

{
  "Expression": "record_keyid_partitioning"
}

{
  "Output": "arch/x86/virt/vmx/tdx/tdx.c=1418=const char *tdx_dump_mce_info(struct mce *m)\n--\narch/x86/virt/vmx/tdx/tdx.c-1428-\narch/x86/virt/vmx/tdx/tdx.c:1429:static __init int record_keyid_partitioning(u32 *tdx_keyid_start,\narch/x86/virt/vmx/tdx/tdx.c-1430-\t\t\t\t\t    u32 *nr_tdx_keyids)\n--\narch/x86/virt/vmx/tdx/tdx.c=1531=void __init tdx_init(void)\n--\narch/x86/virt/vmx/tdx/tdx.c-1535-\narch/x86/virt/vmx/tdx/tdx.c:1536:\terr = record_keyid_partitioning(\u0026tdx_keyid_start, \u0026nr_tdx_keyids);\narch/x86/virt/vmx/tdx/tdx.c-1537-\tif (err)\n"
}

gemini-3.8-flash

null

null

							input: 29265
							output: 47
							thoughts: 13
						

Okay, here's my interpretation of that thought process, tailored for an expert audience, and written in the first person:

**Initial Assessment: Navigating the Landscape of Partitioning**

Alright, let's dive in. The task is to examine `record_keyid_partitioning`. Straight away, my mind's running through the implications. I'm thinking about the design choices, potential bottlenecks, and the overall strategy employed to segment and manage data based on `record_keyid`. Given my experience, I'm already anticipating questions: what are the underlying performance requirements this system targets? What data volume are we talking about, and how does the partitioning scheme scale? What are the implications for query performance, especially with complex joins and aggregations? And, crucially, are we optimizing for read performance, write performance, or a balance? I need to analyze how this strategy interacts with indexing and whether any sort of data skew is present. Let's see what we've got.

{
  "File": "arch/x86/virt/vmx/tdx/tdx.c",
  "FirstLine": 1428,
  "LineCount": 40
}

{
  "Contents": "1428:\t\n1429:\tstatic __init int record_keyid_partitioning(u32 *tdx_keyid_start,\n1430:\t\t\t\t\t\t    u32 *nr_tdx_keyids)\n1431:\t{\n1432:\t\tu32 _nr_mktme_keyids, _tdx_keyid_start, _nr_tdx_keyids;\n1433:\t\tstruct msr val;\n1434:\t\tint ret;\n1435:\t\n1436:\t\t/*\n1437:\t\t * IA32_MKTME_KEYID_PARTIONING:\n1438:\t\t *   Bit [31:0]:\tNumber of MKTME KeyIDs.\n1439:\t\t *   Bit [63:32]:\tNumber of TDX private KeyIDs.\n1440:\t\t */\n1441:\t\tret = rdmsrq_safe(MSR_IA32_MKTME_KEYID_PARTITIONING, \u0026val.q);\n1442:\t\t_nr_mktme_keyids = val.l;\n1443:\t\t_nr_tdx_keyids = val.h;\n1444:\t\tif (ret || !_nr_tdx_keyids)\n1445:\t\t\treturn -EINVAL;\n1446:\t\n1447:\t\t/* TDX KeyIDs start after the last MKTME KeyID. */\n1448:\t\t_tdx_keyid_start = _nr_mktme_keyids + 1;\n1449:\t\n1450:\t\t*tdx_keyid_start = _tdx_keyid_start;\n1451:\t\t*nr_tdx_keyids = _nr_tdx_keyids;\n1452:\t\n1453:\t\treturn 0;\n1454:\t}\n1455:\t\n1456:\tstatic bool is_tdx_memory(unsigned long start_pfn, unsigned long end_pfn)\n1457:\t{\n1458:\t\tstruct tdx_memblock *tmb;\n1459:\t\n1460:\t\t/*\n1461:\t\t * This check assumes that the start_pfn\u003c-\u003eend_pfn range does not\n1462:\t\t * cross multiple @tdx_memlist entries.  A single memory online\n1463:\t\t * event across multiple memblocks (from which @tdx_memlist\n1464:\t\t * entries are derived at the time of module initialization) is\n1465:\t\t * not possible.  This is because memory offline/online is done\n1466:\t\t * on granularity of 'struct memory_block', and the hotpluggable\n1467:\t\t * memory region (one memblock) must be multiple of memory_block.\n"
}

gemini-3.8-flash

null

null

							input: 30253
							output: 43
							thoughts: 64
						

Here's my summary, as if I were thinking these things:

**Digging into TDX and MKTME Integration**

Okay, first things first, that `MSR_IA32_MKTME_KEYID_PARTITIONING` MSR! I need to refresh my memory on the specifics of how that's used, especially in the context of TDX. And let's not forget SEAMCALL! How's that integrated? I need to understand the control flow.

Hold on, before I dive too deep into the MSRs, let's take a look at the initialization process. Let's see what `__tdx_hardware_setup()` in `arch/x86/kvm/vmx/tdx.c` is actually doing. That function is probably key to setting up the hardware environment, enabling TDX features, and potentially configuring MKTME for the guest. Understanding the setup sequence will give me a better foundation for analyzing the MSR interactions and the SEAMCALL usage later on. This will likely give me a clear picture of how MKTME keys are chosen and if any specific key ID is set up for the partition.

{
  "Expression": "__tdx_hardware_setup",
  "PathPrefix": "arch/x86/kvm/vmx/tdx.c"
}

{
  "Output": "arch/x86/kvm/vmx/tdx.c=3397=void tdx_hardware_unsetup(void)\n--\narch/x86/kvm/vmx/tdx.c-3401-\narch/x86/kvm/vmx/tdx.c:3402:static int __init __tdx_hardware_setup(void)\narch/x86/kvm/vmx/tdx.c-3403-{\n--\narch/x86/kvm/vmx/tdx.c=3476=int __init tdx_hardware_setup(void)\n--\narch/x86/kvm/vmx/tdx.c-3511-\narch/x86/kvm/vmx/tdx.c:3512:\tr = __tdx_hardware_setup();\narch/x86/kvm/vmx/tdx.c-3513-\tif (r) {\n"
}

gemini-3.8-flash

null

null

							input: 30866
							output: 45
							thoughts: 32
						

Okay, here's my interpretation of that thought process, tailored for an expert audience, and written in the first person:

**Diving into the TDX Hardware Setup**

Alright, time to dig in. I need to understand how the TDX hardware is initialized within the x86 KVM environment. Specifically, I'm heading straight for the `__tdx_hardware_setup` function within `arch/x86/kvm/vmx/tdx.c`. This is where the rubber meets the road, where the low-level interactions with the TDX-specific hardware features are likely handled. I'm expecting to find the key routines related to setting up the trust domain environment, configuring the secrets, validating the attestation mechanisms, and probably some crucial memory management related functions. I'll be looking to understand the order of operations, the dependencies between the steps, and, of course, any potential points of failure or areas where security assumptions are made. I'll need to pay close attention to the registers being set, the control structures being manipulated, and any hypervisor-specific adjustments necessary to make TDX work seamlessly within KVM. This should be an interesting exploration.

{
  "File": "arch/x86/kvm/vmx/tdx.c",
  "FirstLine": 3400,
  "LineCount": 60
}

{
  "Contents": "3400:\t}\n3401:\t\n3402:\tstatic int __init __tdx_hardware_setup(void)\n3403:\t{\n3404:\t\tconst struct tdx_sys_info_td_conf *td_conf;\n3405:\t\tint i;\n3406:\t\n3407:\t\tfor (i = 0; i \u003c ARRAY_SIZE(tdx_uret_msrs); i++) {\n3408:\t\t\t/*\n3409:\t\t\t * Check if MSRs (tdx_uret_msrs) can be saved/restored\n3410:\t\t\t * before returning to user space.\n3411:\t\t\t */\n3412:\t\t\ttdx_uret_msrs[i].slot = kvm_find_user_return_msr(tdx_uret_msrs[i].msr);\n3413:\t\t\tif (tdx_uret_msrs[i].slot == -1) {\n3414:\t\t\t\t/* If any MSR isn't supported, it is a KVM bug */\n3415:\t\t\t\tpr_err(\"MSR %x isn't included by kvm_find_user_return_msr\\n\",\n3416:\t\t\t\t\ttdx_uret_msrs[i].msr);\n3417:\t\t\t\treturn -EIO;\n3418:\t\t\t}\n3419:\t\t}\n3420:\t\n3421:\t\t/* Get TDX global information for later use */\n3422:\t\ttdx_sysinfo = tdx_get_sysinfo();\n3423:\t\tif (!tdx_sysinfo)\n3424:\t\t\treturn -ENODEV;\n3425:\t\n3426:\t\t/* Check TDX module and KVM capabilities */\n3427:\t\tif (!tdx_get_supported_attrs(\u0026tdx_sysinfo-\u003etd_conf) ||\n3428:\t\t    !tdx_get_supported_xfam(\u0026tdx_sysinfo-\u003etd_conf))\n3429:\t\t\treturn -EINVAL;\n3430:\t\n3431:\t\tif (!(tdx_sysinfo-\u003efeatures.tdx_features0 \u0026 MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM))\n3432:\t\t\treturn -EINVAL;\n3433:\t\n3434:\t\t/*\n3435:\t\t * TDX has its own limit of maximum vCPUs it can support for all\n3436:\t\t * TDX guests in addition to KVM_MAX_VCPUS.  Userspace needs to\n3437:\t\t * query TDX guest's maximum vCPUs by checking KVM_CAP_MAX_VCPU\n3438:\t\t * extension on per-VM basis.\n3439:\t\t *\n3440:\t\t * TDX module reports such limit via the MAX_VCPU_PER_TD global\n3441:\t\t * metadata.  Different modules may report different values.\n3442:\t\t * Some old module may also not support this metadata (in which\n3443:\t\t * case this limit is U16_MAX).\n3444:\t\t *\n3445:\t\t * In practice, the reported value reflects the maximum logical\n3446:\t\t * CPUs that ALL the platforms that the module supports can\n3447:\t\t * possibly have.\n3448:\t\t *\n3449:\t\t * Simply forwarding the MAX_VCPU_PER_TD to userspace could\n3450:\t\t * result in an unpredictable ABI.  KVM instead always advertise\n3451:\t\t * the number of logical CPUs the platform has as the maximum\n3452:\t\t * vCPUs for TDX guests.\n3453:\t\t *\n3454:\t\t * Make sure MAX_VCPU_PER_TD reported by TDX module is not\n3455:\t\t * smaller than the number of logical CPUs, otherwise KVM will\n3456:\t\t * report an unsupported value to userspace.\n3457:\t\t *\n3458:\t\t * Note, a platform with TDX enabled in the BIOS cannot support\n3459:\t\t * physical CPU hotplug, and TDX requires the BIOS has marked\n"
}

gemini-3.8-flash

null

null

							input: 32236
							output: 21
							thoughts: 98
						

Okay, let's break this down.

**Investigating the TDX System Information Retrieval**

Right, so I'm looking into how TDX system information is retrieved. The key function here is `tdx_get_sysinfo()`. My initial thought is, what does this function return? Ah, it returns a `tdx_sysinfo` structure, obviously. Now, the next logical question is where is that `tdx_sysinfo` structure actually *populated*? Is it during the TDX enablement process, maybe within `tdx_enable()`? Or, and this feels more likely given the context, is it happening within the `arch/x86/virt/vmx/tdx/tdx.c` file itself? Let's assume that it's in the latter, I should probably check the source code for the `tdx_get_sysinfo` function within that file to trace where it is initialized. Time to dive into the code.

{
  "Expression": "tdx_get_sysinfo"
}

{
  "Output": "arch/x86/include/asm/tdx.h=113=const char *tdx_dump_mce_info(struct mce *m);\narch/x86/include/asm/tdx.h:114:const struct tdx_sys_info *tdx_get_sysinfo(void);\narch/x86/include/asm/tdx.h-115-\n--\narch/x86/include/asm/tdx.h=182=static inline const char *tdx_dump_mce_info(struct mce *m) { return NULL; }\narch/x86/include/asm/tdx.h:183:static inline const struct tdx_sys_info *tdx_get_sysinfo(void) { return NULL; }\narch/x86/include/asm/tdx.h-184-static inline void tdx_sys_disable(void) { }\n--\narch/x86/kvm/vmx/tdx.c=3402=static int __init __tdx_hardware_setup(void)\n--\narch/x86/kvm/vmx/tdx.c-3421-\t/* Get TDX global information for later use */\narch/x86/kvm/vmx/tdx.c:3422:\ttdx_sysinfo = tdx_get_sysinfo();\narch/x86/kvm/vmx/tdx.c-3423-\tif (!tdx_sysinfo)\n--\narch/x86/virt/vmx/tdx/tdx.c=1531=void __init tdx_init(void)\n--\narch/x86/virt/vmx/tdx/tdx.c-1587-\narch/x86/virt/vmx/tdx/tdx.c:1588:const struct tdx_sys_info *tdx_get_sysinfo(void)\narch/x86/virt/vmx/tdx/tdx.c-1589-{\n--\narch/x86/virt/vmx/tdx/tdx.c-1594-}\narch/x86/virt/vmx/tdx/tdx.c:1595:EXPORT_SYMBOL_FOR_MODULES(tdx_get_sysinfo, \"kvm-intel,tdx-host\");\narch/x86/virt/vmx/tdx/tdx.c-1596-\n--\ndrivers/virt/coco/tdx-host/tdx-host.c=23=static ssize_t version_show(struct device *dev, struct device_attribute *attr,\n--\ndrivers/virt/coco/tdx-host/tdx-host.c-25-{\ndrivers/virt/coco/tdx-host/tdx-host.c:26:\tconst struct tdx_sys_info *tdx_sysinfo = tdx_get_sysinfo();\ndrivers/virt/coco/tdx-host/tdx-host.c-27-\tconst struct tdx_sys_info_version *ver;\n--\ndrivers/virt/coco/tdx-host/tdx-host.c=100=static bool supports_runtime_update(void)\ndrivers/virt/coco/tdx-host/tdx-host.c-101-{\ndrivers/virt/coco/tdx-host/tdx-host.c:102:\tconst struct tdx_sys_info *sysinfo = tdx_get_sysinfo();\ndrivers/virt/coco/tdx-host/tdx-host.c-103-\n--\ndrivers/virt/coco/tdx-host/tdx-host.c=216=static int __init tdx_host_init(void)\ndrivers/virt/coco/tdx-host/tdx-host.c-217-{\ndrivers/virt/coco/tdx-host/tdx-host.c:218:\tif (!x86_match_cpu(tdx_host_ids) || !tdx_get_sysinfo())\ndrivers/virt/coco/tdx-host/tdx-host.c-219-\t\treturn -ENODEV;\n"
}

gemini-3.8-flash

null

null

							input: 33599
							output: 47
							thoughts: 35
						

Here's my take on the thought process:

**Diving into the TDX System Information Retrieval**

Okay, time to get my hands dirty. I need to understand how we're actually retrieving system information within the TDX environment. Let's start with the low-level stuff. My first stop is definitely going to be the `tdx_get_sysinfo` implementation. I know it's located within `arch/x86/virt/vmx/tdx/tdx.c`. That file is where the core TDX functionality for x86 systems resides, so the system information retrieval will most certainly be in there, or linked from there. I'm expecting this will contain the crucial details I need. Let's see what we can find.

{
  "File": "arch/x86/virt/vmx/tdx/tdx.c",
  "FirstLine": 1585,
  "LineCount": 20
}

{
  "Contents": "1585:\t\tcheck_tdx_erratum();\n1586:\t}\n1587:\t\n1588:\tconst struct tdx_sys_info *tdx_get_sysinfo(void)\n1589:\t{\n1590:\t\tif (!tdx_module_state.initialized)\n1591:\t\t\treturn NULL;\n1592:\t\n1593:\t\treturn (const struct tdx_sys_info *)\u0026tdx_sysinfo;\n1594:\t}\n1595:\tEXPORT_SYMBOL_FOR_MODULES(tdx_get_sysinfo, \"kvm-intel,tdx-host\");\n1596:\t\n1597:\tu32 tdx_get_nr_guest_keyids(void)\n1598:\t{\n1599:\t\treturn tdx_nr_guest_keyids;\n1600:\t}\n1601:\tEXPORT_SYMBOL_FOR_KVM(tdx_get_nr_guest_keyids);\n1602:\t\n1603:\tint tdx_guest_keyid_alloc(void)\n1604:\t{\n"
}

gemini-3.8-flash

null

null

							input: 34152
							output: 20
							thoughts: 52
						

Here's my analysis of the situation:

**Investigating a NULL Return from tdx_get_sysinfo**

Okay, so `tdx_get_sysinfo` is returning NULL. The first thing that jumps out at me, based on my understanding of this code, is the conditional: it returns NULL if `!tdx_module_state.initialized`. Right, so the crucial question is: where does `tdx_module_state.initialized` actually get set to `true`? I need to trace the initialization sequence. I'm going to have to dive into the code that manages `tdx_module_state` and figure out the exact point that `initialized` transitions from `false` to `true`. This likely involves looking at the module initialization functions or any setup routines that directly manipulate that state variable. I need to understand the lifecycle of this module.

{
  "Expression": "tdx_module_state"
}

{
  "Output": "arch/x86/virt/vmx/tdx/tdx.c-48-\narch/x86/virt/vmx/tdx/tdx.c:49:struct tdx_module_state {\narch/x86/virt/vmx/tdx/tdx.c-50-\tbool initialized;\n--\narch/x86/virt/vmx/tdx/tdx.c-54-\narch/x86/virt/vmx/tdx/tdx.c:55:static struct tdx_module_state tdx_module_state;\narch/x86/virt/vmx/tdx/tdx.c-56-static u32 tdx_global_keyid __ro_after_init;\n--\narch/x86/virt/vmx/tdx/tdx.c=77=static int try_init_module_global(void)\n--\narch/x86/virt/vmx/tdx/tdx.c-84-\t/* Return the \"cached\" return code. */\narch/x86/virt/vmx/tdx/tdx.c:85:\tif (tdx_module_state.sysinit_done) {\narch/x86/virt/vmx/tdx/tdx.c:86:\t\tret = tdx_module_state.sysinit_ret;\narch/x86/virt/vmx/tdx/tdx.c-87-\t\tgoto out;\n--\narch/x86/virt/vmx/tdx/tdx.c-102-\t/* Save the return code for later callers. */\narch/x86/virt/vmx/tdx/tdx.c:103:\ttdx_module_state.sysinit_done = true;\narch/x86/virt/vmx/tdx/tdx.c:104:\ttdx_module_state.sysinit_ret = ret;\narch/x86/virt/vmx/tdx/tdx.c-105-out:\n--\narch/x86/virt/vmx/tdx/tdx.c=1226=static __init int tdx_enable(void)\n--\narch/x86/virt/vmx/tdx/tdx.c-1264-\narch/x86/virt/vmx/tdx/tdx.c:1265:\ttdx_module_state.initialized = true;\narch/x86/virt/vmx/tdx/tdx.c-1266-\tpr_info(\"TDX-Module initialized\\n\");\n--\narch/x86/virt/vmx/tdx/tdx.c=1271=int tdx_module_shutdown(void)\n--\narch/x86/virt/vmx/tdx/tdx.c-1301-\t */\narch/x86/virt/vmx/tdx/tdx.c:1302:\tmemset(\u0026tdx_module_state, 0, sizeof(tdx_module_state));\narch/x86/virt/vmx/tdx/tdx.c-1303-\tfor_each_possible_cpu(cpu)\n--\narch/x86/virt/vmx/tdx/tdx.c=1309=int tdx_module_run_update(void)\n--\narch/x86/virt/vmx/tdx/tdx.c-1324-\narch/x86/virt/vmx/tdx/tdx.c:1325:\ttdx_module_state.initialized = true;\narch/x86/virt/vmx/tdx/tdx.c-1326-\treturn 0;\n--\narch/x86/virt/vmx/tdx/tdx.c=1588=const struct tdx_sys_info *tdx_get_sysinfo(void)\narch/x86/virt/vmx/tdx/tdx.c-1589-{\narch/x86/virt/vmx/tdx/tdx.c:1590:\tif (!tdx_module_state.initialized)\narch/x86/virt/vmx/tdx/tdx.c-1591-\t\treturn NULL;\n"
}

gemini-3.8-flash

null

null

							input: 35483
							output: 18
							thoughts: 35
						

Okay, let's break this down.

**Initial Assessment of TDX Initialization**

Alright, so `tdx_enable` is clearly the key function here. It seems to be the entry point for, or at least a significant step in, the Trusted Domain Extension (TDX) module initialization. My immediate thought is, "Okay, good. `tdx_enable` sets the flag `tdx_module_state.initialized` to `true`." That confirms the module's been started, but that's just the tip of the iceberg, isn't it? The real question is: where *else* is `tdx_enable` being called? Understanding the call sites is where the real work begins to understand the context. That's where I need to start digging.

{
  "Expression": "tdx_enable"
}

{
  "Output": "arch/x86/virt/vmx/tdx/tdx.c=1145=static __init int init_tdx_module(void)\n--\narch/x86/virt/vmx/tdx/tdx.c-1225-\narch/x86/virt/vmx/tdx/tdx.c:1226:static __init int tdx_enable(void)\narch/x86/virt/vmx/tdx/tdx.c-1227-{\n--\narch/x86/virt/vmx/tdx/tdx.c-1268-}\narch/x86/virt/vmx/tdx/tdx.c:1269:subsys_initcall(tdx_enable);\narch/x86/virt/vmx/tdx/tdx.c-1270-\n"
}

gemini-3.8-flash

null

null

							input: 35929
							output: 47
							thoughts: 31
						

Okay, here's my take on those thoughts, tailored for an expert audience:

**Diving into the TDX Enablement Code**

Alright, let's get down to brass tacks. I need to understand how Trust Domain Extensions (TDX) are being brought to life on x86, so I'm heading straight for the heart of the matter: `arch/x86/virt/vmx/tdx/tdx.c`. Specifically, I want to understand the `tdx_enable` function. I anticipate it'll be a key component in initializing the TDX environment. This is where the real magic happens, the point where the hardware virtualization is twisted into something even more secure and isolated. I'm expecting to find the low-level interactions with the TDX module, checks for processor features, and the necessary configurations to get a TDX guest up and running. I'll be looking for how it handles the interaction between the VMM and the TDX module to make sure the guest is launched correctly. I'm expecting the function is a crucial part of the boot process for a TDX guest, and I anticipate seeing how it verifies the TDX capabilities of the hardware. The code's going to tell me exactly how the kernel is enabling TDX, and I'm eager to dig in.

{
  "File": "arch/x86/virt/vmx/tdx/tdx.c",
  "FirstLine": 1225,
  "LineCount": 45
}

{
  "Contents": "1225:\t\n1226:\tstatic __init int tdx_enable(void)\n1227:\t{\n1228:\t\tenum cpuhp_state state;\n1229:\t\tint ret;\n1230:\t\n1231:\t\tif (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)) {\n1232:\t\t\tpr_err(\"TDX not supported by the host platform\\n\");\n1233:\t\t\treturn -ENODEV;\n1234:\t\t}\n1235:\t\n1236:\t\tif (!cpu_feature_enabled(X86_FEATURE_XSAVE)) {\n1237:\t\t\tpr_err(\"XSAVE is required for TDX\\n\");\n1238:\t\t\treturn -EINVAL;\n1239:\t\t}\n1240:\t\n1241:\t\tif (!cpu_feature_enabled(X86_FEATURE_MOVDIR64B)) {\n1242:\t\t\tpr_err(\"MOVDIR64B is required for TDX\\n\");\n1243:\t\t\treturn -EINVAL;\n1244:\t\t}\n1245:\t\n1246:\t\tif (!cpu_feature_enabled(X86_FEATURE_SELFSNOOP)) {\n1247:\t\t\tpr_err(\"Self-snoop is required for TDX\\n\");\n1248:\t\t\treturn -ENODEV;\n1249:\t\t}\n1250:\t\n1251:\t\tstate = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, \"virt/tdx:online\",\n1252:\t\t\t\t\t  tdx_online_cpu, tdx_offline_cpu);\n1253:\t\tif (state \u003c 0)\n1254:\t\t\treturn state;\n1255:\t\n1256:\t\tret = init_tdx_module();\n1257:\t\tif (ret) {\n1258:\t\t\tpr_err(\"TDX-Module initialization failed (%d)\\n\", ret);\n1259:\t\t\tcpuhp_remove_state(state);\n1260:\t\t\treturn ret;\n1261:\t\t}\n1262:\t\n1263:\t\tregister_syscore(\u0026tdx_syscore);\n1264:\t\n1265:\t\ttdx_module_state.initialized = true;\n1266:\t\tpr_info(\"TDX-Module initialized\\n\");\n1267:\t\treturn 0;\n1268:\t}\n1269:\tsubsys_initcall(tdx_enable);\n"
}

gemini-3.8-flash

null

null

							input: 36955
							output: 47
							thoughts: 38
						

Okay, here's my understanding, delivered as a first-person summary, keeping in mind the expert user:

**Deep Dive into TDX Module Initialization**

Alright, so `tdx_enable` is the entry point, and my initial hunch is confirmed: it's kicking off the core TDX initialization. The immediate jump to `init_tdx_module()` is expected, and that tells me we're likely dealing with the heavy lifting of registering the module and setting up the communication with the SEAM. No surprises there. The crucial piece is confirmed - SEAMCALLs are *definitely* going to be involved in the `init_tdx_module()` path. I need to now scrutinize `init_tdx_module()` in detail. The SEAMCALL setup and the specifics of what data is being passed through them will be where the interesting stuff lies, from a security and performance perspective. That's where I can expect to find the meat of the module's core functionality, security checks, and resource allocations. Let's see how that looks.

{
  "File": "arch/x86/virt/vmx/tdx/tdx.c",
  "FirstLine": 1145,
  "LineCount": 50
}

{
  "Contents": "1145:\tstatic __init int init_tdx_module(void)\n1146:\t{\n1147:\t\tint ret;\n1148:\t\n1149:\t\tret = get_tdx_sys_info(\u0026tdx_sysinfo);\n1150:\t\tif (ret)\n1151:\t\t\treturn ret;\n1152:\t\n1153:\t\t/* Check whether the kernel can support this module */\n1154:\t\tret = check_features(\u0026tdx_sysinfo);\n1155:\t\tif (ret)\n1156:\t\t\treturn ret;\n1157:\t\n1158:\t\t/*\n1159:\t\t * To keep things simple, assume that all TDX-protected memory\n1160:\t\t * will come from the page allocator.  Make sure all pages in the\n1161:\t\t * page allocator are TDX-usable memory.\n1162:\t\t *\n1163:\t\t * Build the list of \"TDX-usable\" memory regions which cover all\n1164:\t\t * pages in the page allocator to guarantee that.  Do it while\n1165:\t\t * holding mem_hotplug_lock read-lock as the memory hotplug code\n1166:\t\t * path reads the @tdx_memlist to reject any new memory.\n1167:\t\t */\n1168:\t\tget_online_mems();\n1169:\t\n1170:\t\tret = build_tdx_memlist(\u0026tdx_memlist);\n1171:\t\tif (ret)\n1172:\t\t\tgoto out_put_tdxmem;\n1173:\t\n1174:\t\t/* Allocate enough space for constructing TDMRs */\n1175:\t\tret = alloc_tdmr_list(\u0026tdx_tdmr_list, \u0026tdx_sysinfo.tdmr);\n1176:\t\tif (ret)\n1177:\t\t\tgoto err_free_tdxmem;\n1178:\t\n1179:\t\t/* Cover all TDX-usable memory regions in TDMRs */\n1180:\t\tret = construct_tdmrs(\u0026tdx_memlist, \u0026tdx_tdmr_list, \u0026tdx_sysinfo.tdmr);\n1181:\t\tif (ret)\n1182:\t\t\tgoto err_free_tdmrs;\n1183:\t\n1184:\t\t/* Pass the TDMRs and the global KeyID to the TDX module */\n1185:\t\tret = config_tdx_module(\u0026tdx_tdmr_list, tdx_global_keyid);\n1186:\t\tif (ret)\n1187:\t\t\tgoto err_free_pamts;\n1188:\t\n1189:\t\t/* Config the key of global KeyID on all packages */\n1190:\t\tret = config_global_keyid();\n1191:\t\tif (ret)\n1192:\t\t\tgoto err_reset_pamts;\n1193:\t\n1194:\t\t/* Initialize TDMRs to complete the TDX module initialization */\n"
}

gemini-3.8-flash

null

null

							input: 38050
							output: 19
							thoughts: 666
						

**My Analysis of TDX Host Code Reachability**

Okay, so I'm digging into this `init_tdx_module()` function, and it's calling `get_tdx_sys_info` and then `seamcall()`. Wait a minute, `SEAMCALL`! That's a hardware instruction (`0f 01 cf`) that jumps into the TDX Module, loaded by firmware in SEAM Range. Interesting. But can I actually *run* these `SEAMCALL` instructions, say, in QEMU or on GCE?

Let's think. I need to figure out if QEMU or Google Compute Engine support Intel TDX either as a host or in a nested configuration. The context here is fuzzing. The key question is, can I even *reach* the code I'm looking at in a virtualized environment? I know that fuzzing is only effective on executable code in standard environments. If the code is structurally unreachable, fuzzing is pointless, assertions or complexity notwithstanding.

Can QEMU emulate a TDX host? No, QEMU doesn't emulate the TDX hardware directly - not the SEAM mode, the `SEAMCALL` instruction, or anything else. A TDX host needs a physical 4th/5th generation Intel Xeon Scalable processor (Sapphire Rapids / Emerald Rapids / Granite Rapids) with TDX enabled in BIOS, plus the MKTME keyids, the Intel TDX SEAM loader, and the TDX Module loaded into the SEAMRR (Secure Arbitration Mode Range Register).

Alright, what about QEMU as a TDX guest? Even for a TDX guest, QEMU needs KVM with TDX host support on the host, and that still requires the physical hardware. But here, the code I'm looking at, the modified code, is in the TDX HOST KVM implementation (`arch/x86/kvm/vmx/tdx.c`)!

So, the critical question: is there *any* way to reach this KVM TDX host code without physical TDX hardware? Let's trace it. I'm looking at `tdx_hardware_setup`. There's a check:

```c
	if (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)) {
		pr_err("TDX not supported by the host platform\n");
		goto success_disable_tdx;
	}
```

If `X86_FEATURE_TDX_HOST_PLATFORM` isn't enabled, `enable_tdx` is set to 0. And if `enable_tdx == 0`:

In `vt_init`:
`if (enable_tdx) kvm_caps.supported_vm_types |= BIT(KVM_X86_TDX_VM);`

So, `KVM_X86_TDX_VM` is NOT in `kvm_caps.supported_vm_types`.

Then if userspace tries `ioctl(kvm, KVM_CREATE_VM, KVM_X86_TDX_VM)`... I need to check how that handles `kvm_caps.supported_vm_types` to complete my analysis!

{
  "Expression": "supported_vm_types"
}

{
  "Output": "arch/x86/include/asm/kvm_host.h=255=struct kvm_caps {\n--\narch/x86/include/asm/kvm_host.h-270-\t/* bit mask of VM types */\narch/x86/include/asm/kvm_host.h:271:\tu32 supported_vm_types;\narch/x86/include/asm/kvm_host.h-272-\n--\narch/x86/kvm/svm/sev.c=3087=void __init sev_hardware_setup(void)\n--\narch/x86/kvm/svm/sev.c-3233-\t\tvm_types |= BIT(KVM_X86_SNP_VM);\narch/x86/kvm/svm/sev.c:3234:\tvm_types \u0026= sev_firmware_supported_vm_types();\narch/x86/kvm/svm/sev.c-3235-\narch/x86/kvm/svm/sev.c:3236:\tkvm_caps.supported_vm_types |= vm_types;\narch/x86/kvm/svm/sev.c-3237-\n--\narch/x86/kvm/vmx/main.c=1158=static int __init vt_init(void)\n--\narch/x86/kvm/vmx/main.c-1178-\t\t\t\t__alignof__(struct vcpu_tdx));\narch/x86/kvm/vmx/main.c:1179:\t\tkvm_caps.supported_vm_types |= BIT(KVM_X86_TDX_VM);\narch/x86/kvm/vmx/main.c-1180-\t}\n--\narch/x86/kvm/x86.c=2147=static bool kvm_is_vm_type_supported(unsigned long type)\narch/x86/kvm/x86.c-2148-{\narch/x86/kvm/x86.c:2149:\treturn type \u003c 32 \u0026\u0026 (kvm_caps.supported_vm_types \u0026 BIT(type));\narch/x86/kvm/x86.c-2150-}\n--\narch/x86/kvm/x86.c=2157=int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)\n--\narch/x86/kvm/x86.c-2358-\tcase KVM_CAP_VM_TYPES:\narch/x86/kvm/x86.c:2359:\t\tr = kvm_caps.supported_vm_types;\narch/x86/kvm/x86.c-2360-\t\tbreak;\n--\narch/x86/kvm/x86.c=6953=int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)\n--\narch/x86/kvm/x86.c-7016-\narch/x86/kvm/x86.c:7017:\tkvm_caps.supported_vm_types = BIT(KVM_X86_DEFAULT_VM);\narch/x86/kvm/x86.c-7018-\tkvm_caps.supported_mce_cap = MCG_CTL_P | MCG_SER_P;\n--\narch/x86/kvm/x86.c-7078-\tif (IS_ENABLED(CONFIG_KVM_SW_PROTECTED_VM) \u0026\u0026 tdp_mmu_enabled)\narch/x86/kvm/x86.c:7079:\t\tkvm_caps.supported_vm_types |= BIT(KVM_X86_SW_PROTECTED_VM);\narch/x86/kvm/x86.c-7080-\n--\ndrivers/crypto/ccp/sev-dev.c=3134=static bool sev_firmware_allows_es(struct sev_device *sev)\n--\ndrivers/crypto/ccp/sev-dev.c-3144-\ndrivers/crypto/ccp/sev-dev.c:3145:int sev_firmware_supported_vm_types(void)\ndrivers/crypto/ccp/sev-dev.c-3146-{\ndrivers/crypto/ccp/sev-dev.c:3147:\tint supported_vm_types = 0;\ndrivers/crypto/ccp/sev-dev.c-3148-\tstruct sev_device *sev;\n--\ndrivers/crypto/ccp/sev-dev.c-3150-\tif (!psp_master || !psp_master-\u003esev_data)\ndrivers/crypto/ccp/sev-dev.c:3151:\t\treturn supported_vm_types;\ndrivers/crypto/ccp/sev-dev.c-3152-\tsev = psp_master-\u003esev_data;\ndrivers/crypto/ccp/sev-dev.c-3153-\ndrivers/crypto/ccp/sev-dev.c:3154:\tsupported_vm_types |= BIT(KVM_X86_SEV_VM);\ndrivers/crypto/ccp/sev-dev.c:3155:\tsupported_vm_types |= BIT(KVM_X86_SEV_ES_VM);\ndrivers/crypto/ccp/sev-dev.c-3156-\ndrivers/crypto/ccp/sev-dev.c-3157-\tif (!sev-\u003esnp_initialized)\ndrivers/crypto/ccp/sev-dev.c:3158:\t\treturn supported_vm_types;\ndrivers/crypto/ccp/sev-dev.c-3159-\ndrivers/crypto/ccp/sev-dev.c:3160:\tsupported_vm_types |= BIT(KVM_X86_SNP_VM);\ndrivers/crypto/ccp/sev-dev.c-3161-\ndrivers/crypto/ccp/sev-dev.c-3162-\tif (!sev_firmware_allows_es(sev))\ndrivers/crypto/ccp/sev-dev.c:3163:\t\tsupported_vm_types \u0026= ~BIT(KVM_X86_SEV_ES_VM);\ndrivers/crypto/ccp/sev-dev.c-3164-\ndrivers/crypto/ccp/sev-dev.c:3165:\treturn supported_vm_types;\ndrivers/crypto/ccp/sev-dev.c-3166-\ndrivers/crypto/ccp/sev-dev.c-3167-}\ndrivers/crypto/ccp/sev-dev.c:3168:EXPORT_SYMBOL_FOR_MODULES(sev_firmware_supported_vm_types, \"kvm-amd\");\n--\ninclude/linux/psp-sev.h=1137=u64 sev_get_snp_policy_bits(void);\ninclude/linux/psp-sev.h:1138:int sev_firmware_supported_vm_types(void);\ninclude/linux/psp-sev.h-1139-\n"
}

gemini-3.8-flash

null

null

							input: 41251
							output: 27
							thoughts: 2416
						

**TDX Reachability Analysis in Standard Virtualized Environments**

Okay, here's my assessment of this TDX code and its reachability: Based on my understanding of KVM and TDX, it's immediately apparent that the code paths related to TDX guest handling, specifically `tdx_handle_ept_violation` and everything it touches, are fundamentally unreachable in standard virtualization environments like QEMU and GCE.

First, the core of this assessment hinges on `kvm_is_vm_type_supported()`. For a VM to even *be* a TDX VM (`KVM_X86_TDX_VM`), the `kvm_caps.supported_vm_types` must include `BIT(KVM_X86_TDX_VM)`. This bit is only set if `enable_tdx` is true, and that, crucially, is *only* set if a series of checks pass during TDX hardware setup (`tdx_hardware_setup()`). These checks require a *real* TDX-capable CPU (specifically, a Sapphire Rapids or newer Intel Xeon), and crucially the presence of the TDX Host Platform feature flag. Even if the feature flag somehow got flipped, `__tdx_hardware_setup()` further demands that the `tdx_get_sysinfo()` function works. This in turn needs an initialized TDX module, that can only happen when the physical hardware is capable of executing SEAMCALL instructions against the TDX module firmware.

The essential point is that the *entire* TDX guest execution is mediated by the Intel TDX SEAM module. It depends on SEAMCALLs: `TDH_MNG_INIT`, `TDH_VP_INIT`, `TDH_MEM_SEPT_ADD`, `TDH_MEM_PAGE_ADD`, and, most significantly, `TDH_VP_ENTER`. Without the underlying TDX hardware, this SEAM module is absent, and these SEAMCALL instructions *cannot* function. Any attempt to use them results in CPU exception.

Now, considering QEMU and GCE: neither provides TDX host *emulation* or *support*. GCE's hypervisor doesn't expose TDX host capabilities, and QEMU does *not* emulate the Intel TDX SEAM module or any of its associated instructions. There is *no* software implementation or simulation of this. This is very, very important.

Let's look at the triage criteria. The guidelines state clearly that we should mark code as non-fuzzable if it's "structurally unreachable hardware" – such as hardware requiring physical components not emulated in standard QEMU. This is precisely the case here. TDX requires physical TDX hardware components (MSRs, SEAM module firmware, and the ability to execute SEAMCALLs), and these are not, and *cannot* be, emulated in standard virtualized environments.

Focusing on the specific code in question, `tdx_handle_ept_violation`: This function is called during VM exits related to EPT violations. For *this* function to even *run*, the VM has to be a TDX VM, which, as established above, implies TDX hardware. It is only called in `tdx_handle_exit`, which, in turn, is only called if the vCPU is an TDX one. Thus if the code *is* called, it will be by virtue of having a TDX capable VM running on hardware capable of SEAMCALLS.

I've even traced the path of `X86_FEATURE_TDX_HOST_PLATFORM` and can confirm that its feature flag is only set if `record_keyid_partitioning` successfully reads from a TDX-related MSR. On non-TDX hardware, the call returns an error, preventing the feature flag from being set, thus blocking any other TDX-related calls from succeeding. Even if that feature flag were to be spoofed, there's the call to `tdx_get_sysinfo()` which would require an initialized TDX module, but to initialize that module it must be able to use the SEAMCALLS. In a standard QEMU / GCE setup, SEAMCALLs will generate an exception.

In summary, given the architecture, the code is fundamentally unreachable in a standard QEMU or GCE environment. We need to focus on code that can execute on standard virtualized hardware, with software emulated devices. TDX is outside the scope of such environments. I would therefore conclude that `tdx_handle_ept_violation` and anything that calls it is structurally unreachable in the context we're considering, and it's not worth fuzzing.

{
  "Expression": "KVM_X86_SW_PROTECTED_VM"
}

{
  "Output": "Documentation/virt/kvm/api.rst=9602=means the VM type with value @n is supported.  Possible values of @n are::\n--\nDocumentation/virt/kvm/api.rst-9604-  #define KVM_X86_DEFAULT_VM\t0\nDocumentation/virt/kvm/api.rst:9605:  #define KVM_X86_SW_PROTECTED_VM\t1\nDocumentation/virt/kvm/api.rst-9606-  #define KVM_X86_SEV_VM\t2\n--\nDocumentation/virt/kvm/api.rst-9610-\nDocumentation/virt/kvm/api.rst:9611:Note, KVM_X86_SW_PROTECTED_VM is currently only for development and testing.\nDocumentation/virt/kvm/api.rst:9612:Do not use KVM_X86_SW_PROTECTED_VM for \"real\" VMs, and especially not in\nDocumentation/virt/kvm/api.rst-9613-production.  The behavior and effective ABI for software-protected VMs is\n--\narch/x86/include/uapi/asm/kvm.h=927=struct kvm_hyperv_eventfd {\n--\narch/x86/include/uapi/asm/kvm.h-970-#define KVM_X86_DEFAULT_VM\t0\narch/x86/include/uapi/asm/kvm.h:971:#define KVM_X86_SW_PROTECTED_VM\t1\narch/x86/include/uapi/asm/kvm.h-972-#define KVM_X86_SEV_VM\t\t2\n--\narch/x86/kvm/mmu/mmu.c=6635=int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code,\n--\narch/x86/kvm/mmu/mmu.c-6653-\t    !(error_code \u0026 PFERR_RSVD_MASK) \u0026\u0026\narch/x86/kvm/mmu/mmu.c:6654:\t    vcpu-\u003ekvm-\u003earch.vm_type == KVM_X86_SW_PROTECTED_VM \u0026\u0026\narch/x86/kvm/mmu/mmu.c-6655-\t    kvm_is_private_gfn(vcpu-\u003ekvm, gpa_to_gfn(cr2_or_gpa)))\n--\narch/x86/kvm/svm/sev.c=2956=void sev_vm_init(struct kvm *kvm)\n--\narch/x86/kvm/svm/sev.c-2959-\tcase KVM_X86_DEFAULT_VM:\narch/x86/kvm/svm/sev.c:2960:\tcase KVM_X86_SW_PROTECTED_VM:\narch/x86/kvm/svm/sev.c-2961-\t\tbreak;\n--\narch/x86/kvm/x86.c=6953=int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)\n--\narch/x86/kvm/x86.c-7078-\tif (IS_ENABLED(CONFIG_KVM_SW_PROTECTED_VM) \u0026\u0026 tdp_mmu_enabled)\narch/x86/kvm/x86.c:7079:\t\tkvm_caps.supported_vm_types |= BIT(KVM_X86_SW_PROTECTED_VM);\narch/x86/kvm/x86.c-7080-\n--\narch/x86/kvm/x86.c=9800=int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)\n--\narch/x86/kvm/x86.c-9809-\tkvm-\u003earch.has_private_mem =\narch/x86/kvm/x86.c:9810:\t\t(type == KVM_X86_SW_PROTECTED_VM);\narch/x86/kvm/x86.c-9811-\t/* Decided by the vendor code for other VM types.  */\narch/x86/kvm/x86.c-9812-\tkvm-\u003earch.pre_fault_allowed =\narch/x86/kvm/x86.c:9813:\t\ttype == KVM_X86_DEFAULT_VM || type == KVM_X86_SW_PROTECTED_VM;\narch/x86/kvm/x86.c-9814-\tkvm-\u003earch.disabled_quirks = kvm_caps.inapplicable_quirks \u0026 kvm_caps.supported_quirks;\n--\ntools/arch/x86/include/uapi/asm/kvm.h=927=struct kvm_hyperv_eventfd {\n--\ntools/arch/x86/include/uapi/asm/kvm.h-970-#define KVM_X86_DEFAULT_VM\t0\ntools/arch/x86/include/uapi/asm/kvm.h:971:#define KVM_X86_SW_PROTECTED_VM\t1\ntools/arch/x86/include/uapi/asm/kvm.h-972-#define KVM_X86_SEV_VM\t\t2\n--\ntools/testing/selftests/kvm/pre_fault_memory_test.c=220=int main(int argc, char *argv[])\n--\ntools/testing/selftests/kvm/pre_fault_memory_test.c-225-#ifdef __x86_64__\ntools/testing/selftests/kvm/pre_fault_memory_test.c:226:\ttest_pre_fault_memory(KVM_X86_SW_PROTECTED_VM, false);\ntools/testing/selftests/kvm/pre_fault_memory_test.c:227:\ttest_pre_fault_memory(KVM_X86_SW_PROTECTED_VM, true);\ntools/testing/selftests/kvm/pre_fault_memory_test.c-228-#endif\n--\ntools/testing/selftests/kvm/set_memory_region_test.c=346=static void test_invalid_memory_region_flags(void)\n--\ntools/testing/selftests/kvm/set_memory_region_test.c-357-#ifdef __x86_64__\ntools/testing/selftests/kvm/set_memory_region_test.c:358:\tif (kvm_check_cap(KVM_CAP_VM_TYPES) \u0026 BIT(KVM_X86_SW_PROTECTED_VM))\ntools/testing/selftests/kvm/set_memory_region_test.c:359:\t\tvm = vm_create_barebones_type(KVM_X86_SW_PROTECTED_VM);\ntools/testing/selftests/kvm/set_memory_region_test.c-360-\telse\n--\ntools/testing/selftests/kvm/set_memory_region_test.c=467=static void test_add_private_memory_region(void)\n--\ntools/testing/selftests/kvm/set_memory_region_test.c-473-\ntools/testing/selftests/kvm/set_memory_region_test.c:474:\tvm = vm_create_barebones_type(KVM_X86_SW_PROTECTED_VM);\ntools/testing/selftests/kvm/set_memory_region_test.c-475-\n--\ntools/testing/selftests/kvm/set_memory_region_test.c-482-\ntools/testing/selftests/kvm/set_memory_region_test.c:483:\tvm2 = vm_create_barebones_type(KVM_X86_SW_PROTECTED_VM);\ntools/testing/selftests/kvm/set_memory_region_test.c-484-\tmemfd = vm_create_guest_memfd(vm2, MEM_REGION_SIZE, 0);\n--\ntools/testing/selftests/kvm/set_memory_region_test.c=503=static void test_add_overlapping_private_memory_regions(void)\n--\ntools/testing/selftests/kvm/set_memory_region_test.c-510-\ntools/testing/selftests/kvm/set_memory_region_test.c:511:\tvm = vm_create_barebones_type(KVM_X86_SW_PROTECTED_VM);\ntools/testing/selftests/kvm/set_memory_region_test.c-512-\n--\ntools/testing/selftests/kvm/set_memory_region_test.c=623=int main(int argc, char *argv[])\n--\ntools/testing/selftests/kvm/set_memory_region_test.c-644-\tif (kvm_has_cap(KVM_CAP_GUEST_MEMFD) \u0026\u0026\ntools/testing/selftests/kvm/set_memory_region_test.c:645:\t    (kvm_check_cap(KVM_CAP_VM_TYPES) \u0026 BIT(KVM_X86_SW_PROTECTED_VM))) {\ntools/testing/selftests/kvm/set_memory_region_test.c-646-\t\ttest_add_private_memory_region();\n--\ntools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c=40=static void gmem_conversions_do_setup(test_data_t *t, int nr_pages,\n--\ntools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c-44-\t\t.mode = VM_MODE_DEFAULT,\ntools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c:45:\t\t.type = KVM_X86_SW_PROTECTED_VM,\ntools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c-46-\t};\n--\ntools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c=503=int main(int argc, char *argv[])\ntools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c-504-{\ntools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c:505:\tTEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) \u0026 BIT(KVM_X86_SW_PROTECTED_VM));\ntools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c-506-\tTEST_REQUIRE(kvm_check_cap(KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES) \u0026\n--\ntools/testing/selftests/kvm/x86/private_mem_conversions_test.c=401=static void test_mem_conversions(enum vm_mem_backing_src_type src_type, u32 nr_vcpus,\n--\ntools/testing/selftests/kvm/x86/private_mem_conversions_test.c-414-\t\t.mode = VM_MODE_DEFAULT,\ntools/testing/selftests/kvm/x86/private_mem_conversions_test.c:415:\t\t.type = KVM_X86_SW_PROTECTED_VM,\ntools/testing/selftests/kvm/x86/private_mem_conversions_test.c-416-\t};\n--\ntools/testing/selftests/kvm/x86/private_mem_conversions_test.c=482=int main(int argc, char *argv[])\n--\ntools/testing/selftests/kvm/x86/private_mem_conversions_test.c-488-\ntools/testing/selftests/kvm/x86/private_mem_conversions_test.c:489:\tTEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) \u0026 BIT(KVM_X86_SW_PROTECTED_VM));\ntools/testing/selftests/kvm/x86/private_mem_conversions_test.c-490-\n--\ntools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c=42=const struct vm_shape protected_vm_shape = {\ntools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c-43-\t.mode = VM_MODE_DEFAULT,\ntools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c:44:\t.type = KVM_X86_SW_PROTECTED_VM,\ntools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c-45-};\n--\ntools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c=137=int main(int argc, char *argv[])\ntools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c-138-{\ntools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c:139:\tTEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) \u0026 BIT(KVM_X86_SW_PROTECTED_VM));\ntools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c-140-\n--\ntools/testing/selftests/kvm/x86/sev_init2_tests.c=76=void test_vm_types(void)\n--\ntools/testing/selftests/kvm/x86/sev_init2_tests.c-87-\t\t\t   \"VM type is KVM_X86_DEFAULT_VM\");\ntools/testing/selftests/kvm/x86/sev_init2_tests.c:88:\tif (kvm_check_cap(KVM_CAP_VM_TYPES) \u0026 BIT(KVM_X86_SW_PROTECTED_VM))\ntools/testing/selftests/kvm/x86/sev_init2_tests.c:89:\t\ttest_init2_invalid(KVM_X86_SW_PROTECTED_VM, \u0026(struct kvm_sev_init){},\ntools/testing/selftests/kvm/x86/sev_init2_tests.c:90:\t\t\t\t   \"VM type is KVM_X86_SW_PROTECTED_VM\");\ntools/testing/selftests/kvm/x86/sev_init2_tests.c-91-}\n"
}

gemini-3.8-flash

null

null

							input: 48545
							output: 206
							thoughts: 1636
						

**Analysis of TDX Host Reachability for Fuzzing**

Alright, let's break this down. My initial thought is that `KVM_X86_SW_PROTECTED_VM` is definitively *not* the same as `KVM_X86_TDX_VM`. The code explicitly checks `kvm->arch.vm_type` against `KVM_X86_TDX_VM` using `is_td()`, and because the constants are different (1 vs 5), that check will always fail for software protected VMs. Consequently, the conditional logic within the `is_td` block, specifically concerning functions like `tdx_handle_exit` and `tdx_handle_ept_violation`, is never executed when the VM is configured as `KVM_X86_SW_PROTECTED_VM`.

I need to confirm that `KVM_X86_TDX_VM` can only be created if `enable_tdx` is set. This requires `cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)` and a successful `__tdx_hardware_setup()`.  `enable_tdx` is set to zero unless specific conditions are met: the presence of `X86_FEATURE_TDX_HOST_PLATFORM` (which ties into hardware support for things like MSR IA32_MKTME_KEYID_PARTITIONING) and a successfully loaded TDX SEAM module, established by calls like `tdx_get_sysinfo()` within `__tdx_hardware_setup()`.

Then, I'm thinking about the standard virtualized environments. Neither standard QEMU (TCG or KVM without a physical TDX host) nor standard cloud VMs, like those in GCE, provide support for an Intel TDX *host* platform.  This means that the code path within `tdx_handle_ept_violation` is fundamentally unreachable in these typical fuzzing setups.

Let me double-check my assumptions based on the "negative criteria" in Section 2, looking for examples of structurally unreachable code. Things like vendor-specific PCIe switches, SmartNICs, or GPU drivers (such as `mlxsw`, `pds_core`, `qed`, `ionic`, or `amdgpu`) are clearly off-limits because they rely on physical ASIC/PCIe cards that are not emulated in standard QEMU. That is supported by Section 1: REACHABILITY IS THE PRIMARY GATE.

Wait, can syzkaller be used to fuzz TDX host on physical TDX hardware?

The Syzkaller documentation emphasizes reachability.  The text clearly limits fuzzing to what can run in *standard* virtualized environments (GCE or QEMU). Intel TDX host requires *physical* bare-metal 4th/5th Gen Xeon Scalable processors with BIOS-level TDX enablement and authenticated SEAM firmware, none of which is available within standard QEMU or GCE environments.

Let's carefully examine the patch itself. It's modifying code within `tdx_handle_ept_violation()`. The original code killed the whole VM with `kvm_vm_dead()` and returned `-EIO`. The patch replaces this with `kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu)` to inject a triple fault into the vCPU and returns 1. This change is entirely within the TDX Secure EPT violation handling and thus only reachable on a TDX VM running on a TDX host.

Because the patch *only* modifies code within `arch/x86/kvm/vmx/tdx.c` that specifically handles TDX Secure EPT violations *for Intel TDX VMs*, and because this requires very specific physical hardware that's *not* available in standard QEMU or GCE environments, the modified code is structurally unreachable. Therefore, this change is not worth fuzzing.

Let's prepare the tool call:
```
set-results:
- WorthFuzzing: false
- EnableConfigs: []
- FocusSymbols: []
- Reasoning: "The patch modifies `tdx_handle_ept_violation()` in `arch/x86/kvm/vmx/tdx.c`, which handles Secure EPT (SEPT) violations for Intel TDX guest VMs. Intel TDX host support requires physical CPU support (Intel 4th/5th Gen Xeon or newer) with TDX enabled in firmware and the Intel TDX SEAM module loaded. Without this physical hardware, `X86_FEATURE_TDX_HOST_PLATFORM` is not present, `enable_tdx` remains disabled, and `KVM_X86_TDX_

{
  "EnableConfigs": [],
  "FocusSymbols": [],
  "Reasoning": "The patch modifies tdx_handle_ept_violation() in arch/x86/kvm/vmx/tdx.c, which handles Secure EPT (SEPT) violations for Intel TDX guests. Intel TDX host support requires physical hardware (Intel 4th/5th Gen Xeon or newer) with TDX enabled in firmware/BIOS and an authenticated Intel TDX SEAM module loaded into SEAMRR. Without this specialized physical hardware, X86_FEATURE_TDX_HOST_PLATFORM is disabled, enable_tdx is set to false, and TDX VMs (KVM_X86_TDX_VM) cannot be created. Because TDX host virtualization is not emulated in standard QEMU or supported in GCE virtualized environments, the modified code is structurally unreachable for fuzzing.",
  "WorthFuzzing": false
}

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch modifies tdx_handle_ept_violation() in arch/x86/kvm/vmx/tdx.c, which handles Secure EPT (SEPT) violations for Intel TDX guests. Intel TDX host support requires physical hardware (Intel 4th/5th Gen Xeon or newer) with TDX enabled in firmware/BIOS and an authenticated Intel TDX SEAM module loaded into SEAMRR. Without this specialized physical hardware, X86_FEATURE_TDX_HOST_PLATFORM is disabled, enable_tdx is set to false, and TDX VMs (KVM_X86_TDX_VM) cannot be created. Because TDX host virtualization is not emulated in standard QEMU or supported in GCE virtualized environments, the modified code is structurally unreachable for fuzzing.",
  "WorthFuzzing": false
}

{
  "WorthFuzzing": false
}

null