From: Sean Christopherson Date: Thu, 9 Jul 2026 20:49:31 +0000 (-0700) Subject: KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2de20fea620430da99f7326a7b02121d2aed3c02;p=linux KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests commit 42a39ad5d592aec87a70527a4e694f6210694482 upstream. Track the GPA of the guest-provided VMSA used after AP_CREATION events when running SNP guests, instead of simply tracking whether or not the vCPU is using a guest-provided VMSA. KVM needs to know the GPA of the VMSA that's actively being used so that it can react to MMU invalidation events, i.e. so that KVM can drop the VMSA if its backing guest_memfd page is punched out of existence. Opportunistically rename snp_vmsa_gpa to clarify that it tracks the pending VMSA GPA, whereas snp_guest_vmsa_gpa now tracks the in-use VMSA GPA. Note! Take care to track the GPA, not the GFN, as VALID_PAGE() won't behave correctly if an invalid GFN is converted to a GPA for checking. Note #2! Keep snp_has_guest_vmsa so that switching to a guest-provided VMSA is sticky, even if the guest-provided VMSA becomes invalid. No functional change intended. Cc: stable@vger.kernel.org # 6.12.x Reviewed-by: Michael Roth Link: https://patch.msgid.link/20260709204948.1988414-2-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 606fad42ee82c..b7596d7a29d32 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -4037,6 +4037,7 @@ static void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu) /* Clear use of the VMSA */ svm->vmcb->control.vmsa_pa = INVALID_PAGE; + svm->sev_es.snp_guest_vmsa_gpa = INVALID_PAGE; /* * When replacing the VMSA during SEV-SNP AP creation, @@ -4044,11 +4045,11 @@ static void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu) */ vmcb_mark_all_dirty(svm->vmcb); - if (!VALID_PAGE(svm->sev_es.snp_vmsa_gpa)) + if (!VALID_PAGE(svm->sev_es.snp_pending_vmsa_gpa)) return; - gfn = gpa_to_gfn(svm->sev_es.snp_vmsa_gpa); - svm->sev_es.snp_vmsa_gpa = INVALID_PAGE; + gfn = gpa_to_gfn(svm->sev_es.snp_pending_vmsa_gpa); + svm->sev_es.snp_pending_vmsa_gpa = INVALID_PAGE; slot = gfn_to_memslot(vcpu->kvm, gfn); if (!slot) @@ -4073,6 +4074,7 @@ static void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu) svm->sev_es.snp_has_guest_vmsa = true; /* Use the new VMSA */ + svm->sev_es.snp_guest_vmsa_gpa = gfn_to_gpa(gfn); svm->vmcb->control.vmsa_pa = pfn_to_hpa(pfn); /* Mark the vCPU as runnable */ @@ -4139,10 +4141,10 @@ static int sev_snp_ap_creation(struct vcpu_svm *svm) return -EINVAL; } - target_svm->sev_es.snp_vmsa_gpa = svm->vmcb->control.exit_info_2; + target_svm->sev_es.snp_pending_vmsa_gpa = svm->vmcb->control.exit_info_2; break; case SVM_VMGEXIT_AP_DESTROY: - target_svm->sev_es.snp_vmsa_gpa = INVALID_PAGE; + target_svm->sev_es.snp_pending_vmsa_gpa = INVALID_PAGE; break; default: vcpu_unimpl(vcpu, "vmgexit: invalid AP creation request [%#x] from guest\n", @@ -4731,6 +4733,8 @@ int sev_vcpu_create(struct kvm_vcpu *vcpu) return -ENOMEM; svm->sev_es.vmsa = page_address(vmsa_page); + svm->sev_es.snp_pending_vmsa_gpa = INVALID_PAGE; + svm->sev_es.snp_guest_vmsa_gpa = INVALID_PAGE; vcpu->arch.guest_tsc_protected = snp_is_secure_tsc_enabled(vcpu->kvm); diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index d06823ee0e755..ffaec038902c4 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -248,7 +248,8 @@ struct vcpu_sev_es_state { u64 ghcb_registered_gpa; struct mutex snp_vmsa_mutex; /* Used to handle concurrent updates of VMSA. */ - gpa_t snp_vmsa_gpa; + gpa_t snp_pending_vmsa_gpa; + gpa_t snp_guest_vmsa_gpa; bool snp_ap_waiting_for_reset; bool snp_has_guest_vmsa; };