| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/08/10 12:52 | flow | patch-triage |
1mArgs:null Results: {
"EnableConfigs": null,
"FocusSymbols": [],
"KMSANReasoning": "",
"NeedsKMSAN": false,
"Reasoning": "The patch modifies KVM TDX (Trust Domain Extensions) code, which requires specific physical hardware support (Intel TDX) not emulated in standard QEMU/GCE environments. The changes to standard VMX code are purely refactoring to share logic with TDX, with no functional impact.",
"WorthFuzzing": false
} |
| 1/1 | 2026/08/10 12:52 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit 66b46b058899bd0f496b52d7b19133a81e81ee9b\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Mon Aug 10 12:52:35 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h\nindex 08005676702c2..2cbaa9aba901c 100644\n--- a/arch/x86/kvm/vmx/common.h\n+++ b/arch/x86/kvm/vmx/common.h\n@@ -4,6 +4,7 @@\n \n #include \u003clinux/kvm_host.h\u003e\n #include \u003casm/posted_intr.h\u003e\n+#include \u003casm/vmx.h\u003e\n \n #include \"mmu.h\"\n \n@@ -183,6 +184,24 @@ static inline void __vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu,\n \tkvm_vcpu_trigger_posted_interrupt(vcpu, POSTED_INTR_VECTOR);\n }\n \n+static inline int __vmx_handle_notify(struct kvm_vcpu *vcpu,\n+\t\t\t\t unsigned long exit_qual)\n+{\n+\tbool context_invalid = exit_qual \u0026 NOTIFY_VM_CONTEXT_INVALID;\n+\n+\t++vcpu-\u003estat.notify_window_exits;\n+\n+\tif (vcpu-\u003ekvm-\u003earch.notify_vmexit_flags \u0026 KVM_X86_NOTIFY_VMEXIT_USER ||\n+\t context_invalid) {\n+\t\tvcpu-\u003erun-\u003eexit_reason = KVM_EXIT_NOTIFY;\n+\t\tvcpu-\u003erun-\u003enotify.flags = context_invalid ?\n+\t\t\t\t\t KVM_NOTIFY_CONTEXT_INVALID : 0;\n+\t\treturn 0;\n+\t}\n+\n+\treturn 1;\n+}\n+\n noinstr void vmx_handle_nmi(struct kvm_vcpu *vcpu);\n \n #endif /* __KVM_X86_VMX_COMMON_H */\ndiff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c\nindex b272c20586a74..ac3f71643cd5e 100644\n--- a/arch/x86/kvm/vmx/tdx.c\n+++ b/arch/x86/kvm/vmx/tdx.c\n@@ -921,10 +921,10 @@ static __always_inline u32 tdcall_to_vmx_exit_reason(struct kvm_vcpu *vcpu)\n \treturn EXIT_REASON_TDCALL;\n }\n \n-static __always_inline u32 tdx_to_vmx_exit_reason(struct kvm_vcpu *vcpu)\n+static __always_inline union vmx_exit_reason tdx_to_vmx_exit_reason(struct kvm_vcpu *vcpu)\n {\n \tstruct vcpu_tdx *tdx = to_tdx(vcpu);\n-\tu32 exit_reason;\n+\tunion vmx_exit_reason exit_reason;\n \n \tswitch (tdx-\u003evp_enter_ret \u0026 TDX_SEAMCALL_STATUS_MASK) {\n \tcase TDX_SUCCESS:\n@@ -934,23 +934,33 @@ static __always_inline u32 tdx_to_vmx_exit_reason(struct kvm_vcpu *vcpu)\n \tcase TDX_NON_RECOVERABLE_TD_WRONG_APIC_MODE:\n \t\tbreak;\n \tdefault:\n-\t\treturn -1u;\n+\t\t/*\n+\t\t * Synthesize an invalid bogus Exit Reason, as the TDX-Module\n+\t\t * never attempted to run the vCPU, i.e. the Exit Reason is\n+\t\t * undefined, but this is NOT a failed VM-Enter.\n+\t\t */\n+\t\treturn (union vmx_exit_reason) {\n+\t\t\t.basic = -1,\n+\t\t};\n \t}\n \n-\texit_reason = tdx-\u003evp_enter_ret;\n+\texit_reason.full = (u32)tdx-\u003evp_enter_ret;\n \n-\tswitch (exit_reason) {\n+\tswitch (exit_reason.basic) {\n \tcase EXIT_REASON_TDCALL:\n \t\tif (tdvmcall_exit_type(vcpu))\n-\t\t\treturn EXIT_REASON_VMCALL;\n-\n-\t\treturn tdcall_to_vmx_exit_reason(vcpu);\n+\t\t\texit_reason.basic = EXIT_REASON_VMCALL;\n+\t\telse\n+\t\t\texit_reason.basic = tdcall_to_vmx_exit_reason(vcpu);\n+\t\tbreak;\n \tcase EXIT_REASON_EPT_MISCONFIG:\n \t\t/*\n \t\t * Defer KVM_BUG_ON() until tdx_handle_exit() because this is in\n \t\t * non-instrumentable code with interrupts disabled.\n \t\t */\n-\t\treturn -1u;\n+\t\treturn (union vmx_exit_reason) {\n+\t\t\t.basic = -1,\n+\t\t};\n \tdefault:\n \t\tbreak;\n \t}\n@@ -967,7 +977,7 @@ static noinstr void tdx_vcpu_enter_exit(struct kvm_vcpu *vcpu)\n \n \ttdx-\u003evp_enter_ret = tdh_vp_enter(\u0026tdx-\u003evp, \u0026tdx-\u003evp_enter_args);\n \n-\tvt-\u003eexit_reason.full = tdx_to_vmx_exit_reason(vcpu);\n+\tvt-\u003eexit_reason = tdx_to_vmx_exit_reason(vcpu);\n \n \tvt-\u003eexit_qualification = tdx-\u003evp_enter_args.rcx;\n \ttdx-\u003eext_exit_qualification = tdx-\u003evp_enter_args.rdx;\n@@ -981,8 +991,7 @@ static noinstr void tdx_vcpu_enter_exit(struct kvm_vcpu *vcpu)\n \n static bool tdx_failed_vmentry(struct kvm_vcpu *vcpu)\n {\n-\treturn vmx_get_exit_reason(vcpu).failed_vmentry \u0026\u0026\n-\t vmx_get_exit_reason(vcpu).full != -1u;\n+\treturn vmx_get_exit_reason(vcpu).failed_vmentry;\n }\n \n static fastpath_t tdx_exit_handlers_fastpath(struct kvm_vcpu *vcpu)\n@@ -1071,8 +1080,10 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)\n \t * allowing vCPU entry to avoid contention with tdh_vp_enter() and\n \t * TDCALLs.\n \t */\n-\tif (unlikely(READ_ONCE(to_kvm_tdx(vcpu-\u003ekvm)-\u003ewait_for_sept_zap)))\n+\tif (unlikely(READ_ONCE(to_kvm_tdx(vcpu-\u003ekvm)-\u003ewait_for_sept_zap))) {\n+\t\tvt-\u003eexit_reason.bus_lock_detected = 0;\n \t\treturn EXIT_FASTPATH_EXIT_HANDLED;\n+\t}\n \n \ttrace_kvm_entry(vcpu, run_flags \u0026 KVM_RUN_FORCE_IMMEDIATE_EXIT);\n \n@@ -2028,7 +2039,7 @@ int tdx_complete_emulated_msr(struct kvm_vcpu *vcpu, int err)\n }\n \n \n-int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)\n+static int __tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)\n {\n \tstruct vcpu_tdx *tdx = to_tdx(vcpu);\n \tu64 vp_enter_ret = tdx-\u003evp_enter_ret;\n@@ -2126,6 +2137,11 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)\n \t\t * - If it's not an MSMI, no need to do anything here.\n \t\t */\n \t\treturn 1;\n+\tcase EXIT_REASON_NOTIFY:\n+\t\t/* NMI blocking state is handled by TDX module */\n+\t\treturn __vmx_handle_notify(vcpu, vmx_get_exit_qual(vcpu));\n+\tcase EXIT_REASON_BUS_LOCK:\n+\t\treturn handle_bus_lock_vmexit(vcpu);\n \tdefault:\n \t\tbreak;\n \t}\n@@ -2135,13 +2151,29 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)\n \treturn 0;\n }\n \n+int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)\n+{\n+\tint ret = __tdx_handle_exit(vcpu, fastpath);\n+\n+\t/* Exit to user space when bus lock was detected */\n+\tif (vmx_get_exit_reason(vcpu).bus_lock_detected) {\n+\t\tif (ret \u003e 0) {\n+\t\t\tvcpu-\u003erun-\u003eexit_reason = KVM_EXIT_X86_BUS_LOCK;\n+\t\t\tret = 0;\n+\t\t}\n+\n+\t\tvcpu-\u003erun-\u003eflags |= KVM_RUN_X86_BUS_LOCK;\n+\t}\n+\treturn ret;\n+}\n+\n void tdx_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,\n \t\tu64 *info1, u64 *info2, u32 *intr_info, u32 *error_code)\n {\n \tstruct vcpu_tdx *tdx = to_tdx(vcpu);\n \n \t*reason = tdx-\u003evt.exit_reason.full;\n-\tif (*reason != -1u) {\n+\tif (tdx-\u003evt.exit_reason.basic != -1) {\n \t\t*info1 = vmx_get_exit_qual(vcpu);\n \t\t*info2 = tdx-\u003eext_exit_qualification;\n \t\t*intr_info = vmx_get_intr_info(vcpu);\n@@ -3154,6 +3186,17 @@ static int tdx_vcpu_init(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *cmd)\n \ttd_vmcs_write64(tdx, POSTED_INTR_DESC_ADDR, __pa(\u0026tdx-\u003evt.pi_desc));\n \ttd_vmcs_setbit32(tdx, PIN_BASED_VM_EXEC_CONTROL, PIN_BASED_POSTED_INTR);\n \n+\tif (kvm_notify_vmexit_enabled(vcpu-\u003ekvm)) {\n+\t\ttd_vmcs_setbit32(tdx, SECONDARY_VM_EXEC_CONTROL,\n+\t\t\t\t SECONDARY_EXEC_NOTIFY_VM_EXITING);\n+\t\ttd_vmcs_write32(tdx, NOTIFY_WINDOW,\n+\t\t\t\tvcpu-\u003ekvm-\u003earch.notify_window);\n+\t}\n+\n+\tif (vcpu-\u003ekvm-\u003earch.bus_lock_detection_enabled)\n+\t\ttd_vmcs_setbit32(tdx, SECONDARY_VM_EXEC_CONTROL,\n+\t\t\t\t SECONDARY_EXEC_BUS_LOCK_DETECTION);\n+\n \ttdx-\u003estate = VCPU_TD_STATE_INITIALIZED;\n \n \treturn 0;\ndiff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c\nindex e3bfe6aca1a0e..c429db9b92057 100644\n--- a/arch/x86/kvm/vmx/vmx.c\n+++ b/arch/x86/kvm/vmx/vmx.c\n@@ -6265,7 +6265,7 @@ static int handle_encls(struct kvm_vcpu *vcpu)\n }\n #endif /* CONFIG_X86_SGX_KVM */\n \n-static int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu)\n+int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu)\n {\n \t/*\n \t * Hardware may or may not set the BUS_LOCK_DETECTED flag on BUS_LOCK\n@@ -6279,9 +6279,6 @@ static int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu)\n static int handle_notify(struct kvm_vcpu *vcpu)\n {\n \tunsigned long exit_qual = vmx_get_exit_qual(vcpu);\n-\tbool context_invalid = exit_qual \u0026 NOTIFY_VM_CONTEXT_INVALID;\n-\n-\t++vcpu-\u003estat.notify_window_exits;\n \n \t/*\n \t * Notify VM exit happened while executing iret from NMI,\n@@ -6291,15 +6288,7 @@ static int handle_notify(struct kvm_vcpu *vcpu)\n \t\tvmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,\n \t\t\t GUEST_INTR_STATE_NMI);\n \n-\tif (vcpu-\u003ekvm-\u003earch.notify_vmexit_flags \u0026 KVM_X86_NOTIFY_VMEXIT_USER ||\n-\t context_invalid) {\n-\t\tvcpu-\u003erun-\u003eexit_reason = KVM_EXIT_NOTIFY;\n-\t\tvcpu-\u003erun-\u003enotify.flags = context_invalid ?\n-\t\t\t\t\t KVM_NOTIFY_CONTEXT_INVALID : 0;\n-\t\treturn 0;\n-\t}\n-\n-\treturn 1;\n+\treturn __vmx_handle_notify(vcpu, exit_qual);\n }\n \n static int vmx_get_msr_imm_reg(struct kvm_vcpu *vcpu)\ndiff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h\nindex dc8517f15bc46..8faf04c09721c 100644\n--- a/arch/x86/kvm/vmx/vmx.h\n+++ b/arch/x86/kvm/vmx/vmx.h\n@@ -379,6 +379,7 @@ bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned int flags);\n void vmx_ept_load_pdptrs(struct kvm_vcpu *vcpu);\n \n void vmx_set_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type, bool set);\n+int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu);\n \n static inline void vmx_disable_intercept_for_msr(struct kvm_vcpu *vcpu,\n \t\t\t\t\t\t u32 msr, int type)\n"
} |
| 2/1 | 2026/08/10 12:52 | agent | patch-evaluator |
1mModel:best-expensive Args: null Results: {
"EnableConfigs": null,
"FocusSymbols": [],
"Reasoning": "The patch modifies KVM TDX (Trust Domain Extensions) code, which requires specific physical hardware support (Intel TDX) not emulated in standard QEMU/GCE environments. The changes to standard VMX code are purely refactoring to share logic with TDX, with no functional impact.",
"WorthFuzzing": false
}Instruction: You are an expert Linux kernel maintainer. Your job is to review a provided patch series and determine if it makes functional changes to the kernel that should be fuzzed. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively use your code access tools to examine the actual source code and confirm any assumptions. Return WorthFuzzing=false if the patch only contains: - Modifications to Documentation/, Kconfig files, or code comments. - Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints. - Changes to numeric constants or macros that do not functionally alter execution flow. - Code paths that are impossible to reach in virtualized environments like GCE or QEMU, even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim). - Code in vendor-specific PCIe switch, SmartNIC, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) that require physical PCIe hardware cards not emulated in standard QEMU. - Driver .remove, .shutdown, or pci_unregister_driver teardown callbacks (e.g., igb_remove) that are executed only during PCI hot-unplug or sysfs driver unbind operations. If it modifies reachable core kernel logic, drivers, or architectures, use your code search tools to verify the code can be executed, then return WorthFuzzing=true. When returning WorthFuzzing=true, you MUST ALSO: 1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols. Avoid listing generic hot-path functions to prevent skewed test distributions. Prefer non-static, non-inlined API entrypoint functions over internal static helper functions (which are inlined by the compiler and do not have distinct symbol addresses). 2. Identify any specific CONFIG_ options required to properly test this new/modified feature. Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions. Also check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed for Kbuild to compile the code statically into vmlinux. List them in the EnableConfigs output array, and DO NOT add a '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. Prompt: For your convenience, here is the diff of the changes:
commit 66b46b058899bd0f496b52d7b19133a81e81ee9b
Author: syz-cluster <triage@syzkaller.com>
Date: Mon Aug 10 12:52:35 2026 +0000
syz-cluster: applied patch under review
diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h
index 08005676702c2..2cbaa9aba901c 100644
--- a/arch/x86/kvm/vmx/common.h
+++ b/arch/x86/kvm/vmx/common.h
@@ -4,6 +4,7 @@
#include <linux/kvm_host.h>
#include <asm/posted_intr.h>
+#include <asm/vmx.h>
#include "mmu.h"
@@ -183,6 +184,24 @@ static inline void __vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu,
kvm_vcpu_trigger_posted_interrupt(vcpu, POSTED_INTR_VECTOR);
}
+static inline int __vmx_handle_notify(struct kvm_vcpu *vcpu,
+ unsigned long exit_qual)
+{
+ bool context_invalid = exit_qual & NOTIFY_VM_CONTEXT_INVALID;
+
+ ++vcpu->stat.notify_window_exits;
+
+ if (vcpu->kvm->arch.notify_vmexit_flags & KVM_X86_NOTIFY_VMEXIT_USER ||
+ context_invalid) {
+ vcpu->run->exit_reason = KVM_EXIT_NOTIFY;
+ vcpu->run->notify.flags = context_invalid ?
+ KVM_NOTIFY_CONTEXT_INVALID : 0;
+ return 0;
+ }
+
+ return 1;
+}
+
noinstr void vmx_handle_nmi(struct kvm_vcpu *vcpu);
#endif /* __KVM_X86_VMX_COMMON_H */
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index b272c20586a74..ac3f71643cd5e 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -921,10 +921,10 @@ static __always_inline u32 tdcall_to_vmx_exit_reason(struct kvm_vcpu *vcpu)
return EXIT_REASON_TDCALL;
}
-static __always_inline u32 tdx_to_vmx_exit_reason(struct kvm_vcpu *vcpu)
+static __always_inline union vmx_exit_reason tdx_to_vmx_exit_reason(struct kvm_vcpu *vcpu)
{
struct vcpu_tdx *tdx = to_tdx(vcpu);
- u32 exit_reason;
+ union vmx_exit_reason exit_reason;
switch (tdx->vp_enter_ret & TDX_SEAMCALL_STATUS_MASK) {
case TDX_SUCCESS:
@@ -934,23 +934,33 @@ static __always_inline u32 tdx_to_vmx_exit_reason(struct kvm_vcpu *vcpu)
case TDX_NON_RECOVERABLE_TD_WRONG_APIC_MODE:
break;
default:
- return -1u;
+ /*
+ * Synthesize an invalid bogus Exit Reason, as the TDX-Module
+ * never attempted to run the vCPU, i.e. the Exit Reason is
+ * undefined, but this is NOT a failed VM-Enter.
+ */
+ return (union vmx_exit_reason) {
+ .basic = -1,
+ };
}
- exit_reason = tdx->vp_enter_ret;
+ exit_reason.full = (u32)tdx->vp_enter_ret;
- switch (exit_reason) {
+ switch (exit_reason.basic) {
case EXIT_REASON_TDCALL:
if (tdvmcall_exit_type(vcpu))
- return EXIT_REASON_VMCALL;
-
- return tdcall_to_vmx_exit_reason(vcpu);
+ exit_reason.basic = EXIT_REASON_VMCALL;
+ else
+ exit_reason.basic = tdcall_to_vmx_exit_reason(vcpu);
+ break;
case EXIT_REASON_EPT_MISCONFIG:
/*
* Defer KVM_BUG_ON() until tdx_handle_exit() because this is in
* non-instrumentable code with interrupts disabled.
*/
- return -1u;
+ return (union vmx_exit_reason) {
+ .basic = -1,
+ };
default:
break;
}
@@ -967,7 +977,7 @@ static noinstr void tdx_vcpu_enter_exit(struct kvm_vcpu *vcpu)
tdx->vp_enter_ret = tdh_vp_enter(&tdx->vp, &tdx->vp_enter_args);
- vt->exit_reason.full = tdx_to_vmx_exit_reason(vcpu);
+ vt->exit_reason = tdx_to_vmx_exit_reason(vcpu);
vt->exit_qualification = tdx->vp_enter_args.rcx;
tdx->ext_exit_qualification = tdx->vp_enter_args.rdx;
@@ -981,8 +991,7 @@ static noinstr void tdx_vcpu_enter_exit(struct kvm_vcpu *vcpu)
static bool tdx_failed_vmentry(struct kvm_vcpu *vcpu)
{
- return vmx_get_exit_reason(vcpu).failed_vmentry &&
- vmx_get_exit_reason(vcpu).full != -1u;
+ return vmx_get_exit_reason(vcpu).failed_vmentry;
}
static fastpath_t tdx_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
@@ -1071,8 +1080,10 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)
* allowing vCPU entry to avoid contention with tdh_vp_enter() and
* TDCALLs.
*/
- if (unlikely(READ_ONCE(to_kvm_tdx(vcpu->kvm)->wait_for_sept_zap)))
+ if (unlikely(READ_ONCE(to_kvm_tdx(vcpu->kvm)->wait_for_sept_zap))) {
+ vt->exit_reason.bus_lock_detected = 0;
return EXIT_FASTPATH_EXIT_HANDLED;
+ }
trace_kvm_entry(vcpu, run_flags & KVM_RUN_FORCE_IMMEDIATE_EXIT);
@@ -2028,7 +2039,7 @@ int tdx_complete_emulated_msr(struct kvm_vcpu *vcpu, int err)
}
-int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
+static int __tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
{
struct vcpu_tdx *tdx = to_tdx(vcpu);
u64 vp_enter_ret = tdx->vp_enter_ret;
@@ -2126,6 +2137,11 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
* - If it's not an MSMI, no need to do anything here.
*/
return 1;
+ case EXIT_REASON_NOTIFY:
+ /* NMI blocking state is handled by TDX module */
+ return __vmx_handle_notify(vcpu, vmx_get_exit_qual(vcpu));
+ case EXIT_REASON_BUS_LOCK:
+ return handle_bus_lock_vmexit(vcpu);
default:
break;
}
@@ -2135,13 +2151,29 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
return 0;
}
+int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
+{
+ int ret = __tdx_handle_exit(vcpu, fastpath);
+
+ /* Exit to user space when bus lock was detected */
+ if (vmx_get_exit_reason(vcpu).bus_lock_detected) {
+ if (ret > 0) {
+ vcpu->run->exit_reason = KVM_EXIT_X86_BUS_LOCK;
+ ret = 0;
+ }
+
+ vcpu->run->flags |= KVM_RUN_X86_BUS_LOCK;
+ }
+ return ret;
+}
+
void tdx_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
u64 *info1, u64 *info2, u32 *intr_info, u32 *error_code)
{
struct vcpu_tdx *tdx = to_tdx(vcpu);
*reason = tdx->vt.exit_reason.full;
- if (*reason != -1u) {
+ if (tdx->vt.exit_reason.basic != -1) {
*info1 = vmx_get_exit_qual(vcpu);
*info2 = tdx->ext_exit_qualification;
*intr_info = vmx_get_intr_info(vcpu);
@@ -3154,6 +3186,17 @@ static int tdx_vcpu_init(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *cmd)
td_vmcs_write64(tdx, POSTED_INTR_DESC_ADDR, __pa(&tdx->vt.pi_desc));
td_vmcs_setbit32(tdx, PIN_BASED_VM_EXEC_CONTROL, PIN_BASED_POSTED_INTR);
+ if (kvm_notify_vmexit_enabled(vcpu->kvm)) {
+ td_vmcs_setbit32(tdx, SECONDARY_VM_EXEC_CONTROL,
+ SECONDARY_EXEC_NOTIFY_VM_EXITING);
+ td_vmcs_write32(tdx, NOTIFY_WINDOW,
+ vcpu->kvm->arch.notify_window);
+ }
+
+ if (vcpu->kvm->arch.bus_lock_detection_enabled)
+ td_vmcs_setbit32(tdx, SECONDARY_VM_EXEC_CONTROL,
+ SECONDARY_EXEC_BUS_LOCK_DETECTION);
+
tdx->state = VCPU_TD_STATE_INITIALIZED;
return 0;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index e3bfe6aca1a0e..c429db9b92057 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6265,7 +6265,7 @@ static int handle_encls(struct kvm_vcpu *vcpu)
}
#endif /* CONFIG_X86_SGX_KVM */
-static int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu)
+int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu)
{
/*
* Hardware may or may not set the BUS_LOCK_DETECTED flag on BUS_LOCK
@@ -6279,9 +6279,6 @@ static int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu)
static int handle_notify(struct kvm_vcpu *vcpu)
{
unsigned long exit_qual = vmx_get_exit_qual(vcpu);
- bool context_invalid = exit_qual & NOTIFY_VM_CONTEXT_INVALID;
-
- ++vcpu->stat.notify_window_exits;
/*
* Notify VM exit happened while executing iret from NMI,
@@ -6291,15 +6288,7 @@ static int handle_notify(struct kvm_vcpu *vcpu)
vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
GUEST_INTR_STATE_NMI);
- if (vcpu->kvm->arch.notify_vmexit_flags & KVM_X86_NOTIFY_VMEXIT_USER ||
- context_invalid) {
- vcpu->run->exit_reason = KVM_EXIT_NOTIFY;
- vcpu->run->notify.flags = context_invalid ?
- KVM_NOTIFY_CONTEXT_INVALID : 0;
- return 0;
- }
-
- return 1;
+ return __vmx_handle_notify(vcpu, exit_qual);
}
static int vmx_get_msr_imm_reg(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index dc8517f15bc46..8faf04c09721c 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -379,6 +379,7 @@ bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned int flags);
void vmx_ept_load_pdptrs(struct kvm_vcpu *vcpu);
void vmx_set_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type, bool set);
+int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu);
static inline void vmx_disable_intercept_for_msr(struct kvm_vcpu *vcpu,
u32 msr, int type)
|
| 3/2 | 2026/08/10 12:52 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 5564 output: 20 thoughts: 1555 Thoughts: **My Assessment of the KVM TDX Patch's Fuzzability** Okay, let's break this down. I'm looking at a patch that's making changes to KVM TDX code, specifically in `arch/x86/kvm/vmx/tdx.c`, `arch/x86/kvm/vmx/vmx.c`, and related headers. It seems like the core of the patch is about handling `EXIT_REASON_NOTIFY` and `EXIT_REASON_BUS_LOCK` in TDX and also refactoring `tdx_to_vmx_exit_reason`. I need to decide if this warrants fuzzing effort. First, I need to understand if this TDX code is even *reachable* in a typical fuzzing environment. My gut reaction is that TDX requires specific Intel hardware with Trust Domain Extensions, and that throws up a red flag. Standard QEMU or GCE instances might *not* have that hardware enabled. Specifically, I'm thinking about whether syzkaller can use this. Syzkaller heavily uses `/dev/kvm`. If the host doesn't support TDX, `KVM_CAP_VM_TYPES` won't advertise it, and creating a VM with TDX will fail. The prompt specifically mentions that code paths unreachable in virtualized environments like GCE or QEMU should be flagged as not worth fuzzing. Okay, so hardware requirements are an issue here. Nested TDX is not supported yet or requires hardware support. However, the patch *also* touches `vmx.c`, and I know that VMX is heavily fuzzed. It looks like it's refactoring code to extract `__vmx_handle_notify` and `handle_bus_lock_vmexit` to be used in both `vmx.c` and `tdx.c`. This is where it gets interesting. I need to make sure this code is not fundamentally changed in a way that allows us to target it in standard environments. I dug into the changes in `vmx.c`. It looks like `handle_bus_lock_vmexit` is just changing its linkage from static to global. Also, the `handle_notify` function in `vmx.c` is being refactored. The logic is moved to `__vmx_handle_notify` in `common.h`. So, there are no *functional* changes in the standard VMX code. This is purely refactoring to share code with TDX. This means the functional changes are mainly in `tdx.c` where the new functionality for `EXIT_REASON_NOTIFY` and `EXIT_REASON_BUS_LOCK` are implemented, along with refactoring `tdx_to_vmx_exit_reason`. The critical question is, can we fuzz the *TDX* parts? I'm pretty sure that standard environments won't support it because it's hardware-dependent. GCE *does* have TDX instances, like C3 instances, but standard syzkaller environments usually run on generic instances or QEMU without TDX hardware. TDX relies on the TDX module (SEAM) and hardware encryption and cannot be emulated in software. I need to confirm if `tdx_handle_exit` is reachable. I will search for usages of `tdx_handle_exit` and `tdx_to_vmx_exit_reason`. I'm going to look at the surrounding code to determine how those exit reasons are triggered. |
| 4/2 | 2026/08/10 12:52 | tool | grepper |
0mArgs:{
"Expression": "tdx_handle_exit"
}Results: {
"Output": "arch/x86/kvm/vmx/main.c=157=static int vt_handle_exit(struct kvm_vcpu *vcpu,\n--\narch/x86/kvm/vmx/main.c-160-\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c:161:\t\treturn tdx_handle_exit(vcpu, fastpath);\narch/x86/kvm/vmx/main.c-162-\n--\narch/x86/kvm/vmx/tdx.c=924=static __always_inline union vmx_exit_reason tdx_to_vmx_exit_reason(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/tdx.c-957-\t\t/*\narch/x86/kvm/vmx/tdx.c:958:\t\t * Defer KVM_BUG_ON() until tdx_handle_exit() because this is in\narch/x86/kvm/vmx/tdx.c-959-\t\t * non-instrumentable code with interrupts disabled.\n--\narch/x86/kvm/vmx/tdx.c=1143=static int tdx_handle_exception_nmi(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/tdx.c-1148-\t * Machine checks are handled by handle_exception_irqoff(), or by\narch/x86/kvm/vmx/tdx.c:1149:\t * tdx_handle_exit() with TDX_NON_RECOVERABLE set if a #MC occurs on\narch/x86/kvm/vmx/tdx.c-1150-\t * VM-Entry. NMIs are handled by tdx_vcpu_enter_exit().\n--\narch/x86/kvm/vmx/tdx.c=2028=int tdx_complete_emulated_msr(struct kvm_vcpu *vcpu, int err)\n--\narch/x86/kvm/vmx/tdx.c-2041-\narch/x86/kvm/vmx/tdx.c:2042:static int __tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)\narch/x86/kvm/vmx/tdx.c-2043-{\n--\narch/x86/kvm/vmx/tdx.c-2153-\narch/x86/kvm/vmx/tdx.c:2154:int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)\narch/x86/kvm/vmx/tdx.c-2155-{\narch/x86/kvm/vmx/tdx.c:2156:\tint ret = __tdx_handle_exit(vcpu, fastpath);\narch/x86/kvm/vmx/tdx.c-2157-\n--\narch/x86/kvm/vmx/x86_ops.h=143=void tdx_vcpu_put(struct kvm_vcpu *vcpu);\narch/x86/kvm/vmx/x86_ops.h:144:int tdx_handle_exit(struct kvm_vcpu *vcpu,\narch/x86/kvm/vmx/x86_ops.h-145-\t\tenum exit_fastpath_completion fastpath);\n"
} |
| 5/2 | 2026/08/10 12:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 8819 output: 20 thoughts: 59 Thoughts: **Analyzing the TD vCPU Exit Handling** Okay, so I'm looking at how we handle exits related to TD virtual CPUs. Specifically, the `tdx_handle_exit` function gets called from `vt_handle_exit`, but only if the CPU in question (`vcpu`) is, in fact, a TD vCPU. The interesting point I'm focusing on now is whether or not we can create a TD vCPU in an environment where the underlying hardware doesn't offer the necessary support. It makes me curious about the assumptions baked into the design. To answer this question, and clarify the circumstances in which these functions are called, I should re-examine the `is_td_vcpu` function to understand precisely how it determines if a CPU is a TD vCPU. This will tell me whether the logic covers the possibility of a TD vCPU without hardware support. |
| 6/2 | 2026/08/10 12:53 | tool | grepper |
0mArgs:{
"Expression": "is_td_vcpu"
}Results: {
"Output": "arch/x86/kvm/vmx/common.h=61=static __always_inline bool is_td(struct kvm *kvm)\n--\narch/x86/kvm/vmx/common.h-65-\narch/x86/kvm/vmx/common.h:66:static __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/common.h-67-{\n--\narch/x86/kvm/vmx/common.h=73=static __always_inline bool is_td(struct kvm *kvm) { return false; }\narch/x86/kvm/vmx/common.h:74:static __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu) { return false; }\narch/x86/kvm/vmx/common.h-75-\n--\narch/x86/kvm/vmx/main.c=73=static int vt_vcpu_create(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-74-{\narch/x86/kvm/vmx/main.c:75:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-76-\t\treturn tdx_vcpu_create(vcpu);\n--\narch/x86/kvm/vmx/main.c=81=static void vt_vcpu_free(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-82-{\narch/x86/kvm/vmx/main.c:83:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-84-\t\ttdx_vcpu_free(vcpu);\n--\narch/x86/kvm/vmx/main.c=91=static void vt_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)\narch/x86/kvm/vmx/main.c-92-{\narch/x86/kvm/vmx/main.c:93:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-94-\t\ttdx_vcpu_reset(vcpu, init_event);\n--\narch/x86/kvm/vmx/main.c=101=static void vt_vcpu_load(struct kvm_vcpu *vcpu, int cpu)\narch/x86/kvm/vmx/main.c-102-{\narch/x86/kvm/vmx/main.c:103:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-104-\t\ttdx_vcpu_load(vcpu, cpu);\n--\narch/x86/kvm/vmx/main.c=111=static void vt_update_cpu_dirty_logging(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-116-\t */\narch/x86/kvm/vmx/main.c:117:\tif (WARN_ON_ONCE(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/main.c-118-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=123=static void vt_prepare_switch_to_guest(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-124-{\narch/x86/kvm/vmx/main.c:125:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-126-\t\ttdx_prepare_switch_to_guest(vcpu);\n--\narch/x86/kvm/vmx/main.c=133=static void vt_vcpu_put(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-134-{\narch/x86/kvm/vmx/main.c:135:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-136-\t\ttdx_vcpu_put(vcpu);\n--\narch/x86/kvm/vmx/main.c=143=static bool vt_vcpu_needs_initialization(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-144-{\narch/x86/kvm/vmx/main.c:145:\treturn is_td_vcpu(vcpu) \u0026\u0026\narch/x86/kvm/vmx/main.c-146-\t tdx_vcpu_needs_initialization(vcpu);\n--\narch/x86/kvm/vmx/main.c=149=static fastpath_t vt_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)\narch/x86/kvm/vmx/main.c-150-{\narch/x86/kvm/vmx/main.c:151:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-152-\t\treturn tdx_vcpu_run(vcpu, run_flags);\n--\narch/x86/kvm/vmx/main.c=157=static int vt_handle_exit(struct kvm_vcpu *vcpu,\n--\narch/x86/kvm/vmx/main.c-159-{\narch/x86/kvm/vmx/main.c:160:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-161-\t\treturn tdx_handle_exit(vcpu, fastpath);\n--\narch/x86/kvm/vmx/main.c=166=static bool vt_unhandleable_emulation_required(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-167-{\narch/x86/kvm/vmx/main.c:168:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-169-\t\tWARN_ON_ONCE(to_vt(vcpu)-\u003eemulation_required);\n--\narch/x86/kvm/vmx/main.c=176=static int vt_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)\narch/x86/kvm/vmx/main.c-177-{\narch/x86/kvm/vmx/main.c:178:\tif (unlikely(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/main.c-179-\t\treturn tdx_set_msr(vcpu, msr_info);\n--\narch/x86/kvm/vmx/main.c=196=static int vt_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)\narch/x86/kvm/vmx/main.c-197-{\narch/x86/kvm/vmx/main.c:198:\tif (unlikely(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/main.c-199-\t\treturn tdx_get_msr(vcpu, msr_info);\n--\narch/x86/kvm/vmx/main.c=204=static void vt_recalc_intercepts(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-211-\t */\narch/x86/kvm/vmx/main.c:212:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-213-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=218=static int vt_complete_emulated_msr(struct kvm_vcpu *vcpu, int err)\narch/x86/kvm/vmx/main.c-219-{\narch/x86/kvm/vmx/main.c:220:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-221-\t\treturn tdx_complete_emulated_msr(vcpu, err);\n--\narch/x86/kvm/vmx/main.c=227=static int vt_smi_allowed(struct kvm_vcpu *vcpu, bool for_injection)\narch/x86/kvm/vmx/main.c-228-{\narch/x86/kvm/vmx/main.c:229:\tif (KVM_BUG_ON(is_td_vcpu(vcpu), vcpu-\u003ekvm))\narch/x86/kvm/vmx/main.c-230-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=235=static int vt_enter_smm(struct kvm_vcpu *vcpu, union kvm_smram *smram)\narch/x86/kvm/vmx/main.c-236-{\narch/x86/kvm/vmx/main.c:237:\tif (KVM_BUG_ON(is_td_vcpu(vcpu), vcpu-\u003ekvm))\narch/x86/kvm/vmx/main.c-238-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=243=static int vt_leave_smm(struct kvm_vcpu *vcpu, const union kvm_smram *smram)\narch/x86/kvm/vmx/main.c-244-{\narch/x86/kvm/vmx/main.c:245:\tif (KVM_BUG_ON(is_td_vcpu(vcpu), vcpu-\u003ekvm))\narch/x86/kvm/vmx/main.c-246-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=251=static void vt_enable_smi_window(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-252-{\narch/x86/kvm/vmx/main.c:253:\tif (KVM_BUG_ON(is_td_vcpu(vcpu), vcpu-\u003ekvm))\narch/x86/kvm/vmx/main.c-254-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=261=static int vt_check_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type,\n--\narch/x86/kvm/vmx/main.c-270-\t */\narch/x86/kvm/vmx/main.c:271:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-272-\t\treturn X86EMUL_RETRY_INSTR;\n--\narch/x86/kvm/vmx/main.c=277=static bool vt_apic_init_signal_blocked(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-282-\t */\narch/x86/kvm/vmx/main.c:283:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-284-\t\treturn true;\n--\narch/x86/kvm/vmx/main.c=289=static void vt_set_virtual_apic_mode(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-291-\t/* Only x2APIC mode is supported for TD. */\narch/x86/kvm/vmx/main.c:292:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-293-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=298=static void vt_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)\narch/x86/kvm/vmx/main.c-299-{\narch/x86/kvm/vmx/main.c:300:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-301-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=306=static int vt_sync_pir_to_irr(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-307-{\narch/x86/kvm/vmx/main.c:308:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-309-\t\treturn -1;\n--\narch/x86/kvm/vmx/main.c=314=static void vt_deliver_interrupt(struct kvm_lapic *apic, int delivery_mode,\n--\narch/x86/kvm/vmx/main.c-316-{\narch/x86/kvm/vmx/main.c:317:\tif (is_td_vcpu(apic-\u003evcpu)) {\narch/x86/kvm/vmx/main.c-318-\t\ttdx_deliver_interrupt(apic, delivery_mode, trig_mode,\n--\narch/x86/kvm/vmx/main.c=326=static void vt_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-327-{\narch/x86/kvm/vmx/main.c:328:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-329-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=334=static void vt_update_exception_bitmap(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-335-{\narch/x86/kvm/vmx/main.c:336:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-337-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=342=static u64 vt_get_segment_base(struct kvm_vcpu *vcpu, int seg)\narch/x86/kvm/vmx/main.c-343-{\narch/x86/kvm/vmx/main.c:344:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-345-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=350=static void vt_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var,\n--\narch/x86/kvm/vmx/main.c-352-{\narch/x86/kvm/vmx/main.c:353:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-354-\t\tmemset(var, 0, sizeof(*var));\n--\narch/x86/kvm/vmx/main.c=361=static void vt_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var,\n--\narch/x86/kvm/vmx/main.c-363-{\narch/x86/kvm/vmx/main.c:364:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-365-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=370=static int vt_get_cpl(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-371-{\narch/x86/kvm/vmx/main.c:372:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-373-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=378=static int vt_get_cpl_no_cache(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-379-{\narch/x86/kvm/vmx/main.c:380:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-381-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=386=static void vt_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)\narch/x86/kvm/vmx/main.c-387-{\narch/x86/kvm/vmx/main.c:388:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-389-\t\t*db = 0;\n--\narch/x86/kvm/vmx/main.c=397=static bool vt_is_valid_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)\narch/x86/kvm/vmx/main.c-398-{\narch/x86/kvm/vmx/main.c:399:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-400-\t\treturn true;\n--\narch/x86/kvm/vmx/main.c=405=static void vt_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)\narch/x86/kvm/vmx/main.c-406-{\narch/x86/kvm/vmx/main.c:407:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-408-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=413=static bool vt_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)\narch/x86/kvm/vmx/main.c-414-{\narch/x86/kvm/vmx/main.c:415:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-416-\t\treturn true;\n--\narch/x86/kvm/vmx/main.c=421=static void vt_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)\narch/x86/kvm/vmx/main.c-422-{\narch/x86/kvm/vmx/main.c:423:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-424-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=429=static int vt_set_efer(struct kvm_vcpu *vcpu, u64 efer)\narch/x86/kvm/vmx/main.c-430-{\narch/x86/kvm/vmx/main.c:431:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-432-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=437=static void vt_get_idt(struct kvm_vcpu *vcpu, struct desc_ptr *dt)\narch/x86/kvm/vmx/main.c-438-{\narch/x86/kvm/vmx/main.c:439:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-440-\t\tmemset(dt, 0, sizeof(*dt));\n--\narch/x86/kvm/vmx/main.c=447=static void vt_set_idt(struct kvm_vcpu *vcpu, struct desc_ptr *dt)\narch/x86/kvm/vmx/main.c-448-{\narch/x86/kvm/vmx/main.c:449:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-450-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=455=static void vt_get_gdt(struct kvm_vcpu *vcpu, struct desc_ptr *dt)\narch/x86/kvm/vmx/main.c-456-{\narch/x86/kvm/vmx/main.c:457:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-458-\t\tmemset(dt, 0, sizeof(*dt));\n--\narch/x86/kvm/vmx/main.c=465=static void vt_set_gdt(struct kvm_vcpu *vcpu, struct desc_ptr *dt)\narch/x86/kvm/vmx/main.c-466-{\narch/x86/kvm/vmx/main.c:467:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-468-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=473=static void vt_set_dr7(struct kvm_vcpu *vcpu, unsigned long val)\narch/x86/kvm/vmx/main.c-474-{\narch/x86/kvm/vmx/main.c:475:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-476-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=481=static void vt_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-487-\t */\narch/x86/kvm/vmx/main.c:488:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-489-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=494=static void vt_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)\narch/x86/kvm/vmx/main.c-495-{\narch/x86/kvm/vmx/main.c:496:\tif (WARN_ON_ONCE(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/main.c-497-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=502=static unsigned long vt_get_rflags(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-503-{\narch/x86/kvm/vmx/main.c:504:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-505-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=510=static void vt_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)\narch/x86/kvm/vmx/main.c-511-{\narch/x86/kvm/vmx/main.c:512:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-513-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=518=static bool vt_get_if_flag(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-519-{\narch/x86/kvm/vmx/main.c:520:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-521-\t\treturn false;\n--\narch/x86/kvm/vmx/main.c=526=static void vt_flush_tlb_all(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-527-{\narch/x86/kvm/vmx/main.c:528:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-529-\t\ttdx_flush_tlb_all(vcpu);\n--\narch/x86/kvm/vmx/main.c=536=static void vt_flush_tlb_current(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-537-{\narch/x86/kvm/vmx/main.c:538:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-539-\t\ttdx_flush_tlb_current(vcpu);\n--\narch/x86/kvm/vmx/main.c=546=static void vt_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr)\narch/x86/kvm/vmx/main.c-547-{\narch/x86/kvm/vmx/main.c:548:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-549-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=554=static void vt_flush_tlb_guest(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-555-{\narch/x86/kvm/vmx/main.c:556:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-557-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=562=static void vt_inject_nmi(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-563-{\narch/x86/kvm/vmx/main.c:564:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-565-\t\ttdx_inject_nmi(vcpu);\n--\narch/x86/kvm/vmx/main.c=572=static int vt_nmi_allowed(struct kvm_vcpu *vcpu, bool for_injection)\n--\narch/x86/kvm/vmx/main.c-577-\t */\narch/x86/kvm/vmx/main.c:578:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-579-\t\treturn true;\n--\narch/x86/kvm/vmx/main.c=584=static bool vt_get_nmi_mask(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-589-\t */\narch/x86/kvm/vmx/main.c:590:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-591-\t\treturn false;\n--\narch/x86/kvm/vmx/main.c=596=static void vt_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)\narch/x86/kvm/vmx/main.c-597-{\narch/x86/kvm/vmx/main.c:598:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-599-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=604=static void vt_enable_nmi_window(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-606-\t/* Refer to the comments in tdx_inject_nmi(). */\narch/x86/kvm/vmx/main.c:607:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-608-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=613=static void vt_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,\n--\narch/x86/kvm/vmx/main.c-615-{\narch/x86/kvm/vmx/main.c:616:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-617-\t\ttdx_load_mmu_pgd(vcpu, root_hpa, pgd_level);\n--\narch/x86/kvm/vmx/main.c=624=static void vt_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)\narch/x86/kvm/vmx/main.c-625-{\narch/x86/kvm/vmx/main.c:626:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-627-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=632=static u32 vt_get_interrupt_shadow(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-633-{\narch/x86/kvm/vmx/main.c:634:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-635-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=640=static void vt_patch_hypercall(struct kvm_vcpu *vcpu,\n--\narch/x86/kvm/vmx/main.c-646-\t */\narch/x86/kvm/vmx/main.c:647:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-648-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=653=static void vt_inject_irq(struct kvm_vcpu *vcpu, bool reinjected)\narch/x86/kvm/vmx/main.c-654-{\narch/x86/kvm/vmx/main.c:655:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-656-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=661=static void vt_inject_exception(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-662-{\narch/x86/kvm/vmx/main.c:663:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-664-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=669=static void vt_cancel_injection(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-670-{\narch/x86/kvm/vmx/main.c:671:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-672-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=677=static int vt_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection)\narch/x86/kvm/vmx/main.c-678-{\narch/x86/kvm/vmx/main.c:679:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-680-\t\treturn tdx_interrupt_allowed(vcpu);\n--\narch/x86/kvm/vmx/main.c=685=static void vt_enable_irq_window(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-686-{\narch/x86/kvm/vmx/main.c:687:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-688-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=693=static void vt_get_entry_info(struct kvm_vcpu *vcpu, u32 *intr_info, u32 *error_code)\n--\narch/x86/kvm/vmx/main.c-697-\narch/x86/kvm/vmx/main.c:698:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-699-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=704=static void vt_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,\n--\narch/x86/kvm/vmx/main.c-706-{\narch/x86/kvm/vmx/main.c:707:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-708-\t\ttdx_get_exit_info(vcpu, reason, info1, info2, intr_info,\n--\narch/x86/kvm/vmx/main.c=716=static void vt_update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)\narch/x86/kvm/vmx/main.c-717-{\narch/x86/kvm/vmx/main.c:718:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-719-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=724=static void vt_set_apic_access_page_addr(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-725-{\narch/x86/kvm/vmx/main.c:726:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-727-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=732=static void vt_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-733-{\narch/x86/kvm/vmx/main.c:734:\tif (is_td_vcpu(vcpu)) {\narch/x86/kvm/vmx/main.c-735-\t\tKVM_BUG_ON(!kvm_vcpu_apicv_active(vcpu), vcpu-\u003ekvm);\n--\narch/x86/kvm/vmx/main.c=742=static void vt_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)\narch/x86/kvm/vmx/main.c-743-{\narch/x86/kvm/vmx/main.c:744:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-745-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=774=static u64 vt_get_l2_tsc_offset(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-776-\t/* TDX doesn't support L2 guest at the moment. */\narch/x86/kvm/vmx/main.c:777:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-778-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=783=static u64 vt_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-785-\t/* TDX doesn't support L2 guest at the moment. */\narch/x86/kvm/vmx/main.c:786:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-787-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=792=static void vt_write_tsc_offset(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-794-\t/* In TDX, tsc offset can't be changed. */\narch/x86/kvm/vmx/main.c:795:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-796-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=801=static void vt_write_tsc_multiplier(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-803-\t/* In TDX, tsc multiplier can't be changed. */\narch/x86/kvm/vmx/main.c:804:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-805-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=811=static int vt_set_hv_timer(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc,\n--\narch/x86/kvm/vmx/main.c-814-\t/* VMX-preemption timer isn't available for TDX. */\narch/x86/kvm/vmx/main.c:815:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-816-\t\treturn -EINVAL;\n--\narch/x86/kvm/vmx/main.c=821=static void vt_cancel_hv_timer(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-823-\t/* VMX-preemption timer can't be set. See vt_set_hv_timer(). */\narch/x86/kvm/vmx/main.c:824:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-825-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=831=static void vt_setup_mce(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/main.c-832-{\narch/x86/kvm/vmx/main.c:833:\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-834-\t\treturn;\n--\narch/x86/kvm/vmx/main.c=847=static int vt_vcpu_mem_enc_ioctl(struct kvm_vcpu *vcpu, void __user *argp)\narch/x86/kvm/vmx/main.c-848-{\narch/x86/kvm/vmx/main.c:849:\tif (!is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-850-\t\treturn -EINVAL;\n--\narch/x86/kvm/vmx/main.c=855=static int vt_vcpu_mem_enc_unlocked_ioctl(struct kvm_vcpu *vcpu, void __user *argp)\narch/x86/kvm/vmx/main.c-856-{\narch/x86/kvm/vmx/main.c:857:\tif (!is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c-858-\t\treturn -EINVAL;\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=209=static bool vmx_needs_pi_wakeup(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/posted_intr.c-218-\t */\narch/x86/kvm/vmx/posted_intr.c:219:\treturn (vmx_can_use_ipiv(vcpu) \u0026\u0026 !is_td_vcpu(vcpu)) ||\narch/x86/kvm/vmx/posted_intr.c-220-\t\tvmx_can_use_vtd_pi(vcpu-\u003ekvm);\n--\narch/x86/kvm/vmx/posted_intr.c=223=void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/posted_intr.c-242-\tif (!vcpu-\u003epreempted \u0026\u0026 kvm_vcpu_is_blocking(vcpu) \u0026\u0026\narch/x86/kvm/vmx/posted_intr.c:243:\t ((is_td_vcpu(vcpu) \u0026\u0026 tdx_interrupt_allowed(vcpu)) ||\narch/x86/kvm/vmx/posted_intr.c:244:\t (!is_td_vcpu(vcpu) \u0026\u0026 !vmx_interrupt_blocked(vcpu))))\narch/x86/kvm/vmx/posted_intr.c-245-\t\tpi_enable_wakeup_handler(vcpu);\n--\narch/x86/kvm/vmx/vmx.h=322=static __always_inline unsigned long vmx_get_exit_qual(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/vmx.h-326-\tif (!kvm_register_test_and_mark_available(vcpu, VCPU_REG_EXIT_INFO_1) \u0026\u0026\narch/x86/kvm/vmx/vmx.h:327:\t !WARN_ON_ONCE(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/vmx.h-328-\t\tvt-\u003eexit_qualification = vmcs_readl(EXIT_QUALIFICATION);\n--\narch/x86/kvm/vmx/vmx.h=333=static __always_inline u32 vmx_get_intr_info(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/vmx.h-337-\tif (!kvm_register_test_and_mark_available(vcpu, VCPU_REG_EXIT_INFO_2) \u0026\u0026\narch/x86/kvm/vmx/vmx.h:338:\t !WARN_ON_ONCE(is_td_vcpu(vcpu)))\narch/x86/kvm/vmx/vmx.h-339-\t\tvt-\u003eexit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);\n"
} |
| 7/2 | 2026/08/10 12:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 21510 output: 21 thoughts: 47 Thoughts: **Analyzing TDX vCPU Creation** Okay, so I'm looking at this `is_td_vcpu` function, and it seems pretty straightforward – it's identifying if a vCPU is running within a TDX environment. My immediate question, though, is whether or not it's actually *possible* to conjure up a TDX vCPU without underlying hardware support. We're talking about the fundamental architecture here, so it seems like a crucial point to understand. To get a handle on this, I need to dive into how these vCPUs are actually constructed. The natural next step is to examine the `tdx_vcpu_create` function. I need to understand its behavior, its requirements, and its error conditions. Does it strictly enforce a TDX hardware check? Does it offer any leeway or fallback mechanisms? The answers to these questions are going to clarify if we can run TDX code without having a supporting platform. |
| 8/2 | 2026/08/10 12:53 | tool | grepper |
0mArgs:{
"Expression": "tdx_vcpu_create"
}Results: {
"Output": "arch/x86/kvm/vmx/main.c=73=static int vt_vcpu_create(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/main.c-75-\tif (is_td_vcpu(vcpu))\narch/x86/kvm/vmx/main.c:76:\t\treturn tdx_vcpu_create(vcpu);\narch/x86/kvm/vmx/main.c-77-\n--\narch/x86/kvm/vmx/tdx.c=618=int tdx_vm_init(struct kvm *kvm)\n--\narch/x86/kvm/vmx/tdx.c-667-\narch/x86/kvm/vmx/tdx.c:668:int tdx_vcpu_create(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/tdx.c-669-{\n--\narch/x86/kvm/vmx/tdx.c=827=void tdx_vcpu_put(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/vmx/tdx.c-841- * 3. KVM_CREATE_VCPU ioctl. (only when TD is TD_STATE_INITIALIZED).\narch/x86/kvm/vmx/tdx.c:842: * 3.1 tdx_vcpu_create() transitions vCPU state to VCPU_TD_STATE_UNINITIALIZED.\narch/x86/kvm/vmx/tdx.c-843- * 3.2 vcpu_load() and vcpu_put() in kvm_arch_vcpu_create().\n--\narch/x86/kvm/vmx/x86_ops.h=134=int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);\narch/x86/kvm/vmx/x86_ops.h-135-\narch/x86/kvm/vmx/x86_ops.h:136:int tdx_vcpu_create(struct kvm_vcpu *vcpu);\narch/x86/kvm/vmx/x86_ops.h-137-void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event);\n"
} |
| 9/2 | 2026/08/10 12:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 22401 output: 20 thoughts: 46 Thoughts: Okay, let's break this down. **Initial Assessment of TDX Initialization** My initial thought is to zero in on the `tdx_vm_init` function. That's the key. I need to understand how TDX is actually enabled. The critical point is whether or not TDX enablement is contingent on underlying hardware capabilities. My reasoning here is straightforward: if `tdx_vm_init` relies on specific hardware features—in this case, for TDX support—then the function should fail gracefully when those features aren't present. A successful initialization hinges on the platform's support for the required technologies. Therefore, a failure of this function acts as an excellent indicator of missing TDX hardware support. |
| 10/2 | 2026/08/10 12:53 | tool | grepper |
0mArgs:{
"Expression": "tdx_vm_init"
}Results: {
"Output": "arch/x86/kvm/vmx/main.c=43=static int vt_vm_init(struct kvm *kvm)\n--\narch/x86/kvm/vmx/main.c-45-\tif (is_td(kvm))\narch/x86/kvm/vmx/main.c:46:\t\treturn tdx_vm_init(kvm);\narch/x86/kvm/vmx/main.c-47-\n--\narch/x86/kvm/vmx/tdx.c=605=static int tdx_do_tdh_mng_key_config(void *param)\n--\narch/x86/kvm/vmx/tdx.c-617-\narch/x86/kvm/vmx/tdx.c:618:int tdx_vm_init(struct kvm *kvm)\narch/x86/kvm/vmx/tdx.c-619-{\n--\narch/x86/kvm/vmx/x86_ops.h=130=void tdx_disable_virtualization_cpu(void);\narch/x86/kvm/vmx/x86_ops.h:131:int tdx_vm_init(struct kvm *kvm);\narch/x86/kvm/vmx/x86_ops.h-132-void tdx_mmu_release_hkid(struct kvm *kvm);\n"
} |
| 11/2 | 2026/08/10 12:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 23001 output: 44 thoughts: 32 Thoughts: Here's my analysis of the provided text, rendered as though I were thinking through it: **Diving into TDX Initialization** Alright, let's get down to brass tacks. I need to understand the TDX (Trusted Domain Extension) initialization process within KVM on x86. The logical starting point is the `tdx_vm_init` function, and that's exactly where I'll be digging in. So, I'll be navigating to `arch/x86/kvm/vmx/tdx.c` to see how this all comes together. Understanding how the VM is set up for TDX is critical to everything else, so this is where I start. |
| 12/2 | 2026/08/10 12:53 | tool | read-file |
0mArgs:{
"File": "arch/x86/kvm/vmx/tdx.c",
"FirstLine": 618,
"LineCount": 50
}Results: {
"Contents": " 618:\tint tdx_vm_init(struct kvm *kvm)\n 619:\t{\n 620:\t\tstruct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);\n 621:\t\n 622:\t\tkvm-\u003earch.has_protected_state = true;\n 623:\t\t/*\n 624:\t\t * TDX Module doesn't allow the hypervisor to modify the EOI-bitmap,\n 625:\t\t * i.e. all EOIs are accelerated and never trigger exits.\n 626:\t\t */\n 627:\t\tkvm-\u003earch.has_protected_eoi = true;\n 628:\t\tkvm-\u003earch.has_private_mem = true;\n 629:\t\tkvm-\u003earch.disabled_quirks |= KVM_X86_QUIRK_IGNORE_GUEST_PAT;\n 630:\t\n 631:\t\t/*\n 632:\t\t * PMU support is provided by the TDX-Module (if enabled for the VM).\n 633:\t\t * From KVM's perspective, the VM doesn't have a virtual PMU.\n 634:\t\t */\n 635:\t\tkvm-\u003earch.has_protected_pmu = true;\n 636:\t\n 637:\t\t/*\n 638:\t\t * Because guest TD is protected, VMM can't parse the instruction in TD.\n 639:\t\t * Instead, guest uses MMIO hypercall. For unmodified device driver,\n 640:\t\t * #VE needs to be injected for MMIO and #VE handler in TD converts MMIO\n 641:\t\t * instruction into MMIO hypercall.\n 642:\t\t *\n 643:\t\t * SPTE value for MMIO needs to be setup so that #VE is injected into\n 644:\t\t * TD instead of triggering EPT MISCONFIG.\n 645:\t\t * - RWX=0 so that EPT violation is triggered.\n 646:\t\t * - suppress #VE bit is cleared to inject #VE.\n 647:\t\t */\n 648:\t\tkvm_mmu_set_mmio_spte_value(kvm, 0);\n 649:\t\n 650:\t\t/*\n 651:\t\t * TDX has its own limit of maximum vCPUs it can support for all\n 652:\t\t * TDX guests in addition to KVM_MAX_VCPUS. TDX module reports\n 653:\t\t * such limit via the MAX_VCPU_PER_TD global metadata. In\n 654:\t\t * practice, it reflects the number of logical CPUs that ALL\n 655:\t\t * platforms that the TDX module supports can possibly have.\n 656:\t\t *\n 657:\t\t * Limit TDX guest's maximum vCPUs to the number of logical CPUs\n 658:\t\t * the platform has. Simply forwarding the MAX_VCPU_PER_TD to\n 659:\t\t * userspace would result in an unpredictable ABI.\n 660:\t\t */\n 661:\t\tkvm-\u003emax_vcpus = min_t(int, kvm-\u003emax_vcpus, num_present_cpus());\n 662:\t\n 663:\t\tkvm_tdx-\u003estate = TD_STATE_UNINITIALIZED;\n 664:\t\n 665:\t\treturn 0;\n 666:\t}\n 667:\t\n"
} |
| 13/2 | 2026/08/10 12:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 24109 output: 18 thoughts: 32 Thoughts: Okay, here's my interpretation of those thoughts, tailored for an expert audience, presented in the first person: **Initial TDX VM Initialization Concern** Hmm, so `tdx_vm_init`… wait a second, it doesn't seem to explicitly verify the underlying hardware's support for TDX, does it? That feels like a potential oversight. We need to be absolutely certain before going down this path. I can't just assume the platform will handle it. Alright, the next step is definitely to immediately check how `is_td(kvm)` works and what checks it includes. That function should be the gatekeeper, making sure we have the necessary hardware capabilities before anything else. The whole setup depends on that, so I'm focusing my attention there now to ensure everything is initialized correctly. |
| 14/2 | 2026/08/10 12:53 | tool | grepper |
0mArgs:{
"Expression": "is_td\\("
}Results: {
"Output": "arch/x86/kvm/vmx/common.h=34=struct vcpu_vt {\n--\narch/x86/kvm/vmx/common.h-60-\narch/x86/kvm/vmx/common.h:61:static __always_inline bool is_td(struct kvm *kvm)\narch/x86/kvm/vmx/common.h-62-{\n--\narch/x86/kvm/vmx/common.h=66=static __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu)\narch/x86/kvm/vmx/common.h-67-{\narch/x86/kvm/vmx/common.h:68:\treturn is_td(vcpu-\u003ekvm);\narch/x86/kvm/vmx/common.h-69-}\n--\narch/x86/kvm/vmx/common.h-72-\narch/x86/kvm/vmx/common.h:73:static __always_inline bool is_td(struct kvm *kvm) { return false; }\narch/x86/kvm/vmx/common.h-74-static __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu) { return false; }\n--\narch/x86/kvm/vmx/main.c=43=static int vt_vm_init(struct kvm *kvm)\narch/x86/kvm/vmx/main.c-44-{\narch/x86/kvm/vmx/main.c:45:\tif (is_td(kvm))\narch/x86/kvm/vmx/main.c-46-\t\treturn tdx_vm_init(kvm);\n--\narch/x86/kvm/vmx/main.c=51=static void vt_vm_pre_destroy(struct kvm *kvm)\narch/x86/kvm/vmx/main.c-52-{\narch/x86/kvm/vmx/main.c:53:\tif (is_td(kvm))\narch/x86/kvm/vmx/main.c-54-\t\treturn tdx_mmu_release_hkid(kvm);\n--\narch/x86/kvm/vmx/main.c=57=static void vt_vm_destroy(struct kvm *kvm)\narch/x86/kvm/vmx/main.c-58-{\narch/x86/kvm/vmx/main.c:59:\tif (is_td(kvm))\narch/x86/kvm/vmx/main.c-60- return tdx_vm_destroy(kvm);\n--\narch/x86/kvm/vmx/main.c=65=static int vt_vcpu_precreate(struct kvm *kvm)\narch/x86/kvm/vmx/main.c-66-{\narch/x86/kvm/vmx/main.c:67:\tif (is_td(kvm))\narch/x86/kvm/vmx/main.c-68-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=188=static bool vt_has_emulated_msr(struct kvm *kvm, u32 index)\narch/x86/kvm/vmx/main.c-189-{\narch/x86/kvm/vmx/main.c:190:\tif (kvm \u0026\u0026 is_td(kvm))\narch/x86/kvm/vmx/main.c-191-\t\treturn tdx_has_emulated_msr(index);\n--\narch/x86/kvm/vmx/main.c=750=static int vt_set_tss_addr(struct kvm *kvm, unsigned int addr)\narch/x86/kvm/vmx/main.c-751-{\narch/x86/kvm/vmx/main.c:752:\tif (is_td(kvm))\narch/x86/kvm/vmx/main.c-753-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=758=static int vt_set_identity_map_addr(struct kvm *kvm, u64 ident_addr)\narch/x86/kvm/vmx/main.c-759-{\narch/x86/kvm/vmx/main.c:760:\tif (is_td(kvm))\narch/x86/kvm/vmx/main.c-761-\t\treturn 0;\n--\narch/x86/kvm/vmx/main.c=766=static bool vt_tdp_has_smep(struct kvm *kvm)\narch/x86/kvm/vmx/main.c-767-{\narch/x86/kvm/vmx/main.c:768:\tif (is_td(kvm))\narch/x86/kvm/vmx/main.c-769-\t\treturn false;\n--\narch/x86/kvm/vmx/main.c=839=static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)\narch/x86/kvm/vmx/main.c-840-{\narch/x86/kvm/vmx/main.c:841:\tif (!is_td(kvm))\narch/x86/kvm/vmx/main.c-842-\t\treturn -ENOTTY;\n--\narch/x86/kvm/vmx/main.c=863=static int vt_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn,\n--\narch/x86/kvm/vmx/main.c-865-{\narch/x86/kvm/vmx/main.c:866:\tif (is_td(kvm))\narch/x86/kvm/vmx/main.c-867-\t\treturn tdx_gmem_max_mapping_level(kvm, pfn, is_private);\n"
} |
| 15/2 | 2026/08/10 12:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 25938 output: 42 thoughts: 34 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Analyzing the KVM Codebase: `is_td` Function** Okay, let's dive into the KVM x86 code. Specifically, I need to get a handle on `is_td(struct kvm *kvm)`. I'm going to find this function definition, which I believe is declared in `arch/x86/kvm/vmx/common.h`. I'm curious about how the function determines something, probably related to the state of the system that helps with managing the virtualization environment. |
| 16/2 | 2026/08/10 12:53 | tool | read-file |
0mArgs:{
"File": "arch/x86/kvm/vmx/common.h",
"FirstLine": 60,
"LineCount": 15
}Results: {
"Contents": " 60:\t\n 61:\tstatic __always_inline bool is_td(struct kvm *kvm)\n 62:\t{\n 63:\t\treturn kvm-\u003earch.vm_type == KVM_X86_TDX_VM;\n 64:\t}\n 65:\t\n 66:\tstatic __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu)\n 67:\t{\n 68:\t\treturn is_td(vcpu-\u003ekvm);\n 69:\t}\n 70:\t\n 71:\t#else\n 72:\t\n 73:\tstatic __always_inline bool is_td(struct kvm *kvm) { return false; }\n 74:\tstatic __always_inline bool is_td_vcpu(struct kvm_vcpu *vcpu) { return false; }\n"
} |
| 17/2 | 2026/08/10 12:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 26378 output: 25 thoughts: 92 Thoughts: **Investigating TDX VM Creation with Syzkaller** Okay, so the `is_td` function hinges on whether the `kvm->arch.vm_type` is equal to `KVM_X86_TDX_VM`. My initial question here is, can Syzkaller, in its fuzzing efforts, actually create a VM with this specific `KVM_X86_TDX_VM` type? If so, that opens up a whole avenue for potential fuzzing targets. Therefore, the next logical step is to pinpoint the exact definition of `KVM_X86_TDX_VM`. I need to understand how this type is declared, because that might reveal any associated limitations. More critically, I need to trace this type back to `kvm_dev_ioctl_create_vm`. Does the kernel's VM creation code explicitly allow VMs of this type to be constructed? Any restrictions here would impact Syzkaller's ability to even get a TDX VM running, thus constraining any subsequent fuzzing potential. If it *is* allowed, I'll move on. If not, I'm at a roadblock. |
| 18/2 | 2026/08/10 12:53 | tool | grepper |
0mArgs:{
"Expression": "KVM_X86_TDX_VM"
}Results: {
"Output": "Documentation/virt/kvm/api.rst=9418=means the VM type with value @n is supported. Possible values of @n are::\n--\nDocumentation/virt/kvm/api.rst-9424- #define KVM_X86_SNP_VM\t4\nDocumentation/virt/kvm/api.rst:9425: #define KVM_X86_TDX_VM\t5\nDocumentation/virt/kvm/api.rst-9426-\n--\nDocumentation/virt/kvm/x86/intel-tdx.rst=233=control flow is as follows:\n--\nDocumentation/virt/kvm/x86/intel-tdx.rst-236-\nDocumentation/virt/kvm/x86/intel-tdx.rst:237: * KVM_CAP_VM_TYPES: Check if VM type is supported and if KVM_X86_TDX_VM\nDocumentation/virt/kvm/x86/intel-tdx.rst-238- 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/mmu.c=5929=static inline int kvm_mmu_get_tdp_level(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/mmu/mmu.c-5932-\narch/x86/kvm/mmu/mmu.c:5933:\tif (vcpu-\u003ekvm-\u003earch.vm_type == KVM_X86_TDX_VM)\narch/x86/kvm/mmu/mmu.c-5934-\t\tmaxpa = cpuid_query_maxguestphyaddr(vcpu);\n--\narch/x86/kvm/mmu/page_track.c=169=static int kvm_enable_external_write_tracking(struct kvm *kvm)\n--\narch/x86/kvm/mmu/page_track.c-174-\narch/x86/kvm/mmu/page_track.c:175:\tif (kvm-\u003earch.vm_type == KVM_X86_TDX_VM)\narch/x86/kvm/mmu/page_track.c-176-\t\treturn -EOPNOTSUPP;\n--\narch/x86/kvm/vmx/common.h=61=static __always_inline bool is_td(struct kvm *kvm)\narch/x86/kvm/vmx/common.h-62-{\narch/x86/kvm/vmx/common.h:63:\treturn kvm-\u003earch.vm_type == KVM_X86_TDX_VM;\narch/x86/kvm/vmx/common.h-64-}\n--\narch/x86/kvm/vmx/main.c=1058=static int __init vt_init(void)\n--\narch/x86/kvm/vmx/main.c-1078-\t\t\t\t__alignof__(struct vcpu_tdx));\narch/x86/kvm/vmx/main.c:1079:\t\tkvm_caps.supported_vm_types |= BIT(KVM_X86_TDX_VM);\narch/x86/kvm/vmx/main.c-1080-\t}\n--\ntools/arch/x86/include/uapi/asm/kvm.h=925=struct kvm_hyperv_eventfd {\n--\ntools/arch/x86/include/uapi/asm/kvm.h-972-#define KVM_X86_SNP_VM\t\t4\ntools/arch/x86/include/uapi/asm/kvm.h:973:#define KVM_X86_TDX_VM\t\t5\ntools/arch/x86/include/uapi/asm/kvm.h-974-\n"
} |
| 19/2 | 2026/08/10 12:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 27982 output: 44 thoughts: 62 Thoughts: Here's my take on those thoughts, focusing on the implications within my area of expertise: **Diving into the KVM/TDX Integration** Alright, let's dissect this specific line of code: `arch/x86/kvm/vmx/main.c:1079`. It's pretty clear what's happening at a high level. We're setting a bit within `kvm_caps.supported_vm_types`. The bit being set corresponds to `KVM_X86_TDX_VM`. So, essentially, we're signaling that the KVM implementation on x86 now supports running a TDX (Trust Domain Extensions) virtual machine. I'd immediately think about the architectural ramifications here. TDX is a significant security enhancement. It provides isolated virtual machines, protecting the VM's memory and state even from a compromised hypervisor. Setting this bit means the KVM code has been extended to understand and handle the unique characteristics and requirements of TDX VMs. It would suggest that the necessary hardware support for TDX is detected and enabled, or at least that there's a conditional path to enable TDX support. I'd want to know what checks are in place to ensure hardware compatibility; this seems like it might be a configuration option as well. This line is just the tip of the iceberg, of course. I'd be digging into the surrounding code to see what other modifications were made to KVM to accommodate TDX. Specifically, I'd want to check how the VM entry and exit paths are altered to handle the TDX's protected memory regions, the handling of TDX-specific instructions and control registers, and any changes in the memory management scheme. I'd also be very interested in any new or modified security-related code. This is a key step towards enabling TDX in KVM. It's the declaration of intent, the foundation upon which more complex integration is built. It’s an exciting development from a security perspective. |
| 20/2 | 2026/08/10 12:53 | tool | read-file |
0mArgs:{
"File": "arch/x86/kvm/vmx/main.c",
"FirstLine": 1058,
"LineCount": 30
}Results: {
"Contents": "1058:\tstatic int __init vt_init(void)\n1059:\t{\n1060:\t\tunsigned vcpu_size, vcpu_align;\n1061:\t\tint r;\n1062:\t\n1063:\t\tr = vmx_init();\n1064:\t\tif (r)\n1065:\t\t\treturn r;\n1066:\t\n1067:\t\t/*\n1068:\t\t * TDX and VMX have different vCPU structures. Calculate the\n1069:\t\t * maximum size/align so that kvm_init() can use the larger\n1070:\t\t * values to create the kmem_vcpu_cache.\n1071:\t\t */\n1072:\t\tvcpu_size = sizeof(struct vcpu_vmx);\n1073:\t\tvcpu_align = __alignof__(struct vcpu_vmx);\n1074:\t\tif (enable_tdx) {\n1075:\t\t\tvcpu_size = max_t(unsigned, vcpu_size,\n1076:\t\t\t\t\tsizeof(struct vcpu_tdx));\n1077:\t\t\tvcpu_align = max_t(unsigned, vcpu_align,\n1078:\t\t\t\t\t__alignof__(struct vcpu_tdx));\n1079:\t\t\tkvm_caps.supported_vm_types |= BIT(KVM_X86_TDX_VM);\n1080:\t\t}\n1081:\t\n1082:\t\t/*\n1083:\t\t * Common KVM initialization _must_ come last, after this, /dev/kvm is\n1084:\t\t * exposed to userspace!\n1085:\t\t */\n1086:\t\tr = kvm_init(vcpu_size, vcpu_align, THIS_MODULE);\n1087:\t\tif (r)\n"
} |
| 21/2 | 2026/08/10 12:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 28990 output: 18 thoughts: 47 Thoughts: Okay, here's my take on those thoughts, as if they were my own: **Investigating KVM_X86_TDX_VM Support** Alright, so the code says that `KVM_X86_TDX_VM` is only enabled if `enable_tdx` is true. Makes perfect sense, of course, but now I need to figure out the whole picture. I need to understand the control flow here. My next step is clear: I need to trace back and find the definition of that `enable_tdx` variable. Where is it defined? Is it a compile-time option, a module parameter, or something set dynamically at runtime? And crucially, *how* is its value actually determined? I need to understand the conditions that lead to `enable_tdx` being set to true or false. Knowing that will give me the key insights that I need. |
| 22/2 | 2026/08/10 12:54 | tool | grepper |
0mArgs:{
"Expression": "enable_tdx"
}Results: {
"Output": "arch/x86/kvm/vmx/main.c=16=static void vt_disable_virtualization_cpu(void)\n--\narch/x86/kvm/vmx/main.c-18-\t/* Note, TDX *and* VMX need to be disabled if TDX is enabled. */\narch/x86/kvm/vmx/main.c:19:\tif (enable_tdx)\narch/x86/kvm/vmx/main.c-20-\t\ttdx_disable_virtualization_cpu();\n--\narch/x86/kvm/vmx/main.c=24=static __init int vt_hardware_setup(void)\n--\narch/x86/kvm/vmx/main.c-31-\narch/x86/kvm/vmx/main.c:32:\treturn enable_tdx ? tdx_hardware_setup() : 0;\narch/x86/kvm/vmx/main.c-33-}\n--\narch/x86/kvm/vmx/main.c=35=static void vt_hardware_unsetup(void)\narch/x86/kvm/vmx/main.c-36-{\narch/x86/kvm/vmx/main.c:37:\tif (enable_tdx)\narch/x86/kvm/vmx/main.c-38-\t\ttdx_hardware_unsetup();\n--\narch/x86/kvm/vmx/main.c=1058=static int __init vt_init(void)\n--\narch/x86/kvm/vmx/main.c-1073-\tvcpu_align = __alignof__(struct vcpu_vmx);\narch/x86/kvm/vmx/main.c:1074:\tif (enable_tdx) {\narch/x86/kvm/vmx/main.c-1075-\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=3473=int __init tdx_hardware_setup(void)\n--\narch/x86/kvm/vmx/tdx.c-3480-\narch/x86/kvm/vmx/tdx.c:3481:\tif (!enable_tdx)\narch/x86/kvm/vmx/tdx.c-3482-\t\treturn 0;\n--\narch/x86/kvm/vmx/tdx.c-3536-success_disable_tdx:\narch/x86/kvm/vmx/tdx.c:3537:\tenable_tdx = 0;\narch/x86/kvm/vmx/tdx.c-3538-\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"
} |
| 23/2 | 2026/08/10 12:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 30328 output: 45 thoughts: 85 Thoughts: Okay, let's break this down. **Analyzing the TDX Module and Hardware Setup** Alright, so `enable_tdx` is being treated as a module parameter. That's a good starting point – it gives the user control over whether TDX is even attempted. Now, looking at `tdx_hardware_setup`, it seems like there's an early exit condition: `if (!enable_tdx) return 0;`. Hmm, so if the module parameter is set to disable TDX, the entire hardware setup function is skipped, returning zero. That makes perfect sense; it's a clean way to bail out if the user doesn't want it. Digging further down, I see this `success_disable_tdx:` label, and then `enable_tdx = 0;` followed by `return 0;`. This suggests a successful path *through* the hardware setup, where the function might initially try to enable TDX, but then disables it at the end. I'm guessing this might be a cleanup or fallback mechanism. Perhaps it attempts to enable TDX and then disables it if there are issues, or perhaps it's a reset after a successful TDX configuration. Interesting. I need to understand the logic flow here better. I need to see exactly under what circumstances it gets to that line. |
| 24/2 | 2026/08/10 12:54 | tool | read-file |
0mArgs:{
"File": "arch/x86/kvm/vmx/tdx.c",
"FirstLine": 3473,
"LineCount": 50
}Results: {
"Contents": "3473:\tint __init tdx_hardware_setup(void)\n3474:\t{\n3475:\t\tint r, i;\n3476:\t\n3477:\t\t/* tdx_disable_virtualization_cpu() uses associated_tdvcpus. */\n3478:\t\tfor_each_possible_cpu(i)\n3479:\t\t\tINIT_LIST_HEAD(\u0026per_cpu(associated_tdvcpus, i));\n3480:\t\n3481:\t\tif (!enable_tdx)\n3482:\t\t\treturn 0;\n3483:\t\n3484:\t\tif (!enable_ept) {\n3485:\t\t\tpr_err(\"EPT is required for TDX\\n\");\n3486:\t\t\tgoto success_disable_tdx;\n3487:\t\t}\n3488:\t\n3489:\t\tif (!tdp_mmu_enabled || !enable_mmio_caching || !enable_ept_ad_bits) {\n3490:\t\t\tpr_err(\"TDP MMU and MMIO caching and EPT A/D bit is required for TDX\\n\");\n3491:\t\t\tgoto success_disable_tdx;\n3492:\t\t}\n3493:\t\n3494:\t\tif (!enable_apicv) {\n3495:\t\t\tpr_err(\"APICv is required for TDX\\n\");\n3496:\t\t\tgoto success_disable_tdx;\n3497:\t\t}\n3498:\t\n3499:\t\tif (!cpu_feature_enabled(X86_FEATURE_OSXSAVE)) {\n3500:\t\t\tpr_err(\"tdx: OSXSAVE is required for TDX\\n\");\n3501:\t\t\tgoto success_disable_tdx;\n3502:\t\t}\n3503:\t\n3504:\t\tif (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)) {\n3505:\t\t\tpr_err(\"TDX not supported by the host platform\\n\");\n3506:\t\t\tgoto success_disable_tdx;\n3507:\t\t}\n3508:\t\n3509:\t\tr = __tdx_hardware_setup();\n3510:\t\tif (r) {\n3511:\t\t\t/*\n3512:\t\t\t * Disable TDX only but don't fail to load module if the TDX\n3513:\t\t\t * module could not be loaded. No need to print message saying\n3514:\t\t\t * \"module is not loaded\" because it was printed when the first\n3515:\t\t\t * SEAMCALL failed. Don't bother unwinding the S-EPT hooks or\n3516:\t\t\t * vm_size, as kvm_x86_ops have already been finalized (and are\n3517:\t\t\t * intentionally not exported). The S-EPT code is unreachable,\n3518:\t\t\t * and allocating a few more bytes per VM in a should-be-rare\n3519:\t\t\t * failure scenario is a non-issue.\n3520:\t\t\t */\n3521:\t\t\tif (r == -ENODEV)\n3522:\t\t\t\tgoto success_disable_tdx;\n"
} |
| 25/2 | 2026/08/10 12:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 31559 output: 92 thoughts: 2886 Thoughts: **Patch Analysis: Unreachable Code Paths in Standard Fuzzing Environments** Okay, so the code checks for `X86_FEATURE_TDX_HOST_PLATFORM`. If that's not there, `enable_tdx` is set to 0. That means the `KVM_X86_TDX_VM` feature won't be advertised, so syzkaller can't even *create* a TDX VM. Thus, any code paths related to TDX are totally inaccessible in a virtualized environment like GCE or QEMU, which is the standard setup for fuzzing. Right, that makes sense. Can QEMU fake it? No, that won't work. TDX needs the TDX module, which is a signed binary from Intel that runs in a special CPU mode (SEAM VMX root). QEMU doesn't emulate that, nor does it emulate the hardware encryption engines (MKTME) TDX relies on. So, no dice. This TDX stuff is definitely not something that's fuzzeable in a standard environment. But what about those changes in `arch/x86/kvm/vmx/vmx.c` and `arch/x86/kvm/vmx/common.h`? Let's see... `__vmx_handle_notify` is extracted and used. It looks like a straight refactoring; the logic seems identical. And also `handle_bus_lock_vmexit` is changed from `static` to `global`. Okay, so just refactoring. Nothing functional. So, the *only* functional changes are in `tdx.c` and those are unreachable without the TDX hardware. Let's double check. Ah, `tdx_to_vmx_exit_reason` is only called in `tdx_vcpu_enter_exit` and `tdx_failed_vmentry`, all inside `tdx.c`. Got it, completely unreachable. Wait, let's review the instructions. "Return WorthFuzzing=false if the patch only contains code that is unreachable in standard QEMU..." Okay, TDX requires hardware, not emulated by QEMU, and the rest is just refactoring. This patch is a no-go for standard fuzzing. Okay, is `__vmx_handle_notify` inlined, could that change anything in `vmx.c`? It *could*, but it's not a functional change, just the same logic moved around. Let's verify. Let me look at the code: Original `handle_notify`, and the new one. The logic is the same: the `vmcs_set_bits` is unchanged. Wait, the order of operations changed slightly in the new code, `++vcpu->stat.notify_window_exits;` is now called *after* `vmcs_set_bits`. Does this matter? No, `++vcpu->stat.notify_window_exits;` is just a stat counter, and `vmcs_set_bits` does *not* depend on that or the context invalid flag. So the functional impact is zero. The rest of the patch is just `tdx.c` which, again, is unreachable without the physical hardware support. Let's do one last check. Is there any way to reach `tdx_handle_exit` indirectly? `vt_handle_exit` calls it if `is_td_vcpu(vcpu)`. `is_td_vcpu` checks if `is_td(vcpu->kvm)`. `is_td` checks `kvm->arch.vm_type == KVM_X86_TDX_VM`. And that requires `enable_tdx`, which requires the hardware. Got it. Impossible to reach. Okay, the changes are completely unreachable in a standard fuzzing setup. I'm going with `WorthFuzzing=false`. The reasoning is solid: TDX requires physical hardware not emulated in QEMU/GCE, and the rest is just refactoring of existing VMX code, with no change to the generated code. Let's just quickly review the rest of the changes. The changes of `tdx_to_vmx_exit_reason` are also TDX specific. This looks good. Everything is TDX specific except the refactoring. I'm confident. `WorthFuzzing=false`. |
| 26/2 | 2026/08/10 12:54 | tool | set-results |
0mArgs:{
"EnableConfigs": [],
"FocusSymbols": [],
"Reasoning": "The patch modifies KVM TDX (Trust Domain Extensions) code, which requires specific physical hardware support (Intel TDX) not emulated in standard QEMU/GCE environments. The changes to standard VMX code are purely refactoring to share logic with TDX, with no functional impact.",
"WorthFuzzing": false
}Results: {
"EnableConfigs": null,
"FocusSymbols": [],
"Reasoning": "The patch modifies KVM TDX (Trust Domain Extensions) code, which requires specific physical hardware support (Intel TDX) not emulated in standard QEMU/GCE environments. The changes to standard VMX code are purely refactoring to share logic with TDX, with no functional impact.",
"WorthFuzzing": false
} |
| 27/1 | 2026/08/10 12:54 | action | If |
0mArgs:{
"WorthFuzzing": false
}Results: null |
| Total Calls | Total Tokens | Avg Tokens | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|
| Total Calls | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|