AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/08/02 02:58	flow	patch-triage	1m Args: null Results: { "EnableConfigs": [ "KVM_SMM", "KVM_AMD_SEV", "KVM_INTEL_TDX", "INTEL_TDX_HOST", "CRYPTO_DEV_SP_PSP", "CRYPTO_DEV_CCP_DD", "KVM_INTEL", "KVM_AMD", "AMD_IOMMU", "CMA", "X86_X2APIC", "X86_MCE" ], "FocusSymbols": [ "emulator_leave_smm" ], "Reasoning": "The patch fixes a bug where KVM does not properly handle invalid guest state when leaving System Management Mode (SMM) via the RSM instruction. It modifies `emulator_leave_smm` to check if unhandleable emulation is required, and if so, returns `X86EMUL_UNHANDLEABLE`. The rest of the patch refactors the `vcpu_pre_run` op into `vcpu_needs_initialization` and `unhandleable_emulation_required` to support this check. We should focus fuzzing on `emulator_leave_smm` to test this new logic.", "WorthFuzzing": true }
1/1	2026/08/02 02:58	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 2ab87a83786d335a6b27d5dd25b8f521ecd4bc74\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Sun Aug 2 02:58:06 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h\nindex 5cb132eca3c35..e213c9ae3e301 100644\n--- a/arch/x86/include/asm/kvm-x86-ops.h\n+++ b/arch/x86/include/asm/kvm-x86-ops.h\n@@ -63,11 +63,12 @@ KVM_X86_OP_OPTIONAL(flush_remote_tlbs_range)\n #endif\n KVM_X86_OP(flush_tlb_gva)\n KVM_X86_OP(flush_tlb_guest)\n-KVM_X86_OP(vcpu_pre_run)\n+KVM_X86_OP_OPTIONAL_RET0(vcpu_needs_initialization)\n KVM_X86_OP(vcpu_run)\n KVM_X86_OP(handle_exit)\n KVM_X86_OP(skip_emulated_instruction)\n KVM_X86_OP_OPTIONAL(update_emulated_instruction)\n+KVM_X86_OP_OPTIONAL_RET0(unhandleable_emulation_required)\n KVM_X86_OP(set_interrupt_shadow)\n KVM_X86_OP(get_interrupt_shadow)\n KVM_X86_OP(patch_hypercall)\ndiff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h\nindex 7a258831616fa..283847619ff88 100644\n--- a/arch/x86/include/asm/kvm_host.h\n+++ b/arch/x86/include/asm/kvm_host.h\n@@ -1586,13 +1586,15 @@ struct kvm_x86_ops {\n \t /\n \tvoid (flush_tlb_guest)(struct kvm_vcpu vcpu);\n \n-\tint (vcpu_pre_run)(struct kvm_vcpu vcpu);\n+\tbool (vcpu_needs_initialization)(struct kvm_vcpu vcpu);\n \tenum exit_fastpath_completion (vcpu_run)(struct kvm_vcpu vcpu,\n \t\t\t\t\t\t u64 run_flags);\n \tint (handle_exit)(struct kvm_vcpu vcpu,\n \t\tenum exit_fastpath_completion exit_fastpath);\n \tint (skip_emulated_instruction)(struct kvm_vcpu vcpu);\n \tvoid (update_emulated_instruction)(struct kvm_vcpu vcpu);\n+\tbool (unhandleable_emulation_required)(struct kvm_vcpu vcpu);\n+\n \tvoid (set_interrupt_shadow)(struct kvm_vcpu vcpu, int mask);\n \tu32 (get_interrupt_shadow)(struct kvm_vcpu vcpu);\n \tvoid (patch_hypercall)(struct kvm_vcpu vcpu,\ndiff --git a/arch/x86/kvm/smm.c b/arch/x86/kvm/smm.c\nindex a446487bdd5cf..656a38dad7e7a 100644\n--- a/arch/x86/kvm/smm.c\n+++ b/arch/x86/kvm/smm.c\n@@ -649,6 +649,10 @@ int emulator_leave_smm(struct x86_emulate_ctxt ctxt)\n #endif\n \t\tret = rsm_load_state_32(ctxt, \u0026smram.smram32);\n \n+\tif (ret == X86EMUL_CONTINUE \u0026\u0026\n+\t kvm_x86_call(unhandleable_emulation_required)(vcpu))\n+\t\tret = X86EMUL_UNHANDLEABLE;\n+\n \t/\n \t If RSM fails and triggers shutdown, architecturally the shutdown\n \t * occurs before the transition to guest mode. But due to KVM's\ndiff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c\nindex 90a08d36d843d..fcb41dfde4c02 100644\n--- a/arch/x86/kvm/svm/sev.c\n+++ b/arch/x86/kvm/svm/sev.c\n@@ -3556,6 +3556,11 @@ void sev_free_vcpu(struct kvm_vcpu vcpu)\n \t__sev_es_unmap_ghcb(svm);\n }\n \n+bool sev_vcpu_needs_initialization(struct kvm_vcpu vcpu)\n+{\n+\treturn to_kvm_sev_info(vcpu-\u003ekvm)-\u003eneed_init;\n+}\n+\n int pre_sev_run(struct vcpu_svm svm, int cpu)\n {\n \tstruct svm_cpu_data sd = per_cpu_ptr(\u0026svm_data, cpu);\ndiff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c\nindex c1e6d62512b95..9d607b98bd067 100644\n--- a/arch/x86/kvm/svm/svm.c\n+++ b/arch/x86/kvm/svm/svm.c\n@@ -4400,16 +4400,6 @@ static void svm_cancel_injection(struct kvm_vcpu vcpu)\n \tsvm_complete_interrupts(vcpu);\n }\n \n-static int svm_vcpu_pre_run(struct kvm_vcpu vcpu)\n-{\n-#ifdef CONFIG_KVM_AMD_SEV\n-\tif (to_kvm_sev_info(vcpu-\u003ekvm)-\u003eneed_init)\n-\t\treturn -EINVAL;\n-#endif\n-\n-\treturn 1;\n-}\n-\n static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu vcpu)\n {\n \tstruct vcpu_svm svm = to_svm(vcpu);\n@@ -5376,7 +5366,6 @@ struct kvm_x86_ops svm_x86_ops __initdata = {\n \t.flush_tlb_gva = svm_flush_tlb_gva,\n \t.flush_tlb_guest = svm_flush_tlb_guest,\n \n-\t.vcpu_pre_run = svm_vcpu_pre_run,\n \t.vcpu_run = svm_vcpu_run,\n \t.handle_exit = svm_handle_exit,\n \t.skip_emulated_instruction = svm_skip_emulated_instruction,\n@@ -5434,6 +5423,7 @@ struct kvm_x86_ops svm_x86_ops __initdata = {\n #endif\n \n #ifdef CONFIG_KVM_AMD_SEV\n+\t.vcpu_needs_initialization = sev_vcpu_needs_initialization,\n \t.dev_get_attr = sev_dev_get_attr,\n \t.mem_enc_ioctl = sev_mem_enc_ioctl,\n \t.mem_enc_register_region = sev_mem_enc_register_region,\ndiff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h\nindex a327bf751ecd5..66b44b54608e8 100644\n--- a/arch/x86/kvm/svm/svm.h\n+++ b/arch/x86/kvm/svm/svm.h\n@@ -979,6 +979,7 @@ void sev_es_prepare_switch_to_guest(struct vcpu_svm svm, struct sev_es_save_are\n void sev_es_unmap_ghcb(struct vcpu_svm svm);\n \n #ifdef CONFIG_KVM_AMD_SEV\n+bool sev_vcpu_needs_initialization(struct kvm_vcpu vcpu);\n int sev_mem_enc_ioctl(struct kvm kvm, void __user argp);\n int sev_mem_enc_register_region(struct kvm kvm,\n \t\t\t\tstruct kvm_enc_region range);\ndiff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c\nindex 04f986e3d439a..0ff3230fd95e8 100644\n--- a/arch/x86/kvm/vmx/main.c\n+++ b/arch/x86/kvm/vmx/main.c\n@@ -140,12 +140,10 @@ static void vt_vcpu_put(struct kvm_vcpu vcpu)\n \tvmx_vcpu_put(vcpu);\n }\n \n-static int vt_vcpu_pre_run(struct kvm_vcpu vcpu)\n+static bool vt_vcpu_needs_initialization(struct kvm_vcpu vcpu)\n {\n-\tif (is_td_vcpu(vcpu))\n-\t\treturn tdx_vcpu_pre_run(vcpu);\n-\n-\treturn vmx_vcpu_pre_run(vcpu);\n+\treturn is_td_vcpu(vcpu) \u0026\u0026\n+\t tdx_vcpu_needs_initialization(vcpu);\n }\n \n static fastpath_t vt_vcpu_run(struct kvm_vcpu vcpu, u64 run_flags)\n@@ -165,6 +163,16 @@ static int vt_handle_exit(struct kvm_vcpu vcpu,\n \treturn vmx_handle_exit(vcpu, fastpath);\n }\n \n+static bool vt_unhandleable_emulation_required(struct kvm_vcpu vcpu)\n+{\n+\tif (is_td_vcpu(vcpu)) {\n+\t\tWARN_ON_ONCE(to_vt(vcpu)-\u003eemulation_required);\n+\t\treturn false;\n+\t}\n+\n+\treturn vmx_unhandleable_emulation_required(vcpu);\n+}\n+\n static int vt_set_msr(struct kvm_vcpu vcpu, struct msr_data msr_info)\n {\n \tif (unlikely(is_td_vcpu(vcpu)))\n@@ -939,11 +947,12 @@ struct kvm_x86_ops vt_x86_ops __initdata = {\n \t.flush_tlb_gva = vt_op(flush_tlb_gva),\n \t.flush_tlb_guest = vt_op(flush_tlb_guest),\n \n-\t.vcpu_pre_run = vt_op(vcpu_pre_run),\n+\t.vcpu_needs_initialization = vt_op_tdx_only(vcpu_needs_initialization),\n \t.vcpu_run = vt_op(vcpu_run),\n \t.handle_exit = vt_op(handle_exit),\n \t.skip_emulated_instruction = vmx_skip_emulated_instruction,\n \t.update_emulated_instruction = vmx_update_emulated_instruction,\n+\t.unhandleable_emulation_required = vt_op(unhandleable_emulation_required),\n \t.set_interrupt_shadow = vt_op(set_interrupt_shadow),\n \t.get_interrupt_shadow = vt_op(get_interrupt_shadow),\n \t.patch_hypercall = vt_op(patch_hypercall),\ndiff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c\nindex d1af0a752e97e..b272c20586a74 100644\n--- a/arch/x86/kvm/vmx/tdx.c\n+++ b/arch/x86/kvm/vmx/tdx.c\n@@ -897,13 +897,10 @@ void tdx_vcpu_free(struct kvm_vcpu vcpu)\n \ttdx-\u003estate = VCPU_TD_STATE_UNINITIALIZED;\n }\n \n-int tdx_vcpu_pre_run(struct kvm_vcpu vcpu)\n+bool tdx_vcpu_needs_initialization(struct kvm_vcpu vcpu)\n {\n-\tif (unlikely(to_tdx(vcpu)-\u003estate != VCPU_TD_STATE_INITIALIZED \|\|\n-\t\t to_kvm_tdx(vcpu-\u003ekvm)-\u003estate != TD_STATE_RUNNABLE))\n-\t\treturn -EINVAL;\n-\n-\treturn 1;\n+\treturn to_tdx(vcpu)-\u003estate != VCPU_TD_STATE_INITIALIZED \|\|\n+\t to_kvm_tdx(vcpu-\u003ekvm)-\u003estate != TD_STATE_RUNNABLE;\n }\n \n static __always_inline u32 tdcall_to_vmx_exit_reason(struct kvm_vcpu vcpu)\ndiff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c\nindex e4b9ac7fed9f0..76160adf82970 100644\n--- a/arch/x86/kvm/vmx/vmx.c\n+++ b/arch/x86/kvm/vmx/vmx.c\n@@ -6035,7 +6035,7 @@ static int handle_nmi_window(struct kvm_vcpu vcpu)\n * with unsrestricted guest mode disabled) and KVM can't faithfully emulate the\n * current vCPU state.\n /\n-static bool vmx_unhandleable_emulation_required(struct kvm_vcpu vcpu)\n+bool vmx_unhandleable_emulation_required(struct kvm_vcpu vcpu)\n {\n \tstruct vcpu_vmx vmx = to_vmx(vcpu);\n \n@@ -6110,16 +6110,6 @@ static int handle_invalid_guest_state(struct kvm_vcpu vcpu)\n \treturn 1;\n }\n \n-int vmx_vcpu_pre_run(struct kvm_vcpu vcpu)\n-{\n-\tif (vmx_unhandleable_emulation_required(vcpu)) {\n-\t\tkvm_prepare_emulation_failure_exit(vcpu);\n-\t\treturn 0;\n-\t}\n-\n-\treturn 1;\n-}\n-\n /\n Indicate a busy-waiting vcpu in spinlock. We do not enable the PAUSE\n * exiting, so only get here on cpu with PAUSE-Loop-Exiting.\ndiff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h\nindex 4098580742462..cdb38d940cfb7 100644\n--- a/arch/x86/kvm/vmx/x86_ops.h\n+++ b/arch/x86/kvm/vmx/x86_ops.h\n@@ -21,7 +21,6 @@ int vmx_vm_init(struct kvm kvm);\n void vmx_vm_destroy(struct kvm kvm);\n int vmx_vcpu_precreate(struct kvm kvm);\n int vmx_vcpu_create(struct kvm_vcpu vcpu);\n-int vmx_vcpu_pre_run(struct kvm_vcpu vcpu);\n fastpath_t vmx_vcpu_run(struct kvm_vcpu vcpu, u64 run_flags);\n void vmx_vcpu_free(struct kvm_vcpu vcpu);\n void vmx_vcpu_reset(struct kvm_vcpu vcpu, bool init_event);\n@@ -31,6 +30,7 @@ int vmx_handle_exit(struct kvm_vcpu vcpu, fastpath_t exit_fastpath);\n void vmx_handle_exit_irqoff(struct kvm_vcpu vcpu);\n int vmx_skip_emulated_instruction(struct kvm_vcpu vcpu);\n void vmx_update_emulated_instruction(struct kvm_vcpu vcpu);\n+bool vmx_unhandleable_emulation_required(struct kvm_vcpu vcpu);\n int vmx_set_msr(struct kvm_vcpu vcpu, struct msr_data msr_info);\n #ifdef CONFIG_KVM_SMM\n int vmx_smi_allowed(struct kvm_vcpu vcpu, bool for_injection);\n@@ -137,7 +137,7 @@ int tdx_vcpu_create(struct kvm_vcpu vcpu);\n void tdx_vcpu_reset(struct kvm_vcpu vcpu, bool init_event);\n void tdx_vcpu_free(struct kvm_vcpu vcpu);\n void tdx_vcpu_load(struct kvm_vcpu vcpu, int cpu);\n-int tdx_vcpu_pre_run(struct kvm_vcpu vcpu);\n+bool tdx_vcpu_needs_initialization(struct kvm_vcpu vcpu);\n fastpath_t tdx_vcpu_run(struct kvm_vcpu vcpu, u64 run_flags);\n void tdx_prepare_switch_to_guest(struct kvm_vcpu vcpu);\n void tdx_vcpu_put(struct kvm_vcpu vcpu);\ndiff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c\nindex 0f1a829032c06..d94b59140c452 100644\n--- a/arch/x86/kvm/x86.c\n+++ b/arch/x86/kvm/x86.c\n@@ -8867,7 +8867,15 @@ static int kvm_x86_vcpu_pre_run(struct kvm_vcpu vcpu)\n \t !kvm_apic_init_sipi_allowed(vcpu))\n \t\treturn -EINVAL;\n \n-\treturn kvm_x86_call(vcpu_pre_run)(vcpu);\n+\tif (kvm_x86_call(vcpu_needs_initialization)(vcpu))\n+\t\treturn -EINVAL;\n+\n+\tif (kvm_x86_call(unhandleable_emulation_required)(vcpu)) {\n+\t\tkvm_prepare_emulation_failure_exit(vcpu);\n+\t\treturn 0;\n+\t}\n+\n+\treturn 1;\n }\n \n int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu vcpu)\ndiff --git a/tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c b/tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c\nindex 578283893ab37..c8379124b3172 100644\n--- a/tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c\n+++ b/tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c\n@@ -2,6 +2,7 @@\n #include \"test_util.h\"\n #include \"kvm_util.h\"\n #include \"processor.h\"\n+#include \"smm.h\"\n #include \"vmx.h\"\n \n #include \u003cstring.h\u003e\n@@ -9,9 +10,23 @@\n \n #include \"kselftest.h\"\n \n-#define ARBITRARY_IO_PORT 0x2000\n+#define ARBITRARY_IO_PORT 0x80\n \n-static struct kvm_vm vm;\n+/\n+ The 64-bit SMRAM state-save area starts at SMBASE + 0xfe00. TR starts at\n+ * offset 0xfe90, and attributes is the second 16-bit field in the descriptor.\n+ /\n+#define SMRAM64_TR_ATTRIBUTES_OFFSET\t0xfe92\n+#define SMRAM_GPA\t\t\t0x1000000\n+\n+/\n+ * SMI handler that runs in 16-bit Real Mode. Syncs with L0 via port I/O, then\n+ * executes RSM to trigger the consumption of invalid guest state.\n+ /\n+static u8 smi_handler[] = {\n+\t0xe4, ARBITRARY_IO_PORT,\t/ IN $ARBITRARY_IO_PORT, %al /\n+\t0x0f, 0xaa,\t\t\t/ RSM /\n+};\n \n static void l2_guest_code(void)\n {\n@@ -19,8 +34,9 @@ static void l2_guest_code(void)\n \t Generate an exit to L0 userspace, i.e. main(), via I/O to an\n \t * arbitrary port.\n \t /\n-\tasm volatile(\"inb %%dx, %%al\"\n-\t\t : : [port] \"d\" (ARBITRARY_IO_PORT) : \"rax\");\n+\tasm volatile(\"inb $\" __stringify(ARBITRARY_IO_PORT) \", %%al\"\n+\t\t ::: \"rax\");\n+\tGUEST_FAIL(\"L2 resumed after stuffing invalid guest state\");\n }\n \n static void l1_guest_code(struct vmx_pages vmx_pages)\n@@ -46,35 +62,50 @@ static void l1_guest_code(struct vmx_pages vmx_pages)\n \tGUEST_DONE();\n }\n \n-int main(int argc, char argv[])\n+static void vcpu_run_to_io(struct kvm_vcpu vcpu, bool want_l2)\n {\n-\tgva_t vmx_pages_gva;\n-\tstruct kvm_sregs sregs;\n-\tstruct kvm_vcpu vcpu;\n-\tstruct kvm_run run;\n-\tstruct ucall uc;\n+\tstruct kvm_run run = vcpu-\u003erun;\n \n-\tTEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));\n+\tvcpu_run(vcpu);\n \n-\tvm = vm_create_with_one_vcpu(\u0026vcpu, l1_guest_code);\n+\tTEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);\n \n-\t/* Allocate VMX pages and shared descriptors (vmx_pages). /\n-\tvcpu_alloc_vmx(vm, \u0026vmx_pages_gva);\n-\tvcpu_args_set(vcpu, 1, vmx_pages_gva);\n+\tTEST_ASSERT(run-\u003eio.port == ARBITRARY_IO_PORT \u0026\u0026\n+\t\t (!!(run-\u003eflags \u0026 KVM_RUN_X86_GUEST_MODE) == want_l2 \|\|\n+\t\t !kvm_has_cap(KVM_CAP_X86_GUEST_MODE)),\n+\t\t \"Expected IN from port 0x%x from L%u, got port 0x%x from L%u\",\n+\t\t ARBITRARY_IO_PORT, 1 + want_l2, run-\u003eio.port,\n+\t\t 1 + !!(run-\u003eflags \u0026 KVM_RUN_X86_GUEST_MODE));\n+}\n \n-\tvcpu_run(vcpu);\n+static struct kvm_vm vm_create_and_run_l2(struct kvm_vcpu *vcpu)\n+{\n+\tgva_t vmx_pages_gva;\n+\tstruct kvm_vm vm;\n+\n+\tvm = vm_create_with_one_vcpu(vcpu, l1_guest_code);\n \n-\trun = vcpu-\u003erun;\n+\t/* Allocate VMX pages and shared descriptors (vmx_pages). /\n+\tvcpu_alloc_vmx(vm, \u0026vmx_pages_gva);\n+\tvcpu_args_set(vcpu, 1, vmx_pages_gva);\n \n \t/\n \t The first exit to L0 userspace should be an I/O access from L2.\n \t * Running L1 should launch L2 without triggering an exit to userspace.\n \t /\n-\tTEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);\n+\tvcpu_run_to_io(vcpu, true);\n \n-\tTEST_ASSERT(run-\u003eio.port == ARBITRARY_IO_PORT,\n-\t\t \"Expected IN from port %d from L2, got port %d\",\n-\t\t ARBITRARY_IO_PORT, run-\u003eio.port);\n+\treturn vm;\n+}\n+\n+static void test_invalid_l2_guest_state(void)\n+{\n+\tstruct kvm_sregs sregs;\n+\tstruct kvm_vcpu vcpu;\n+\tstruct kvm_vm vm;\n+\tstruct ucall uc;\n+\n+\tvm = vm_create_and_run_l2(\u0026vcpu);\n \n \t/\n \t Stuff invalid guest state for L2 by making TR unusable. The next\n@@ -96,4 +127,49 @@ int main(int argc, char argv[])\n \tdefault:\n \t\tTEST_FAIL(\"Unexpected ucall: %lu\", uc.cmd);\n \t}\n+\n+\tkvm_vm_free(vm);\n+}\n+\n+static void test_invalid_l2_guest_state_rsm(void)\n+{\n+\tstruct kvm_vcpu vcpu;\n+\tstruct kvm_vm vm;\n+\tu16 tr_attrs;\n+\n+\tif (!kvm_has_cap(KVM_CAP_X86_SMM))\n+\t\treturn;\n+\n+\tvm = vm_create_and_run_l2(\u0026vcpu);\n+\n+\t/\n+\t Inject SMI while L2 is active, run the vCPU to get I/O exit from L1,\n+\t * then stuff TR in the SMRAM state-save area so that RSM restores\n+\t * invalid L2 state.\n+\t /\n+\tsetup_smram(vm, vcpu, SMRAM_GPA, smi_handler, sizeof(smi_handler));\n+\tinject_smi(vcpu);\n+\n+\tvcpu_run_to_io(vcpu, false);\n+\n+\t/ Clear the present bit in SMRAM to make TR unusable. /\n+\ttr_attrs = addr_gpa2hva(vm, SMRAM_GPA + SMRAM64_TR_ATTRIBUTES_OFFSET);\n+\ttr_attrs \u0026= ~BIT(7);\n+\n+\tvcpu_run(vcpu);\n+\n+\t/\n+\t For RSM, L1 gets the SHUTDOWN because RSM is architecturally defined\n+\t * to result in shutdown if the CPU detects invalid state in SMRAM.\n+\t /\n+\tTEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_SHUTDOWN);\n+\tkvm_vm_free(vm);\n+}\n+\n+int main(int argc, char argv[])\n+{\n+\tTEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));\n+\n+\ttest_invalid_l2_guest_state();\n+\ttest_invalid_l2_guest_state_rsm();\n }\n" }
2/1	2026/08/02 02:58	agent	patch-evaluator	1m Model: best-expensive Args: null Results: { "EnableConfigs": [ "KVM_SMM", "KVM_AMD_SEV", "KVM_INTEL_TDX", "INTEL_TDX_HOST", "CRYPTO_DEV_SP_PSP", "CRYPTO_DEV_CCP_DD", "KVM_INTEL", "KVM_AMD", "AMD_IOMMU", "CMA", "X86_X2APIC", "X86_MCE" ], "FocusSymbols": [ "emulator_leave_smm" ], "Reasoning": "The patch fixes a bug where KVM does not properly handle invalid guest state when leaving System Management Mode (SMM) via the RSM instruction. It modifies `emulator_leave_smm` to check if unhandleable emulation is required, and if so, returns `X86EMUL_UNHANDLEABLE`. The rest of the patch refactors the `vcpu_pre_run` op into `vcpu_needs_initialization` and `unhandleable_emulation_required` to support this check. We should focus fuzzing on `emulator_leave_smm` to test this new logic.", "WorthFuzzing": true } 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 2ab87a83786d335a6b27d5dd25b8f521ecd4bc74 Author: syz-cluster <triage@syzkaller.com> Date: Sun Aug 2 02:58:06 2026 +0000 syz-cluster: applied patch under review diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h index 5cb132eca3c35..e213c9ae3e301 100644 --- a/arch/x86/include/asm/kvm-x86-ops.h +++ b/arch/x86/include/asm/kvm-x86-ops.h @@ -63,11 +63,12 @@ KVM_X86_OP_OPTIONAL(flush_remote_tlbs_range) #endif KVM_X86_OP(flush_tlb_gva) KVM_X86_OP(flush_tlb_guest) -KVM_X86_OP(vcpu_pre_run) +KVM_X86_OP_OPTIONAL_RET0(vcpu_needs_initialization) KVM_X86_OP(vcpu_run) KVM_X86_OP(handle_exit) KVM_X86_OP(skip_emulated_instruction) KVM_X86_OP_OPTIONAL(update_emulated_instruction) +KVM_X86_OP_OPTIONAL_RET0(unhandleable_emulation_required) KVM_X86_OP(set_interrupt_shadow) KVM_X86_OP(get_interrupt_shadow) KVM_X86_OP(patch_hypercall) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 7a258831616fa..283847619ff88 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1586,13 +1586,15 @@ struct kvm_x86_ops { / void (flush_tlb_guest)(struct kvm_vcpu vcpu); - int (vcpu_pre_run)(struct kvm_vcpu vcpu); + bool (vcpu_needs_initialization)(struct kvm_vcpu vcpu); enum exit_fastpath_completion (vcpu_run)(struct kvm_vcpu vcpu, u64 run_flags); int (handle_exit)(struct kvm_vcpu vcpu, enum exit_fastpath_completion exit_fastpath); int (skip_emulated_instruction)(struct kvm_vcpu vcpu); void (update_emulated_instruction)(struct kvm_vcpu vcpu); + bool (unhandleable_emulation_required)(struct kvm_vcpu vcpu); + void (set_interrupt_shadow)(struct kvm_vcpu vcpu, int mask); u32 (get_interrupt_shadow)(struct kvm_vcpu vcpu); void (patch_hypercall)(struct kvm_vcpu vcpu, diff --git a/arch/x86/kvm/smm.c b/arch/x86/kvm/smm.c index a446487bdd5cf..656a38dad7e7a 100644 --- a/arch/x86/kvm/smm.c +++ b/arch/x86/kvm/smm.c @@ -649,6 +649,10 @@ int emulator_leave_smm(struct x86_emulate_ctxt ctxt) #endif ret = rsm_load_state_32(ctxt, &smram.smram32); + if (ret == X86EMUL_CONTINUE && + kvm_x86_call(unhandleable_emulation_required)(vcpu)) + ret = X86EMUL_UNHANDLEABLE; + /* * If RSM fails and triggers shutdown, architecturally the shutdown * occurs before the transition to guest mode. But due to KVM's diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 90a08d36d843d..fcb41dfde4c02 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3556,6 +3556,11 @@ void sev_free_vcpu(struct kvm_vcpu vcpu) __sev_es_unmap_ghcb(svm); } +bool sev_vcpu_needs_initialization(struct kvm_vcpu vcpu) +{ + return to_kvm_sev_info(vcpu->kvm)->need_init; +} + int pre_sev_run(struct vcpu_svm svm, int cpu) { struct svm_cpu_data sd = per_cpu_ptr(&svm_data, cpu); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index c1e6d62512b95..9d607b98bd067 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4400,16 +4400,6 @@ static void svm_cancel_injection(struct kvm_vcpu vcpu) svm_complete_interrupts(vcpu); } -static int svm_vcpu_pre_run(struct kvm_vcpu vcpu) -{ -#ifdef CONFIG_KVM_AMD_SEV - if (to_kvm_sev_info(vcpu->kvm)->need_init) - return -EINVAL; -#endif - - return 1; -} - static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu vcpu) { struct vcpu_svm svm = to_svm(vcpu); @@ -5376,7 +5366,6 @@ struct kvm_x86_ops svm_x86_ops __initdata = { .flush_tlb_gva = svm_flush_tlb_gva, .flush_tlb_guest = svm_flush_tlb_guest, - .vcpu_pre_run = svm_vcpu_pre_run, .vcpu_run = svm_vcpu_run, .handle_exit = svm_handle_exit, .skip_emulated_instruction = svm_skip_emulated_instruction, @@ -5434,6 +5423,7 @@ struct kvm_x86_ops svm_x86_ops __initdata = { #endif #ifdef CONFIG_KVM_AMD_SEV + .vcpu_needs_initialization = sev_vcpu_needs_initialization, .dev_get_attr = sev_dev_get_attr, .mem_enc_ioctl = sev_mem_enc_ioctl, .mem_enc_register_region = sev_mem_enc_register_region, diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index a327bf751ecd5..66b44b54608e8 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -979,6 +979,7 @@ void sev_es_prepare_switch_to_guest(struct vcpu_svm svm, struct sev_es_save_are void sev_es_unmap_ghcb(struct vcpu_svm svm); #ifdef CONFIG_KVM_AMD_SEV +bool sev_vcpu_needs_initialization(struct kvm_vcpu vcpu); int sev_mem_enc_ioctl(struct kvm kvm, void __user argp); int sev_mem_enc_register_region(struct kvm kvm, struct kvm_enc_region range); diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c index 04f986e3d439a..0ff3230fd95e8 100644 --- a/arch/x86/kvm/vmx/main.c +++ b/arch/x86/kvm/vmx/main.c @@ -140,12 +140,10 @@ static void vt_vcpu_put(struct kvm_vcpu vcpu) vmx_vcpu_put(vcpu); } -static int vt_vcpu_pre_run(struct kvm_vcpu vcpu) +static bool vt_vcpu_needs_initialization(struct kvm_vcpu vcpu) { - if (is_td_vcpu(vcpu)) - return tdx_vcpu_pre_run(vcpu); - - return vmx_vcpu_pre_run(vcpu); + return is_td_vcpu(vcpu) && + tdx_vcpu_needs_initialization(vcpu); } static fastpath_t vt_vcpu_run(struct kvm_vcpu vcpu, u64 run_flags) @@ -165,6 +163,16 @@ static int vt_handle_exit(struct kvm_vcpu vcpu, return vmx_handle_exit(vcpu, fastpath); } +static bool vt_unhandleable_emulation_required(struct kvm_vcpu vcpu) +{ + if (is_td_vcpu(vcpu)) { + WARN_ON_ONCE(to_vt(vcpu)->emulation_required); + return false; + } + + return vmx_unhandleable_emulation_required(vcpu); +} + static int vt_set_msr(struct kvm_vcpu vcpu, struct msr_data msr_info) { if (unlikely(is_td_vcpu(vcpu))) @@ -939,11 +947,12 @@ struct kvm_x86_ops vt_x86_ops __initdata = { .flush_tlb_gva = vt_op(flush_tlb_gva), .flush_tlb_guest = vt_op(flush_tlb_guest), - .vcpu_pre_run = vt_op(vcpu_pre_run), + .vcpu_needs_initialization = vt_op_tdx_only(vcpu_needs_initialization), .vcpu_run = vt_op(vcpu_run), .handle_exit = vt_op(handle_exit), .skip_emulated_instruction = vmx_skip_emulated_instruction, .update_emulated_instruction = vmx_update_emulated_instruction, + .unhandleable_emulation_required = vt_op(unhandleable_emulation_required), .set_interrupt_shadow = vt_op(set_interrupt_shadow), .get_interrupt_shadow = vt_op(get_interrupt_shadow), .patch_hypercall = vt_op(patch_hypercall), diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index d1af0a752e97e..b272c20586a74 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -897,13 +897,10 @@ void tdx_vcpu_free(struct kvm_vcpu vcpu) tdx->state = VCPU_TD_STATE_UNINITIALIZED; } -int tdx_vcpu_pre_run(struct kvm_vcpu vcpu) +bool tdx_vcpu_needs_initialization(struct kvm_vcpu vcpu) { - if (unlikely(to_tdx(vcpu)->state != VCPU_TD_STATE_INITIALIZED \|\| - to_kvm_tdx(vcpu->kvm)->state != TD_STATE_RUNNABLE)) - return -EINVAL; - - return 1; + return to_tdx(vcpu)->state != VCPU_TD_STATE_INITIALIZED \|\| + to_kvm_tdx(vcpu->kvm)->state != TD_STATE_RUNNABLE; } static __always_inline u32 tdcall_to_vmx_exit_reason(struct kvm_vcpu vcpu) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index e4b9ac7fed9f0..76160adf82970 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6035,7 +6035,7 @@ static int handle_nmi_window(struct kvm_vcpu vcpu) * with unsrestricted guest mode disabled) and KVM can't faithfully emulate the * current vCPU state. / -static bool vmx_unhandleable_emulation_required(struct kvm_vcpu vcpu) +bool vmx_unhandleable_emulation_required(struct kvm_vcpu vcpu) { struct vcpu_vmx vmx = to_vmx(vcpu); @@ -6110,16 +6110,6 @@ static int handle_invalid_guest_state(struct kvm_vcpu vcpu) return 1; } -int vmx_vcpu_pre_run(struct kvm_vcpu vcpu) -{ - if (vmx_unhandleable_emulation_required(vcpu)) { - kvm_prepare_emulation_failure_exit(vcpu); - return 0; - } - - return 1; -} - /* * Indicate a busy-waiting vcpu in spinlock. We do not enable the PAUSE * exiting, so only get here on cpu with PAUSE-Loop-Exiting. diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h index 4098580742462..cdb38d940cfb7 100644 --- a/arch/x86/kvm/vmx/x86_ops.h +++ b/arch/x86/kvm/vmx/x86_ops.h @@ -21,7 +21,6 @@ int vmx_vm_init(struct kvm kvm); void vmx_vm_destroy(struct kvm kvm); int vmx_vcpu_precreate(struct kvm kvm); int vmx_vcpu_create(struct kvm_vcpu vcpu); -int vmx_vcpu_pre_run(struct kvm_vcpu vcpu); fastpath_t vmx_vcpu_run(struct kvm_vcpu vcpu, u64 run_flags); void vmx_vcpu_free(struct kvm_vcpu vcpu); void vmx_vcpu_reset(struct kvm_vcpu vcpu, bool init_event); @@ -31,6 +30,7 @@ int vmx_handle_exit(struct kvm_vcpu vcpu, fastpath_t exit_fastpath); void vmx_handle_exit_irqoff(struct kvm_vcpu vcpu); int vmx_skip_emulated_instruction(struct kvm_vcpu vcpu); void vmx_update_emulated_instruction(struct kvm_vcpu vcpu); +bool vmx_unhandleable_emulation_required(struct kvm_vcpu vcpu); int vmx_set_msr(struct kvm_vcpu vcpu, struct msr_data msr_info); #ifdef CONFIG_KVM_SMM int vmx_smi_allowed(struct kvm_vcpu vcpu, bool for_injection); @@ -137,7 +137,7 @@ int tdx_vcpu_create(struct kvm_vcpu vcpu); void tdx_vcpu_reset(struct kvm_vcpu vcpu, bool init_event); void tdx_vcpu_free(struct kvm_vcpu vcpu); void tdx_vcpu_load(struct kvm_vcpu vcpu, int cpu); -int tdx_vcpu_pre_run(struct kvm_vcpu vcpu); +bool tdx_vcpu_needs_initialization(struct kvm_vcpu vcpu); fastpath_t tdx_vcpu_run(struct kvm_vcpu vcpu, u64 run_flags); void tdx_prepare_switch_to_guest(struct kvm_vcpu vcpu); void tdx_vcpu_put(struct kvm_vcpu vcpu); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0f1a829032c06..d94b59140c452 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8867,7 +8867,15 @@ static int kvm_x86_vcpu_pre_run(struct kvm_vcpu vcpu) !kvm_apic_init_sipi_allowed(vcpu)) return -EINVAL; - return kvm_x86_call(vcpu_pre_run)(vcpu); + if (kvm_x86_call(vcpu_needs_initialization)(vcpu)) + return -EINVAL; + + if (kvm_x86_call(unhandleable_emulation_required)(vcpu)) { + kvm_prepare_emulation_failure_exit(vcpu); + return 0; + } + + return 1; } int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu vcpu) diff --git a/tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c b/tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c index 578283893ab37..c8379124b3172 100644 --- a/tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c +++ b/tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c @@ -2,6 +2,7 @@ #include "test_util.h" #include "kvm_util.h" #include "processor.h" +#include "smm.h" #include "vmx.h" #include <string.h> @@ -9,9 +10,23 @@ #include "kselftest.h" -#define ARBITRARY_IO_PORT 0x2000 +#define ARBITRARY_IO_PORT 0x80 -static struct kvm_vm vm; +/* + * The 64-bit SMRAM state-save area starts at SMBASE + 0xfe00. TR starts at + * offset 0xfe90, and attributes is the second 16-bit field in the descriptor. + / +#define SMRAM64_TR_ATTRIBUTES_OFFSET 0xfe92 +#define SMRAM_GPA 0x1000000 + +/ + * SMI handler that runs in 16-bit Real Mode. Syncs with L0 via port I/O, then + * executes RSM to trigger the consumption of invalid guest state. + / +static u8 smi_handler[] = { + 0xe4, ARBITRARY_IO_PORT, / IN $ARBITRARY_IO_PORT, %al / + 0x0f, 0xaa, / RSM / +}; static void l2_guest_code(void) { @@ -19,8 +34,9 @@ static void l2_guest_code(void) Generate an exit to L0 userspace, i.e. main(), via I/O to an * arbitrary port. / - asm volatile("inb %%dx, %%al" - : : [port] "d" (ARBITRARY_IO_PORT) : "rax"); + asm volatile("inb $" __stringify(ARBITRARY_IO_PORT) ", %%al" + ::: "rax"); + GUEST_FAIL("L2 resumed after stuffing invalid guest state"); } static void l1_guest_code(struct vmx_pages vmx_pages) @@ -46,35 +62,50 @@ static void l1_guest_code(struct vmx_pages vmx_pages) GUEST_DONE(); } -int main(int argc, char argv[]) +static void vcpu_run_to_io(struct kvm_vcpu vcpu, bool want_l2) { - gva_t vmx_pages_gva; - struct kvm_sregs sregs; - struct kvm_vcpu vcpu; - struct kvm_run run; - struct ucall uc; + struct kvm_run run = vcpu->run; - TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX)); + vcpu_run(vcpu); - vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code); + TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO); - /* Allocate VMX pages and shared descriptors (vmx_pages). / - vcpu_alloc_vmx(vm, &vmx_pages_gva); - vcpu_args_set(vcpu, 1, vmx_pages_gva); + TEST_ASSERT(run->io.port == ARBITRARY_IO_PORT && + (!!(run->flags & KVM_RUN_X86_GUEST_MODE) == want_l2 \|\| + !kvm_has_cap(KVM_CAP_X86_GUEST_MODE)), + "Expected IN from port 0x%x from L%u, got port 0x%x from L%u", + ARBITRARY_IO_PORT, 1 + want_l2, run->io.port, + 1 + !!(run->flags & KVM_RUN_X86_GUEST_MODE)); +} - vcpu_run(vcpu); +static struct kvm_vm vm_create_and_run_l2(struct kvm_vcpu *vcpu) +{ + gva_t vmx_pages_gva; + struct kvm_vm vm; + + vm = vm_create_with_one_vcpu(vcpu, l1_guest_code); - run = vcpu->run; + /* Allocate VMX pages and shared descriptors (vmx_pages). / + vcpu_alloc_vmx(vm, &vmx_pages_gva); + vcpu_args_set(vcpu, 1, vmx_pages_gva); /* * The first exit to L0 userspace should be an I/O access from L2. * Running L1 should launch L2 without triggering an exit to userspace. / - TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO); + vcpu_run_to_io(vcpu, true); - TEST_ASSERT(run->io.port == ARBITRARY_IO_PORT, - "Expected IN from port %d from L2, got port %d", - ARBITRARY_IO_PORT, run->io.port); + return vm; +} + +static void test_invalid_l2_guest_state(void) +{ + struct kvm_sregs sregs; + struct kvm_vcpu vcpu; + struct kvm_vm vm; + struct ucall uc; + + vm = vm_create_and_run_l2(&vcpu); /* * Stuff invalid guest state for L2 by making TR unusable. The next @@ -96,4 +127,49 @@ int main(int argc, char argv[]) default: TEST_FAIL("Unexpected ucall: %lu", uc.cmd); } + + kvm_vm_free(vm); +} + +static void test_invalid_l2_guest_state_rsm(void) +{ + struct kvm_vcpu vcpu; + struct kvm_vm vm; + u16 tr_attrs; + + if (!kvm_has_cap(KVM_CAP_X86_SMM)) + return; + + vm = vm_create_and_run_l2(&vcpu); + + /* + * Inject SMI while L2 is active, run the vCPU to get I/O exit from L1, + * then stuff TR in the SMRAM state-save area so that RSM restores + * invalid L2 state. + / + setup_smram(vm, vcpu, SMRAM_GPA, smi_handler, sizeof(smi_handler)); + inject_smi(vcpu); + + vcpu_run_to_io(vcpu, false); + + / Clear the present bit in SMRAM to make TR unusable. / + tr_attrs = addr_gpa2hva(vm, SMRAM_GPA + SMRAM64_TR_ATTRIBUTES_OFFSET); + tr_attrs &= ~BIT(7); + + vcpu_run(vcpu); + + /* + * For RSM, L1 gets the SHUTDOWN because RSM is architecturally defined + * to result in shutdown if the CPU detects invalid state in SMRAM. + / + TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_SHUTDOWN); + kvm_vm_free(vm); +} + +int main(int argc, char argv[]) +{ + TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX)); + + test_invalid_l2_guest_state(); + test_invalid_l2_guest_state_rsm(); }
3/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 8918 output: 35 thoughts: 776 Thoughts: Analyzing the KVM x86 Patch: Focus on Fuzzing Targets Okay, so I've got this patch in front of me that tweaks the KVM x86 operations. It's adding `vcpu_needs_initialization` and `unhandleable_emulation_required` to the `struct kvm_x86_ops`. I immediately see it's touching some core areas: `arch/x86/kvm/smm.c`, `arch/x86/kvm/svm/sev.c`, `arch/x86/kvm/svm/svm.c`, `arch/x86/kvm/vmx/main.c`, `arch/x86/kvm/vmx/tdx.c`, `arch/x86/kvm/vmx/vmx.c`, and `arch/x86/kvm/x86.c`. That means it's fundamentally changing how KVM deals with unhandleable emulation, especially when exiting SMM via the RSM instruction. Specifically, if `unhandleable_emulation_required` is set, it will return `X86EMUL_UNHANDLEABLE` within `emulator_leave_smm`. It looks like it's also refactoring the `vcpu_pre_run` logic, splitting it into `vcpu_needs_initialization` and that `unhandleable_emulation_required` flag. My first thought is, is this code even reachable and functional? Given the file changes, the answer is a resounding yes. It's modifying core KVM x86 logic, and it's definitely going to be active in environments like GCE or QEMU, since KVM is the underlying hypervisor. We know syzkaller is going to hit KVM hard with the `/dev/kvm` interface, so this is going to be tested for sure. Now, let's pinpoint the key functions for fuzzing. I need to figure out the specific parts that are new or changed: * `emulator_leave_smm` (modified) * `sev_vcpu_needs_initialization` * `vt_vcpu_needs_initialization` * `vt_unhandleable_emulation_required` * `tdx_vcpu_needs_initialization` * `vmx_unhandleable_emulation_required` * `kvm_x86_vcpu_pre_run` (modified) `emulator_leave_smm` jumps out immediately as a good target. I know that's called when emulating the RSM instruction, which is often a source of bugs in hypervisors. Then I note `kvm_x86_vcpu_pre_run` is a good one, but wait, it's a static function, according to the code, in `arch/x86/kvm/x86.c`... ah, no wait, `kvm_arch_vcpu_ioctl_run` calls it, which is the main entry for the `KVM_RUN` ioctl. It's a critical entry point. Okay, let's focus on `emulator_leave_smm`. I'll dig into it in `arch/x86/kvm/smm.c`. Then I'll check `vmx_unhandleable_emulation_required` and `tdx_vcpu_needs_initialization` to follow the path and check their usages. Now it's time to test, test, test. Time to fire up the tools and verify this thing.
4/2	2026/08/02 02:58	tool	grepper	0m Args: { "Expression": "emulator_leave_smm", "PathPrefix": "arch/x86/kvm/" } Results: { "Output": "arch/x86/kvm/smm.c=516=static int rsm_load_state_64(struct x86_emulate_ctxt ctxt,\n--\narch/x86/kvm/smm.c-572-\narch/x86/kvm/smm.c:573:int emulator_leave_smm(struct x86_emulate_ctxt ctxt)\narch/x86/kvm/smm.c-574-{\n--\narch/x86/kvm/smm.h=158=void enter_smm(struct kvm_vcpu vcpu);\narch/x86/kvm/smm.h:159:int emulator_leave_smm(struct x86_emulate_ctxt ctxt);\narch/x86/kvm/smm.h-160-void process_smi(struct kvm_vcpu vcpu);\n--\narch/x86/kvm/smm.h=163=static inline bool is_smm(struct kvm_vcpu vcpu) { return false; }\n--\narch/x86/kvm/smm.h-165-/\narch/x86/kvm/smm.h:166: emulator_leave_smm is used as a function pointer, so the\narch/x86/kvm/smm.h-167- * stub is defined in x86.c.\n--\narch/x86/kvm/x86.c=5754=static bool emulator_is_smm(struct x86_emulate_ctxt ctxt)\n--\narch/x86/kvm/x86.c-5759-#ifndef CONFIG_KVM_SMM\narch/x86/kvm/x86.c:5760:static int emulator_leave_smm(struct x86_emulate_ctxt ctxt)\narch/x86/kvm/x86.c-5761-{\n--\narch/x86/kvm/x86.c=5814=static const struct x86_emulate_ops emulate_ops = {\n--\narch/x86/kvm/x86.c-5856-\t.is_smm = emulator_is_smm,\narch/x86/kvm/x86.c:5857:\t.leave_smm = emulator_leave_smm,\narch/x86/kvm/x86.c-5858-\t.triple_fault = emulator_triple_fault,\n" }
5/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 11188 output: 35 thoughts: 193 Thoughts: Analyzing KVM Initialization and Configuration Okay, so I'm digging into some KVM code and noticing a pattern. It looks like `emulator_leave_smm` in `arch/x86/kvm/smm.c` is non-static, but only when `CONFIG_KVM_SMM` is enabled. That's immediately interesting, suggests a specific purpose related to SMM handling. Next, I see that `vmx_unhandleable_emulation_required` in `arch/x86/kvm/vmx/vmx.c` is also non-static. This likely means it's exported for use elsewhere within the KVM system, perhaps to indicate some kind of state or requirement during VMX operations. Then there are `tdx_vcpu_needs_initialization` in `arch/x86/kvm/vmx/tdx.c` and `sev_vcpu_needs_initialization` in `arch/x86/kvm/svm/sev.c`. Both of these are also non-static. The names are pretty self-explanatory, so I'm thinking they're flags or indicators for whether a VCPU needs some initialization specific to TDX or SEV. Given these observations, I should double check the Kconfig settings. I want to confirm how `CONFIG_KVM_SMM`, `CONFIG_KVM_AMD_SEV`, and `CONFIG_KVM_INTEL_TDX` (if it exists) are defined and related. This will help determine the compilation conditions for these non-static functions and provide a clearer picture of their use in the wider KVM architecture.
6/2	2026/08/02 02:58	tool	grepper	0m Args: { "Expression": "config KVM_SMM", "PathPrefix": "arch/x86/kvm/" } Results: { "Output": "arch/x86/kvm/Kconfig=173=config KVM_IOAPIC\n--\narch/x86/kvm/Kconfig-182-\narch/x86/kvm/Kconfig:183:config KVM_SMM\narch/x86/kvm/Kconfig-184-\tbool \"System Management Mode emulation\"\n" }
7/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 11880 output: 37 thoughts: 15 Thoughts: Okay, here's my interpretation of that thought process, assuming I'm an expert in virtualization, specifically KVM and AMD's Secure Encrypted Virtualization (SEV): Investigating AMD SEV Support in KVM Alright, I need to take a look at the KVM configuration. My immediate thought is to check for the `CONFIG_KVM_AMD_SEV` option. This is the critical flag; it indicates whether the KVM build includes support for AMD's Secure Encrypted Virtualization. Without it, SEV features are simply not available, and any attempt to utilize them will fail, or worse, silently degrade security. I need to make sure this is enabled; it’s fundamental to utilizing SEV's security benefits – protecting VM data even from the hypervisor itself. My next step will be to verify how it's defined and if there any dependencies that need to be in place.
8/2	2026/08/02 02:58	tool	grepper	0m Args: { "Expression": "config KVM_AMD_SEV", "PathPrefix": "arch/x86/kvm/" } Results: { "Output": "arch/x86/kvm/Kconfig=146=config KVM_AMD\n--\narch/x86/kvm/Kconfig-155-\narch/x86/kvm/Kconfig:156:config KVM_AMD_SEV\narch/x86/kvm/Kconfig-157-\tbool \"AMD Secure Encrypted Virtualization (SEV) support\"\n" }
9/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 12236 output: 35 thoughts: 19 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Investigating Intel TDX Support Alright, before diving too deep, I need to quickly ascertain if we're dealing with a system that supports Intel Trust Domain Extensions (TDX). My initial thought is to check for the `CONFIG_KVM_INTEL_TDX` kernel configuration option. This would be the most straightforward indicator. I might also expand this search to include related, though possibly less specific, configuration flags. This immediate check will save a lot of time by telling me if TDX is even on the table. If that's the case, I will need to consider the next steps, maybe to investigate further or to dig into more subtle differences in the code. I just want a quick pointer to tell me where to go next.
10/2	2026/08/02 02:58	tool	grepper	0m Args: { "Expression": "config KVM_INTEL", "PathPrefix": "arch/x86/kvm/" } Results: { "Output": "arch/x86/kvm/Kconfig=83=config KVM_SW_PROTECTED_VM\n--\narch/x86/kvm/Kconfig-95-\narch/x86/kvm/Kconfig:96:config KVM_INTEL\narch/x86/kvm/Kconfig-97-\ttristate \"KVM for Intel (and compatible) processors support\"\n--\narch/x86/kvm/Kconfig-106-\narch/x86/kvm/Kconfig:107:config KVM_INTEL_PROVE_VE\narch/x86/kvm/Kconfig-108- bool \"Check that guests do not receive #VE exceptions\"\n--\narch/x86/kvm/Kconfig=122=config X86_SGX_KVM\n--\narch/x86/kvm/Kconfig-133-\narch/x86/kvm/Kconfig:134:config KVM_INTEL_TDX\narch/x86/kvm/Kconfig-135-\tbool \"Intel Trust Domain Extensions (TDX) support\"\n" }
11/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 12755 output: 37 thoughts: 50 Thoughts: Okay, let's break this down. Checking the KVM Configuration for Intel TDX Right, so we're dealing with these specific KVM features: `KVM_SMM`, `KVM_AMD_SEV`, and `KVM_INTEL_TDX`. The immediate question that jumps to mind is whether `KVM_INTEL_TDX` is actually the correct configuration we're looking for, or if we need to assess the whole suite to properly use the target feature. It seems logical to start there. So, let's determine if this is the right config and what other configurations may relate or are required. This is the logical first step in troubleshooting or configuring a system to use TDX.
12/2	2026/08/02 02:58	tool	grepper	0m Args: { "Expression": "depends on.KVM_INTEL", "PathPrefix": "arch/x86/kvm/" } Results:* { "Output": "arch/x86/kvm/Kconfig=107=config KVM_INTEL_PROVE_VE\narch/x86/kvm/Kconfig-108- bool \"Check that guests do not receive #VE exceptions\"\narch/x86/kvm/Kconfig:109: depends on KVM_INTEL \u0026\u0026 EXPERT\narch/x86/kvm/Kconfig-110- help\n--\narch/x86/kvm/Kconfig=122=config X86_SGX_KVM\narch/x86/kvm/Kconfig-123-\tbool \"Software Guard eXtensions (SGX) Virtualization\"\narch/x86/kvm/Kconfig:124:\tdepends on X86_SGX \u0026\u0026 KVM_INTEL\narch/x86/kvm/Kconfig-125-\thelp\n" }
13/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 13229 output: 39 thoughts: 33 Thoughts: Here's my thought process, as if I were considering this issue: Delving into the Dependencies of KVM_INTEL_TDX Okay, so `KVM_INTEL_TDX`. Right. What exactly are the dependencies on that? I need to understand what other components or settings it hinges on, because if I'm going to configure this properly, I need the complete picture. Let's see... I'll dive straight into `arch/x86/kvm/Kconfig`. That's where all the architecture-specific kernel configuration options usually live, so that's the logical starting point to trace those dependencies. I’m betting the answer is buried in there somewhere. Let's get to it.
14/2	2026/08/02 02:58	tool	read-file	0m Args: { "File": "arch/x86/kvm/Kconfig", "FirstLine": 130, "LineCount": 20 } Results: { "Contents": " 130:\t\t guests via a device node, e.g. /dev/sgx_vepc.\n 131:\t\n 132:\t\t If unsure, say N.\n 133:\t\n 134:\tconfig KVM_INTEL_TDX\n 135:\t\tbool \"Intel Trust Domain Extensions (TDX) support\"\n 136:\t\tdefault y\n 137:\t\tdepends on INTEL_TDX_HOST\n 138:\t\tselect KVM_GENERIC_MEMORY_ATTRIBUTES\n 139:\t\tselect HAVE_KVM_ARCH_GMEM_POPULATE\n 140:\t\thelp\n 141:\t\t Provides support for launching Intel Trust Domain Extensions (TDX)\n 142:\t\t confidential VMs on Intel processors.\n 143:\t\n 144:\t\t If unsure, say N.\n 145:\t\n 146:\tconfig KVM_AMD\n 147:\t\ttristate \"KVM for AMD processors support\"\n 148:\t\tdepends on KVM \u0026\u0026 (CPU_SUP_AMD \|\| CPU_SUP_HYGON)\n 149:\t\thelp\n" }
15/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 13761 output: 39 thoughts: 36 Thoughts: Okay, here's my take on those thoughts, framed as an expert's internal monologue: Dependency Graph Deep Dive Alright, let's see, the `KVM_INTEL_TDX` configuration option relies on `INTEL_TDX_HOST`, which makes perfect sense given the architecture. Now, let me quickly pivot and refresh my memory on the AMD side. I need to understand what the relationship is with `KVM_AMD_SEV`. I want to cross-reference and verify my current mental model of the interdependencies in these virtualization technologies. I should probably review the upstream changes too, to identify any recent relevant developments or bugfixes. This might also provide clues about how the Intel and AMD implementations are converging, or diverging, over time.
16/2	2026/08/02 02:58	tool	read-file	0m Args: { "File": "arch/x86/kvm/Kconfig", "FirstLine": 150, "LineCount": 20 } Results: { "Contents": " 150:\t\t Provides support for KVM on AMD processors equipped with the AMD-V\n 151:\t\t (SVM) extensions.\n 152:\t\n 153:\t\t To compile this as a module, choose M here: the module\n 154:\t\t will be called kvm-amd.\n 155:\t\n 156:\tconfig KVM_AMD_SEV\n 157:\t\tbool \"AMD Secure Encrypted Virtualization (SEV) support\"\n 158:\t\tdefault y\n 159:\t\tdepends on KVM_AMD \u0026\u0026 X86_64\n 160:\t\tdepends on CRYPTO_DEV_SP_PSP \u0026\u0026 !(KVM_AMD=y \u0026\u0026 CRYPTO_DEV_CCP_DD=m)\n 161:\t\tselect ARCH_HAS_CC_PLATFORM\n 162:\t\tselect KVM_GENERIC_MEMORY_ATTRIBUTES\n 163:\t\tselect HAVE_KVM_ARCH_GMEM_CONVERT\n 164:\t\tselect HAVE_KVM_ARCH_GMEM_RECLAIM\n 165:\t\tselect HAVE_KVM_ARCH_GMEM_INVALIDATE\n 166:\t\tselect HAVE_KVM_ARCH_GMEM_POPULATE\n 167:\t\thelp\n 168:\t\t Provides support for launching encrypted VMs which use Secure\n 169:\t\t Encrypted Virtualization (SEV), Secure Encrypted Virtualization with\n" }
17/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 14361 output: 39 thoughts: 48 Thoughts: Okay, here's my interpretation of those thoughts, presented as my own mental process, given my expertise: Checking Dependencies for KVM_AMD_SEV and Related Modules Alright, I see the dependency tree for `KVM_AMD_SEV`. It's pretty clear that it leverages `KVM_AMD`, is built for `X86_64` architectures, and needs `CRYPTO_DEV_SP_PSP` for its cryptographic operations. Seems logical, given SEV's security features. Now, before I dive deeper into the details of SEV, I want to quickly check the status and dependencies of `KVM_SMM` as a preliminary. Understanding its relationship to other KVM components, particularly on AMD platforms, is always a good starting point. It may be key to a holistic architecture review.
18/2	2026/08/02 02:58	tool	read-file	0m Args: { "File": "arch/x86/kvm/Kconfig", "FirstLine": 180, "LineCount": 20 } Results: { "Contents": " 180:\t\n 181:\t\t If unsure, say Y.\n 182:\t\n 183:\tconfig KVM_SMM\n 184:\t\tbool \"System Management Mode emulation\"\n 185:\t\tdefault y\n 186:\t\tdepends on KVM_X86\n 187:\t\thelp\n 188:\t\t Provides support for KVM to emulate System Management Mode (SMM)\n 189:\t\t in virtual machines. This can be used by the virtual machine\n 190:\t\t firmware to implement UEFI secure boot.\n 191:\t\n 192:\t\t If unsure, say Y.\n 193:\t\n 194:\tconfig KVM_HYPERV\n 195:\t\tbool \"Support for Microsoft Hyper-V emulation\"\n 196:\t\tdepends on KVM_X86\n 197:\t\tdefault y\n 198:\t\thelp\n 199:\t\t Provides KVM support for emulating Microsoft Hyper-V. This allows KVM\n" }
19/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 14900 output: 34 thoughts: 41 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Analyzing Hardware Virtualization Extensions Okay, so I'm looking at these KVM-related extensions: `KVM_SMM`, `KVM_AMD_SEV`, and `KVM_INTEL_TDX`. Immediately, the presence of these three indicates that we're talking about specific hardware virtualization capabilities and potential security enhancements. `KVM_SMM` likely deals with System Management Mode interaction within the virtualized environment. `KVM_AMD_SEV` definitely relates to AMD's Secure Encrypted Virtualization, a crucial feature for data confidentiality and integrity in VMs. And then we have `KVM_INTEL_TDX`. Given the context, that's almost certainly Intel's Trust Domain Extensions. My immediate thought is to delve deeper into `INTEL_TDX_HOST`. I need to understand the host side implementation and implications. What are the specific aspects that they want me to focus on? What's the context? Let's check `INTEL_TDX_HOST`.
20/2	2026/08/02 02:58	tool	grepper	0m Args: { "Expression": "config INTEL_TDX_HOST", "PathPrefix": "arch/x86/" } Results: { "Output": "arch/x86/Kconfig=1844=config X86_USER_SHADOW_STACK\n--\narch/x86/Kconfig-1863-\narch/x86/Kconfig:1864:config INTEL_TDX_HOST\narch/x86/Kconfig-1865-\tbool \"Intel Trust Domain Extensions (TDX) host support\"\n" }
21/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 15316 output: 37 thoughts: 17 Thoughts: Okay, let's dive into this. Here's how I'd approach that line of thought, tailored for someone who's already deep in the weeds like myself: Investigating the Dependencies of INTEL_TDX_HOST Right, let's see what we're dealing with here. INTEL_TDX_HOST. Sounds like it's a key component for TDX (Trust Domain Extensions) on the host side. I need to understand its dependencies, specifically from a system design and integration perspective. I'm thinking, "what are the building blocks that INTEL_TDX_HOST relies on to function? What libraries, kernel modules, or other pieces of the infrastructure does this component need?" Perhaps it requires specific hardware features, firmware revisions, or interactions with the BIOS. My primary question is this: "Where does this fit in the overall architecture?" I need to understand its relationship to the trusted environment, the host's operating system, and potentially any virtualization layers in play. Knowing its dependencies will give me a better understanding of potential integration points, compatibility concerns, and the implications of any configuration changes. Let's see what the documentation tells us about what the code is doing or requires.
22/2	2026/08/02 02:58	tool	read-file	0m Args: { "File": "arch/x86/Kconfig", "FirstLine": 1860, "LineCount": 20 } Results: { "Contents": "1860:\t\t See Documentation/arch/x86/shstk.rst for more information.\n1861:\t\n1862:\t\t If unsure, say N.\n1863:\t\n1864:\tconfig INTEL_TDX_HOST\n1865:\t\tbool \"Intel Trust Domain Extensions (TDX) host support\"\n1866:\t\tdepends on CPU_SUP_INTEL\n1867:\t\tdepends on X86_64\n1868:\t\tdepends on KVM_INTEL\n1869:\t\tdepends on X86_X2APIC\n1870:\t\tselect ARCH_KEEP_MEMBLOCK\n1871:\t\tdepends on CONTIG_ALLOC\n1872:\t\tdepends on X86_MCE\n1873:\t\thelp\n1874:\t\t Intel Trust Domain Extensions (TDX) protects guest VMs from malicious\n1875:\t\t host and certain physical attacks. This option enables necessary TDX\n1876:\t\t support in the host kernel to run confidential VMs.\n1877:\t\n1878:\t\t If unsure, say N.\n1879:\t\n" }
23/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 15928 output: 33 thoughts: 74 Thoughts: Okay, here's my interpretation of those dependencies, as if they were my own immediate thoughts as an expert in the field: Dependency Deep Dive Alright, let's break this down. My initial observation is that `INTEL_TDX_HOST` hinges on a handful of critical prerequisites. It's built upon the foundation of `CPU_SUP_INTEL`, of course, that's expected for any Intel-specific feature. `X86_64` is fundamental; 64-bit architecture is a given in this context. `KVM_INTEL` is crucial, given that we are discussing virtualization extensions. Furthermore, `X86_X2APIC` is also a critical dependency; this points to Advanced Programmable Interrupt Controller (APIC) usage, which is key for efficient interrupt handling in modern multi-core systems, especially in a virtualized environment. `CONTIG_ALLOC` is necessary as contiguous memory allocation is an important component for the isolation process that TDX provides. Finally, `X86_MCE`, or Machine Check Exception support, plays a key part in the reliability and error handling, ensuring robust operation within this secure environment. Now, I'm going to shift gears and delve into `CRYPTO_DEV_SP_PSP`. This will be another set of dependencies. Let's see what that entails...
24/2	2026/08/02 02:58	tool	grepper	0m Args: { "Expression": "config CRYPTO_DEV_SP_PSP", "PathPrefix": "drivers/crypto/" } Results: { "Output": "drivers/crypto/ccp/Kconfig=23=config CRYPTO_DEV_CCP_CRYPTO\n--\ndrivers/crypto/ccp/Kconfig-37-\ndrivers/crypto/ccp/Kconfig:38:config CRYPTO_DEV_SP_PSP\ndrivers/crypto/ccp/Kconfig-39-\tbool \"Platform Security Processor (PSP) device\"\n" }
25/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 16424 output: 36 thoughts: 16 Thoughts: Okay, let's dive into this. Here's my summary, taking the first-person perspective as requested: Dependency Check: CRYPTO_DEV_SP_PSP Alright, I need to get a handle on the current state of things. My primary focus right now is the `CRYPTO_DEV_SP_PSP` module. Before I proceed any further, and to ensure I’m operating in a safe and effective manner, I have to first meticulously examine its dependencies. This is crucial. I need to understand what other components, libraries, or services it relies upon. I'm thinking I'll start by creating a comprehensive dependency graph to visualize the connections. Are there any critical vulnerabilities in the dependencies? This could mean potential security risks. Do they require specific versions, or am I dealing with backwards compatibility issues? This is a core part of my evaluation of the system. I have to make sure that any updates or changes I'm considering won't inadvertently break existing functionalities. Let's start digging.
26/2	2026/08/02 02:58	tool	read-file	0m Args: { "File": "drivers/crypto/ccp/Kconfig", "FirstLine": 35, "LineCount": 20 } Results: { "Contents": " 35:\t\t Coprocessor. This module supports offload of SHA and AES algorithms.\n 36:\t\t If you choose 'M' here, this module will be called ccp_crypto.\n 37:\t\n 38:\tconfig CRYPTO_DEV_SP_PSP\n 39:\t\tbool \"Platform Security Processor (PSP) device\"\n 40:\t\tdefault y\n 41:\t\tdepends on CRYPTO_DEV_CCP_DD \u0026\u0026 X86_64 \u0026\u0026 AMD_IOMMU\n 42:\t\tselect PCI_TSM if PCI\n 43:\t\thelp\n 44:\t\t Provide support for the AMD Platform Security Processor (PSP).\n 45:\t\t The PSP is a dedicated processor that provides support for key\n 46:\t\t management commands in Secure Encrypted Virtualization (SEV) mode,\n 47:\t\t along with software-based Trusted Execution Environment (TEE) to\n 48:\t\t enable third-party trusted applications.\n 49:\t\n 50:\tconfig CRYPTO_DEV_CCP_DEBUGFS\n 51:\t\tbool \"Enable CCP Internals in DebugFS\"\n 52:\t\tdefault n\n 53:\t\tdepends on CRYPTO_DEV_SP_CCP\n 54:\t\thelp\n" }
27/2	2026/08/02 02:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 16996 output: 35 thoughts: 53 Thoughts: Okay, here's my interpretation of that thought process, assuming I'm an expert in this area and this is a brief mental note: Dependencies and Verification Right, so `CRYPTO_DEV_SP_PSP` is contingent on `CRYPTO_DEV_CCP_DD`, `X86_64`, and `AMD_IOMMU`. That makes sense; it's likely a security-focused module or subsystem that requires certain hardware and underlying cryptographic services. Now, given that dependency chain, the next logical step is to verify the state of `CRYPTO_DEV_CCP_DD`. I need to ensure that the core component it relies upon is configured correctly, because the configuration of that component directly dictates the potential configurations of the components which are dependent upon it. I must check on `CRYPTO_DEV_CCP_DD` to see if that's configured properly.
28/2	2026/08/02 02:59	tool	read-file	0m Args: { "File": "drivers/crypto/ccp/Kconfig", "FirstLine": 1, "LineCount": 20 } Results: { "Contents": " 1:\t# SPDX-License-Identifier: GPL-2.0-only\n 2:\tconfig CRYPTO_DEV_CCP_DD\n 3:\t\ttristate \"Secure Processor device driver\"\n 4:\t\tdepends on CPU_SUP_AMD \|\| ARM64\n 5:\t\tdefault m\n 6:\t\thelp\n 7:\t\t Provides AMD Secure Processor device driver.\n 8:\t\t If you choose 'M' here, this module will be called ccp.\n 9:\t\n 10:\tconfig CRYPTO_DEV_SP_CCP\n 11:\t\tbool \"Cryptographic Coprocessor device\"\n 12:\t\tdefault y\n 13:\t\tdepends on CRYPTO_DEV_CCP_DD \u0026\u0026 DMADEVICES\n 14:\t\tselect HW_RANDOM\n 15:\t\tselect DMA_ENGINE\n 16:\t\tselect CRYPTO_SHA1\n 17:\t\tselect CRYPTO_SHA256\n 18:\t\thelp\n 19:\t\t Provides the support for AMD Cryptographic Coprocessor (CCP) device\n 20:\t\t which can be used to offload encryption operations such as SHA, AES\n" }
29/2	2026/08/02 02:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 17553 output: 42 thoughts: 723 Thoughts: My Analysis of KVM Configuration and Focus Symbols Right, so I need to nail down the essential configurations. The initial list includes `KVM_SMM`, `KVM_AMD_SEV`, `KVM_INTEL_TDX`, `INTEL_TDX_HOST`, `CRYPTO_DEV_SP_PSP`, and `CRYPTO_DEV_CCP_DD`. But hang on, `KVM_SMM` is already enabled by default, and the other two, `KVM_AMD_SEV` and `KVM_INTEL_TDX` are also likely enabled by default, contingent on dependencies. So, the essential configs will be these six. Now, let's look at the focus symbols, these are key: `emulator_leave_smm`, `sev_vcpu_needs_initialization`, `tdx_vcpu_needs_initialization`, and `vmx_unhandleable_emulation_required`. I need to ensure these are reachable, not static, and relevant. I've verified that all the symbols are indeed non-static: `emulator_leave_smm` is in `arch/x86/kvm/smm.c`, `sev_vcpu_needs_initialization` in `arch/x86/kvm/svm/sev.c`, `tdx_vcpu_needs_initialization` in `arch/x86/kvm/vmx/tdx.c`, and `vmx_unhandleable_emulation_required` in `arch/x86/kvm/vmx/vmx.c`. Perfect. Those two other vmx symbols are static, so I can ignore those. Now, the important part: are these useful symbols? `emulator_leave_smm` is triggered when executing an RSM instruction which is used to leave SMM, so that is a good starting point. Makes sense. `sev_vcpu_needs_initialization` is very interesting, because it's called from `kvm_x86_vcpu_pre_run`, which is called from `kvm_arch_vcpu_ioctl_run`. That's the main loop for running a vCPU! So, it’s executed on every `KVM_RUN` ioctl, a hot-path function. The question is: is `kvm_x86_vcpu_pre_run` always called? That needs confirmation, and could be a very valuable place to focus attention for optimization or debugging.
30/2	2026/08/02 02:59	tool	grepper	0m Args: { "Expression": "kvm_x86_vcpu_pre_run", "PathPrefix": "arch/x86/kvm/" } Results: { "Output": "arch/x86/kvm/x86.c=8800=static int complete_emulated_mmio(struct kvm_vcpu vcpu)\n--\narch/x86/kvm/x86.c-8843-\narch/x86/kvm/x86.c:8844:static int kvm_x86_vcpu_pre_run(struct kvm_vcpu vcpu)\narch/x86/kvm/x86.c-8845-{\n--\narch/x86/kvm/x86.c=8881=int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/x86.c-8981-\narch/x86/kvm/x86.c:8982:\tr = kvm_x86_vcpu_pre_run(vcpu);\narch/x86/kvm/x86.c-8983-\tif (r \u003c= 0)\n" }
31/2	2026/08/02 02:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 19153 output: 45 thoughts: 649 Thoughts: Analyzing Hot-Path Functions and Potential Fuzzing Targets Okay, so I'm looking at how this new code integrates into the KVM x86 architecture. I see that `kvm_x86_vcpu_pre_run` is called right at the start of `kvm_arch_vcpu_ioctl_run`. That means functions like `sev_vcpu_needs_initialization` and `tdx_vcpu_needs_initialization` are being called every time a `KVM_RUN` ioctl is issued. Those are definitely hot-path functions, but the instructions say to avoid listing those to prevent skewing test distributions. Makes sense. Fuzzing a simple boolean return isn't going to be super fruitful anyway. Alright, what else is called from that pre-run function? Ah, `vmx_unhandleable_emulation_required`. It's also called from there, via `unhandleable_emulation_required` op. So again, hot-path. Gotta avoid that one. Wait, now I see that `vmx_unhandleable_emulation_required` is also called from `emulator_leave_smm`. Aha! That's interesting. Looking at the code: ```c if (ret == X86EMUL_CONTINUE && kvm_x86_call(unhandleable_emulation_required)(vcpu)) ret = X86EMUL_UNHANDLEABLE; ``` It's being called inside `emulator_leave_smm`. So, the question is: is that a hot-path function? No, `emulator_leave_smm` is only called when executing the RSM instruction. That's a great candidate! That's where the new functionality is. Now, let me make sure I'm understanding this correctly. `vmx_unhandleable_emulation_required` is hot-path. The original logic was calling it from `kvm_x86_vcpu_pre_run`. The patch just refactored and renamed the op to call from `kvm_x86_vcpu_pre_run` and also from `emulator_leave_smm`. So the new logic is in `emulator_leave_smm`. Let's double check that. Yep, `emulator_leave_smm` seems to be the main functional change in this patch. The rest is refactoring to allow calling `unhandleable_emulation_required` from the new entry point. So, in summary, fuzzing `emulator_leave_smm` seems like the best approach here.
32/2	2026/08/02 02:59	tool	read-file	0m Args: { "File": "arch/x86/kvm/vmx/vmx.c", "FirstLine": 6030, "LineCount": 20 } Results: { "Contents": "6030:\t\treturn 1;\n6031:\t}\n6032:\t\n6033:\t/\n6034:\t Returns true if emulation is required (due to the vCPU having invalid state\n6035:\t * with unsrestricted guest mode disabled) and KVM can't faithfully emulate the\n6036:\t * current vCPU state.\n6037:\t /\n6038:\tbool vmx_unhandleable_emulation_required(struct kvm_vcpu vcpu)\n6039:\t{\n6040:\t\tstruct vcpu_vmx vmx = to_vmx(vcpu);\n6041:\t\n6042:\t\tif (!vmx-\u003evt.emulation_required)\n6043:\t\t\treturn false;\n6044:\t\n6045:\t\t/\n6046:\t\t * It is architecturally impossible for emulation to be required when a\n6047:\t\t * nested VM-Enter is pending completion, as VM-Enter will VM-Fail if\n6048:\t\t * guest state is invalid and unrestricted guest is disabled, i.e. KVM\n6049:\t\t * should synthesize VM-Fail instead emulation L2 code. This path is\n" }
33/2	2026/08/02 02:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 20750 output: 36 thoughts: 720 Thoughts: Analyzing the Configuration Requirements for a KVM Patch Okay, so this `vmx_unhandleable_emulation_required` flag is just a simple check, nothing complex there. The patch adds a test, specifically `tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c`, which seems to be the core of what's being tested. The test's logic is all about injecting an SMI while L2 is running, forcing an I/O exit from L1, manipulating TR in the SMRAM state-save area, and then expecting a SHUTDOWN exit due to invalid L2 state on RSM. This is a very clear test of that new `emulator_leave_smm` logic. That makes `emulator_leave_smm` the key function. My focus is entirely there. Now, let's nail down the config options. Is `KVM_SMM` sufficient? Well, this test is VMX-specific, so clearly `KVM_INTEL` is a must-have. And since the test specifically targets `emulator_leave_smm`, `KVM_SMM` is essential. The refactored code needs `KVM_AMD_SEV` and `KVM_INTEL_TDX` to compile and be tested too. Let's list these dependencies explicitly: * `KVM_SMM` * `KVM_AMD_SEV` * `KVM_INTEL_TDX` * `INTEL_TDX_HOST` * `CRYPTO_DEV_SP_PSP` * `CRYPTO_DEV_CCP_DD` Hold on, do we also need `KVM_INTEL` and `KVM_AMD` explicitly? They are usually enabled in syzkaller by default, but there's no harm in including them, just in case. They are tristate, so specifying them won't be an issue. Wait, a bit more digging. It looks like `KVM_INTEL_TDX` depends on `INTEL_TDX_HOST`, which in turn depends on `KVM_INTEL`, and `KVM_AMD_SEV` depends on `KVM_AMD`. So, we're good there. Just to be sure, is `KVM_SMM` a default-enabled option? Yes, it is set to `default y`, but it's still prudent to specify it directly. Okay, is `emulator_leave_smm` truly the only function of interest? Are there any others that are not performance-critical? Let's check. Ah, `sev_vcpu_needs_initialization` and `tdx_vcpu_needs_initialization` and `vmx_unhandleable_emulation_required` are performance-critical. So, yes, `emulator_leave_smm` is the only focus here. Finally, is `emulator_leave_smm` exported, or is it static? It's non-static in `arch/x86/kvm/smm.c`. But hold on, if `CONFIG_KVM_SMM` is not defined in `arch/x86/kvm/x86.c`, it's defined as static inline or static. However, with `CONFIG_KVM_SMM=y`, it's indeed non-static in `smm.c`. Therefore, let me just double-check `emulator_leave_smm` in `smm.c` for correctness.
34/2	2026/08/02 02:59	tool	grepper	0m Args: { "Expression": "int emulator_leave_smm", "PathPrefix": "arch/x86/kvm/" } Results: { "Output": "arch/x86/kvm/smm.c=516=static int rsm_load_state_64(struct x86_emulate_ctxt ctxt,\n--\narch/x86/kvm/smm.c-572-\narch/x86/kvm/smm.c:573:int emulator_leave_smm(struct x86_emulate_ctxt ctxt)\narch/x86/kvm/smm.c-574-{\n--\narch/x86/kvm/smm.h=158=void enter_smm(struct kvm_vcpu vcpu);\narch/x86/kvm/smm.h:159:int emulator_leave_smm(struct x86_emulate_ctxt ctxt);\narch/x86/kvm/smm.h-160-void process_smi(struct kvm_vcpu vcpu);\n--\narch/x86/kvm/x86.c=5754=static bool emulator_is_smm(struct x86_emulate_ctxt ctxt)\n--\narch/x86/kvm/x86.c-5759-#ifndef CONFIG_KVM_SMM\narch/x86/kvm/x86.c:5760:static int emulator_leave_smm(struct x86_emulate_ctxt *ctxt)\narch/x86/kvm/x86.c-5761-{\n" }
35/2	2026/08/02 02:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 22674 output: 32 thoughts: 794 Thoughts: Analyzing the RSM Instruction Emulation Patch Okay, so I've been digging into this patch related to the RSM instruction emulation within KVM. My initial observation is that the core change resides in `emulator_leave_smm` within `smm.c`. I confirmed that the primary function of interest, `emulator_leave_smm`, is indeed not static, which is good for instrumentation. I did a quick scan of `smm.c` and noted that `rsm_load_state_32` and `rsm_load_state_64` are static, and `emulator_leave_smm` is, of course, the entry point for handling the RSM instruction. The meat of the patch introduces a check within `emulator_leave_smm`. Specifically, it calls a function, `unhandleable_emulation_required`, and, if this function returns true, the routine returns `X86EMUL_UNHANDLEABLE`. I see that the patch's purpose is to deal with invalid guest state during an RSM transition, which could potentially cause issues. The rest of the patch appears to be refactoring. It moves the initialization check logic into `vcpu_needs_initialization`, and it makes `unhandleable_emulation_required` available as a separate operation to support this new check. The logic seems straightforward: handle potentially unhandleable scenarios during RSM. Therefore, from a testing perspective, `emulator_leave_smm` is the key target. The new condition introduced by the patch should be the focus of fuzzing efforts. Now, for configuring a testing environment, I'm going to look at some key Kconfig options. It looks like the patch is dependent on some specific features. I'll need to enable `KVM_SMM`, `KVM_AMD_SEV`, `KVM_INTEL_TDX`, `INTEL_TDX_HOST`, `CRYPTO_DEV_SP_PSP`, `CRYPTO_DEV_CCP_DD`, `KVM_INTEL`, and `KVM_AMD`. I've double-checked that all of these are present and enabled. I'm making a mental note that `KVM_INTEL_TDX` and `INTEL_TDX_HOST` might not be in every kernel version, but they are available here. For a more comprehensive setup, and to minimize the risk of missing something, I'll also add a few standard configurations: `X86_64`, `CPU_SUP_INTEL`, `CPU_SUP_AMD`, `X86_X2APIC`, `CONTIG_ALLOC`, `X86_MCE`. Additionally, I'll enable `AMD_IOMMU` to ensure that `CRYPTO_DEV_SP_PSP` functions correctly. This should provide a reasonable starting point for testing this patch.
36/2	2026/08/02 02:59	tool	grepper	0m Args: { "Expression": "config AMD_IOMMU", "PathPrefix": "drivers/iommu/" } Results: { "Output": "drivers/iommu/amd/Kconfig-2-# AMD IOMMU support\ndrivers/iommu/amd/Kconfig:3:config AMD_IOMMU\ndrivers/iommu/amd/Kconfig-4-\tbool \"AMD IOMMU support\"\n--\ndrivers/iommu/amd/Kconfig-32-\ndrivers/iommu/amd/Kconfig:33:config AMD_IOMMU_IOMMUFD\ndrivers/iommu/amd/Kconfig-34-\tbool \"Enable IOMMUFD features for AMD IOMMU (EXPERIMENTAL)\"\n--\ndrivers/iommu/amd/Kconfig-42-\ndrivers/iommu/amd/Kconfig:43:config AMD_IOMMU_DEBUGFS\ndrivers/iommu/amd/Kconfig-44-\tbool \"Enable AMD IOMMU internals in DebugFS\"\n" }
37/2	2026/08/02 02:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 24336 output: 27 thoughts: 202 Thoughts: Refining the Configuration for a Secure KVM Environment Alright, the system definitely has `AMD_IOMMU`, which is a good starting point. Now, let's get into the details of the configuration, as this is going to be my thought process for setting up a secure KVM environment. I'm going to refine this list to make it a bit more complete, and I'll include things that I know are important for this specific scenario: `KVM_SMM`, that's a necessity `KVM_AMD_SEV` is definitely important with AMD IOMMU `KVM_INTEL_TDX`, let's add that for completeness `INTEL_TDX_HOST`, that one too. `CRYPTO_DEV_SP_PSP` will be useful `CRYPTO_DEV_CCP_DD`, I can see those two being useful in conjunction. `KVM_INTEL` and `KVM_AMD`, basic KVM, of course. `AMD_IOMMU`, again, just making sure. Okay, now let's think critically about the implications of including `KVM_INTEL_TDX` . I remember that it depends on `INTEL_TDX_HOST`, and that in turn depends on `X86_X2APIC`, `CONTIG_ALLOC`, and `X86_MCE`. Hmm, I should probably add those dependencies to the config just to be safe and ensure everything's properly enabled. I want to make sure the environment is solid, and I'm not chasing down some obscure dependency later. So let's add: `X86_X2APIC` `CONTIG_ALLOC` `X86_MCE` Now let's just make sure `CONTIG_ALLOC` is actually configured correctly and then review.
38/2	2026/08/02 02:59	tool	grepper	0m Args: { "Expression": "config CONTIG_ALLOC", "PathPrefix": "mm/" } Results: { "Output": "mm/Kconfig=709=config HUGETLB_PAGE_SIZE_VARIABLE\n--\nmm/Kconfig-718-\nmm/Kconfig:719:config CONTIG_ALLOC\nmm/Kconfig-720-\tdef_bool (MEMORY_ISOLATION \u0026\u0026 COMPACTION) \|\| CMA\n" }
39/2	2026/08/02 02:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 25052 output: 24 thoughts: 49 Thoughts: My Thinking on CONTIG_ALLOC Okay, so `CONTIG_ALLOC` is a `def_bool`, which means I don't get direct control over whether it's enabled. It's conditionally dependent, and right now, the logic is tied to `MEMORY_ISOLATION && COMPACTION` or `CMA`. Hmm, rather than untangling a more complex conditional, it looks like `CMA` is the simplest path to get this functionality. Therefore, I'll go ahead and just add a direct dependency on `CMA`. That's the most expedient and likely the most reliable approach at this juncture.
40/2	2026/08/02 02:59	tool	grepper	0m Args: { "Expression": "config CMA", "PathPrefix": "mm/" } Results: { "Output": "mm/Kconfig=1064=config HAVE_SETUP_PER_CPU_AREA\n--\nmm/Kconfig-1066-\nmm/Kconfig:1067:config CMA\nmm/Kconfig-1068-\tbool \"Contiguous Memory Allocator\"\n--\nmm/Kconfig-1081-\nmm/Kconfig:1082:config CMA_DEBUGFS\nmm/Kconfig-1083-\tbool \"CMA debugfs interface\"\n--\nmm/Kconfig-1087-\nmm/Kconfig:1088:config CMA_SYSFS\nmm/Kconfig-1089-\tbool \"CMA information through sysfs interface\"\n--\nmm/Kconfig-1094-\nmm/Kconfig:1095:config CMA_AREAS\nmm/Kconfig-1096-\tint \"Maximum count of the CMA areas\"\n" }
41/2	2026/08/02 02:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 25487 output: 35 thoughts: 21 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Analyzing the Landscape Alright, let's zero in on this problem. First, I need to consider `CMA` – Contiguous Memory Allocator. This suggests a potential focus on memory management and potentially a challenge around fragmentation, large allocations, or perhaps NUMA considerations. I need to keep that in mind as I dig deeper. Next, I need to check `X86_X2APIC`. This is clearly indicating an x86 architecture with the X2APIC feature enabled. This immediately implies a scale of potential performance implications - think interrupt handling, IPI performance, and the implications on synchronization primitives. It also implies a certain level of system configuration - core count, BIOS settings, and OS kernel options will need to be understood in order to understand how these elements interrelate. I'll need to understand how these two, `CMA` and `X86_X2APIC`, might interact or conflict. The implications are potentially profound.
42/2	2026/08/02 02:59	tool	grepper	0m Args: { "Expression": "config X86_X2APIC", "PathPrefix": "arch/x86/" } Results: { "Output": "arch/x86/Kconfig=436=config SMP\n--\narch/x86/Kconfig-458-\narch/x86/Kconfig:459:config X86_X2APIC\narch/x86/Kconfig-460-\tbool \"x2APIC interrupt controller architecture support\"\n" }
43/2	2026/08/02 02:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 25857 output: 33 thoughts: 25 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Analyzing Potential CPU Error Handling Mechanisms Alright, let's zero in on this `X86_X2APIC` thing. My immediate thought is to consider its implications for inter-processor communication and interrupt delivery, especially in the context of error handling. Is this going to be the primary mechanism we're using for signaling errors? Or is it a secondary system? What are the implications for NUMA architectures and error propagation across different cores and sockets? I need to consider the overhead of this approach. Now, let's pivot to `X86_MCE`. This feels like the more likely candidate for our core hardware error reporting. My mind is already jumping to the specific machine check architecture registers and the flow of error information. I need to think about how this interacts with the OS's error handling routines. Is it going to be a simple notification, or will we have granular control over the response to different error types? What about error containment? And memory error correction capabilities? The specific MSRs and the structure of the error codes are top of mind. Need to quickly recall how this plays with other error models like parity and ECC.
44/2	2026/08/02 02:59	tool	grepper	0m Args: { "Expression": "config X86_MCE", "PathPrefix": "arch/x86/" } Results: { "Output": "arch/x86/Kconfig=1117=config X86_REROUTE_FOR_BROKEN_BOOT_IRQS\n--\narch/x86/Kconfig-1139-\narch/x86/Kconfig:1140:config X86_MCE\narch/x86/Kconfig-1141-\tbool \"Machine Check / overheating reporting\"\n--\narch/x86/Kconfig-1149-\narch/x86/Kconfig:1150:config X86_MCELOG_LEGACY\narch/x86/Kconfig-1151-\tbool \"Support for deprecated /dev/mcelog character device\"\n--\narch/x86/Kconfig-1157-\narch/x86/Kconfig:1158:config X86_MCE_INTEL\narch/x86/Kconfig-1159-\tdef_bool y\n--\narch/x86/Kconfig-1165-\narch/x86/Kconfig:1166:config X86_MCE_AMD\narch/x86/Kconfig-1167-\tdef_bool y\n--\narch/x86/Kconfig=1174=config X86_ANCIENT_MCE\n--\narch/x86/Kconfig-1181-\narch/x86/Kconfig:1182:config X86_MCE_THRESHOLD\narch/x86/Kconfig-1183-\tdepends on X86_MCE_AMD \|\| X86_MCE_INTEL\n--\narch/x86/Kconfig-1185-\narch/x86/Kconfig:1186:config X86_MCE_INJECT\narch/x86/Kconfig-1187-\tdepends on X86_MCE \u0026\u0026 X86_LOCAL_APIC \u0026\u0026 DEBUG_FS\n" }
45/2	2026/08/02 02:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 26663 output: 275 thoughts: 593 Thoughts: My Analysis of the `X86_MCE` Patch and Fuzzing Strategy Okay, so we're looking at a patch related to `X86_MCE` and specifically how KVM handles leaving System Management Mode (SMM) through the RSM instruction. The configs in play are `KVM_SMM`, `KVM_AMD_SEV`, `KVM_INTEL_TDX`, `INTEL_TDX_HOST`, `CRYPTO_DEV_SP_PSP`, `CRYPTO_DEV_CCP_DD`, `KVM_INTEL`, `KVM_AMD`, `AMD_IOMMU`, `CMA`, `X86_X2APIC`, and, of course, `X86_MCE`. The heart of the matter is the `emulator_leave_smm` function. This patch fixes a bug where invalid guest state isn't handled correctly when a guest exits SMM using RSM. The fix modifies `emulator_leave_smm` to check if the required emulation is unhandleable, and if so, returns `X86EMUL_UNHANDLEABLE`. The rest of the patch seems to be refactoring around this new check, moving some logic into `vcpu_needs_initialization` and `unhandleable_emulation_required`. My immediate thought is, "Where do we focus our fuzzing efforts?" The patch's core logic change happens in `emulator_leave_smm`, so that's the natural first target. I considered `vmx_unhandleable_emulation_required` as a possible focus symbol. However, it's called from both `emulator_leave_smm` and `kvm_x86_vcpu_pre_run`. If we focus on `emulator_leave_smm`, we'll inherently hit `vmx_unhandleable_emulation_required` anyway, making `emulator_leave_smm` a sufficient, and perhaps more direct, point of attack. Now, the crucial question: Is `emulator_leave_smm` reachable and testable from userspace? The answer is yes. It's called when emulating the RSM instruction, which is a 16-bit instruction (0x0F 0xAA) executable by the guest in SMM. The RSM instruction effectively handles the exit from SMM. Syzkaller can generate this instruction and execute it within the VM. To confirm, I double-checked, and found the `tools/testing/selftests/kvm/x86/vmx_invalid_nested_guest_state.c` test, which includes: ```c static u8 smi_handler[] = { 0xe4, ARBITRARY_IO_PORT, /* IN $ARBITRARY_IO_PORT, %al / 0x0f, 0xaa, / RSM */ }; ``` This test clearly demonstrates the reachability and functionality. Therefore, `emulator_leave_smm` is absolutely the correct focus symbol. Let's call `set-results`.
46/2	2026/08/02 03:00	tool	set-results	0m Args: { "EnableConfigs": [ "KVM_SMM", "KVM_AMD_SEV", "KVM_INTEL_TDX", "INTEL_TDX_HOST", "CRYPTO_DEV_SP_PSP", "CRYPTO_DEV_CCP_DD", "KVM_INTEL", "KVM_AMD", "AMD_IOMMU", "CMA", "X86_X2APIC", "X86_MCE" ], "FocusSymbols": [ "emulator_leave_smm" ], "Reasoning": "The patch fixes a bug where KVM does not properly handle invalid guest state when leaving System Management Mode (SMM) via the RSM instruction. It modifies `emulator_leave_smm` to check if unhandleable emulation is required, and if so, returns `X86EMUL_UNHANDLEABLE`. The rest of the patch refactors the `vcpu_pre_run` op into `vcpu_needs_initialization` and `unhandleable_emulation_required` to support this check. We should focus fuzzing on `emulator_leave_smm` to test this new logic.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "KVM_SMM", "KVM_AMD_SEV", "KVM_INTEL_TDX", "INTEL_TDX_HOST", "CRYPTO_DEV_SP_PSP", "CRYPTO_DEV_CCP_DD", "KVM_INTEL", "KVM_AMD", "AMD_IOMMU", "CMA", "X86_X2APIC", "X86_MCE" ], "FocusSymbols": [ "emulator_leave_smm" ], "Reasoning": "The patch fixes a bug where KVM does not properly handle invalid guest state when leaving System Management Mode (SMM) via the RSM instruction. It modifies `emulator_leave_smm` to check if unhandleable emulation is required, and if so, returns `X86EMUL_UNHANDLEABLE`. The rest of the patch refactors the `vcpu_pre_run` op into `vcpu_needs_initialization` and `unhandleable_emulation_required` to support this check. We should focus fuzzing on `emulator_leave_smm` to test this new logic.", "WorthFuzzing": true }

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Tool Calls Summary:
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