From: Sean Christopherson Date: Fri, 22 May 2026 23:26:58 +0000 (-0700) Subject: KVM: x86: Tell ->inject_page_fault() whether or a fault came from hardware X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fe0b872d750023eda270cbc01c53ead52b1049d8;p=thirdparty%2Fkernel%2Flinux.git KVM: x86: Tell ->inject_page_fault() whether or a fault came from hardware When injecting a page fault (including nested TDP faults into L1), tell the injection routine whether or not the fault originated in hardware, i.e. if KVM is effectively forwarding a fault it intercept. For nested TDP fault injection, KVM needs to grab PAGE_WALK vs. GUEST_FINAL information from the VMCB/VMCS, _if_ the fault originated in hardware. Note, simply checking whether or not the original exit was due a #NPF or EPT Violation isn't sufficient/correct, as the fault being synthesized for L1 may or may not be the "same" fault that triggered a VM-Exit from L2. E.g. if access to emulated MMIO in L2 hits a !PRESENT fault (EPT Violation or #NPF), e.g. because MMIO caching is disabled or it's the first time the GPA has been accessed by L2, then KVM will enter the emulator. If emulating the MMIO instruction then hits a nested TDP fault, e.g. because L2 was accessing MMIO with a MOVSQ (memory-to-memory move), or because L1 has since unmapped the code stream, then the TDP fault synthesized to L1 will not be the same emulated fault the triggered the VM-Exit. No functional change intended (nothing uses the new param, yet...). Link: https://patch.msgid.link/20260522232701.3671446-3-seanjc@google.com Signed-off-by: Sean Christopherson --- diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 2b986a733cd6..29fec7c59a6f 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -484,7 +484,8 @@ struct kvm_mmu { u64 (*get_pdptr)(struct kvm_vcpu *vcpu, int index); int (*page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault); void (*inject_page_fault)(struct kvm_vcpu *vcpu, - struct x86_exception *fault); + struct x86_exception *fault, + bool from_hardware); gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, gpa_t gva_or_gpa, u64 access, struct x86_exception *exception); @@ -2304,9 +2305,18 @@ void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code); void kvm_queue_exception_p(struct kvm_vcpu *vcpu, unsigned nr, unsigned long payload); void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned int nr, bool has_error_code, u32 error_code); -void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault); -void kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, - struct x86_exception *fault); +void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault, + bool from_hardware); +void __kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, + struct x86_exception *fault, + bool from_hardware); + +static inline void kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, + struct x86_exception *fault) +{ + __kvm_inject_emulated_page_fault(vcpu, fault, false); +} + bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl); bool kvm_require_dr(struct kvm_vcpu *vcpu, int dr); diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 51f8b4522314..cc9c7deb34bc 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -813,7 +813,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault */ if (!r) { if (!fault->prefetch) - kvm_inject_emulated_page_fault(vcpu, &walker.fault); + __kvm_inject_emulated_page_fault(vcpu, &walker.fault, true); return RET_PF_RETRY; } diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 3d1fd1776e19..edb15f9c6403 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -34,7 +34,8 @@ #define CC KVM_NESTED_VMENTER_CONSISTENCY_CHECK static void nested_svm_inject_npf_exit(struct kvm_vcpu *vcpu, - struct x86_exception *fault) + struct x86_exception *fault, + bool from_hardware) { struct vcpu_svm *svm = to_svm(vcpu); struct vmcb *vmcb = svm->vmcb; diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 4690a4d23709..3bb7eaa7b2a5 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -411,7 +411,8 @@ static void nested_ept_invalidate_addr(struct kvm_vcpu *vcpu, gpa_t eptp, } static void nested_ept_inject_page_fault(struct kvm_vcpu *vcpu, - struct x86_exception *fault) + struct x86_exception *fault, + bool from_hardware) { struct vmcs12 *vmcs12 = get_vmcs12(vcpu); struct vcpu_vmx *vmx = to_vmx(vcpu); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9c52c11ba5f5..93958df30230 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -969,7 +969,8 @@ static int complete_emulated_insn_gp(struct kvm_vcpu *vcpu, int err) EMULTYPE_COMPLETE_USER_EXIT); } -void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) +void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault, + bool from_hardware) { ++vcpu->stat.pf_guest; @@ -986,8 +987,9 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) fault->address); } -void kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, - struct x86_exception *fault) +void __kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, + struct x86_exception *fault, + bool from_hardware) { struct kvm_mmu *fault_mmu; WARN_ON_ONCE(fault->vector != PF_VECTOR); @@ -1004,9 +1006,9 @@ void kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, kvm_mmu_invalidate_addr(vcpu, fault_mmu, fault->address, KVM_MMU_ROOT_CURRENT); - fault_mmu->inject_page_fault(vcpu, fault); + fault_mmu->inject_page_fault(vcpu, fault, from_hardware); } -EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_inject_emulated_page_fault); +EXPORT_SYMBOL_FOR_KVM_INTERNAL(__kvm_inject_emulated_page_fault); void kvm_inject_nmi(struct kvm_vcpu *vcpu) { @@ -14058,7 +14060,7 @@ bool kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu, fault.nested_page_fault = false; fault.address = work->arch.token; fault.async_page_fault = true; - kvm_inject_page_fault(vcpu, &fault); + kvm_inject_page_fault(vcpu, &fault, false); return true; } else { /* @@ -14229,7 +14231,7 @@ void kvm_fixup_and_inject_pf_error(struct kvm_vcpu *vcpu, gva_t gva, u16 error_c fault.address = gva; fault.async_page_fault = false; } - vcpu->arch.walk_mmu->inject_page_fault(vcpu, &fault); + vcpu->arch.walk_mmu->inject_page_fault(vcpu, &fault, true); } EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_fixup_and_inject_pf_error);