[PATCH 05/60] KVM: SVM: Inject MCEs when Restricted Injection is active
From: Jörg Rödel <joro@8bytes.org>
Date: 2026-06-08 14:43:14
Also in:
kvm, kvm-riscv, kvmarm, linux-mips, lkml, loongarch
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Melody Wang <redacted> When Restricted Injection is active, only #HV exceptions can be injected into the SEV-SNP guest. Detect that, and then follow the #HV doorbell communication from the GHCB specification to inject the MCEs. Co-developed-by: Thomas Lendacky <thomas.lendacky@amd.com> Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com> Signed-off-by: Melody Wang <redacted> Signed-off-by: Joerg Roedel <redacted> --- arch/x86/include/asm/kvm-x86-ops.h | 1 + arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/svm/sev.c | 16 ++++++++++++++-- arch/x86/kvm/svm/svm.c | 17 +++++++++++++++++ arch/x86/kvm/svm/svm.h | 2 ++ arch/x86/kvm/vmx/main.c | 10 ++++++++++ arch/x86/kvm/vmx/vmx.c | 5 +++++ arch/x86/kvm/vmx/x86_ops.h | 1 + arch/x86/kvm/x86.c | 7 +++++++ 9 files changed, 58 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 3776cf5382a2..c8bff1e9325e 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h@@ -79,6 +79,7 @@ KVM_X86_OP(inject_exception) KVM_X86_OP(cancel_injection) KVM_X86_OP(interrupt_allowed) KVM_X86_OP(nmi_allowed) +KVM_X86_OP_OPTIONAL(mce_allowed) KVM_X86_OP(get_nmi_mask) KVM_X86_OP(set_nmi_mask) KVM_X86_OP(enable_nmi_window)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f14009f25a3b..43c92f0ada1e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h@@ -1861,6 +1861,7 @@ struct kvm_x86_ops { void (*cancel_injection)(struct kvm_vcpu *vcpu); int (*interrupt_allowed)(struct kvm_vcpu *vcpu, bool for_injection); int (*nmi_allowed)(struct kvm_vcpu *vcpu, bool for_injection); + int (*mce_allowed)(struct kvm_vcpu *vcpu); bool (*get_nmi_mask)(struct kvm_vcpu *vcpu); void (*set_nmi_mask)(struct kvm_vcpu *vcpu, bool masked); /* Whether or not a virtual NMI is pending in hardware. */
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index b48745fad8c5..6d5d66563b0d 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c@@ -5430,6 +5430,8 @@ static void __sev_snp_inject(enum inject_type type, struct kvm_vcpu *vcpu) if (type == INJECT_NMI) hvdb->events.nmi = 1; + else if (type == INJECT_MCE) + hvdb->events.mce = 1; else hvdb->events.vector = vcpu->arch.interrupt.nr;
@@ -5445,6 +5447,11 @@ bool sev_snp_queue_exception(struct kvm_vcpu *vcpu) if (!sev_snp_is_rinj_active(vcpu)) return false; + if (vcpu->arch.exception.vector == MC_VECTOR) { + __sev_snp_inject(INJECT_MCE, vcpu); + return true; + } + /* * Restricted Injection is enabled, only #HV is supported. * If the vector is not HV_VECTOR, do not inject the exception,
@@ -5513,7 +5520,7 @@ void sev_snp_cancel_injection(struct kvm_vcpu *vcpu) /* * KVM only injects a single event each time (prepare_hv_injection), - * so when events.nmi is true, the vector will be zero + * so when events.nmi is true, the MCE and vector will be zero. */ if (hvdb->events.vector) svm->vmcb->control.event_inj |= hvdb->events.vector |
@@ -5522,6 +5529,9 @@ void sev_snp_cancel_injection(struct kvm_vcpu *vcpu) if (hvdb->events.nmi) svm->vmcb->control.event_inj |= SVM_EVTINJ_TYPE_NMI; + if (hvdb->events.mce) + svm->vmcb->control.event_inj |= MC_VECTOR | SVM_EVTINJ_TYPE_EXEPT; + hvdb->events.pending_events = 0; out:
@@ -5547,9 +5557,11 @@ bool sev_snp_blocked(enum inject_type type, struct kvm_vcpu *vcpu) if (!hvdb) return true; - /* Indicate NMIs and interrupts blocked based on guest acknowledgment */ + /* Indicate NMIs, MCEs and interrupts blocked based on guest acknowledgment */ if (type == INJECT_NMI) blocked = hvdb->events.nmi; + else if (type == INJECT_MCE) + blocked = hvdb->events.mce; else blocked = !!hvdb->events.vector;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 5255393986cc..295e02c17b9b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c@@ -4049,6 +4049,22 @@ static int svm_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection) return 1; } +bool svm_mce_blocked(struct kvm_vcpu *vcpu) +{ + if (sev_snp_is_rinj_active(vcpu)) + return sev_snp_blocked(INJECT_MCE, vcpu); + + return false; +} + +static int svm_mce_allowed(struct kvm_vcpu *vcpu) +{ + if (svm_mce_blocked(vcpu)) + return 0; + + return 1; +} + static void svm_enable_irq_window(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu);
@@ -5362,6 +5378,7 @@ struct kvm_x86_ops svm_x86_ops __initdata = { .cancel_injection = svm_cancel_injection, .interrupt_allowed = svm_interrupt_allowed, .nmi_allowed = svm_nmi_allowed, + .mce_allowed = svm_mce_allowed, .get_nmi_mask = svm_get_nmi_mask, .set_nmi_mask = svm_set_nmi_mask, .enable_nmi_window = svm_enable_nmi_window,
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index bb0e5bfdb9a6..7d27ed7099a8 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h@@ -58,6 +58,7 @@ extern struct kvm_x86_ops svm_x86_ops __initdata; enum inject_type { INJECT_IRQ, INJECT_NMI, + INJECT_MCE, }; /*
@@ -801,6 +802,7 @@ void svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4); void disable_nmi_singlestep(struct vcpu_svm *svm); bool svm_smi_blocked(struct kvm_vcpu *vcpu); bool svm_nmi_blocked(struct kvm_vcpu *vcpu); +bool svm_mce_blocked(struct kvm_vcpu *vcpu); bool svm_interrupt_blocked(struct kvm_vcpu *vcpu); void svm_set_gif(struct vcpu_svm *svm, bool value); int svm_invoke_exit_handler(struct kvm_vcpu *vcpu, u64 exit_code);
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index dbebddf648be..f9c4703dda54 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c@@ -812,6 +812,15 @@ static void vt_cancel_hv_timer(struct kvm_vcpu *vcpu) } #endif +static int vt_mce_allowed(struct kvm_vcpu *vcpu) +{ + if (is_td_vcpu(vcpu)) + return 0; + + return vmx_mce_allowed(vcpu); +} + + static void vt_setup_mce(struct kvm_vcpu *vcpu) { if (is_td_vcpu(vcpu))
@@ -945,6 +954,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { .cancel_injection = vt_op(cancel_injection), .interrupt_allowed = vt_op(interrupt_allowed), .nmi_allowed = vt_op(nmi_allowed), + .mce_allowed = vt_op(mce_allowed), .get_nmi_mask = vt_op(get_nmi_mask), .set_nmi_mask = vt_op(set_nmi_mask), .enable_nmi_window = vt_op(enable_nmi_window),
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b9103de01428..a82a4197d18a 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c@@ -5220,6 +5220,11 @@ int vmx_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection) return !vmx_interrupt_blocked(vcpu); } +int vmx_mce_allowed(struct kvm_vcpu *vcpu) +{ + return 1; +} + int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr) { void __user *ret;
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index d09abeac2b56..b75dfe7f039d 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h@@ -92,6 +92,7 @@ void vmx_inject_exception(struct kvm_vcpu *vcpu); void vmx_cancel_injection(struct kvm_vcpu *vcpu); int vmx_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection); int vmx_nmi_allowed(struct kvm_vcpu *vcpu, bool for_injection); +int vmx_mce_allowed(struct kvm_vcpu *vcpu); bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu); void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked); void vmx_enable_nmi_window(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0550359ed798..4b6b628efa21 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c@@ -10794,6 +10794,12 @@ static int kvm_check_and_inject_events(struct kvm_vcpu *vcpu, kvm_update_dr7(vcpu); } + if (vcpu->arch.exception.vector == MC_VECTOR) { + r = static_call(kvm_x86_mce_allowed)(vcpu); + if (!r) + goto out_except; + } + kvm_inject_exception(vcpu); vcpu->arch.exception.pending = false;
@@ -10801,6 +10807,7 @@ static int kvm_check_and_inject_events(struct kvm_vcpu *vcpu, can_inject = false; } +out_except: /* Don't inject interrupts if the user asked to avoid doing so */ if (vcpu->guest_debug & KVM_GUESTDBG_BLOCKIRQ)
--
2.53.0