[PATCH v2 13/16] Add NMI injection support to SVM.

Gleb Natapov
2009-04-21T14:45:17Z

arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/svm.c | 50 +++++++++++++++++++++++++++++++++++++-
2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8b6f6e9..057a612 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -766,6 +766,7 @@ enum {
#define HF_GIF_MASK (1 << 0)
#define HF_HIF_MASK (1 << 1)
#define HF_VINTR_MASK (1 << 2)
+#define HF_NMI_MASK (1 << 3)

/*
* Hardware virtualization extension instructions may fault if a
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index c605477..3452bb4 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1834,6 +1834,14 @@ static int cpuid_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
return 1;
}

+static int iret_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
+{
+ ++svm->vcpu.stat.nmi_window_exits;
+ svm->vmcb->control.intercept &= ~(1UL << INTERCEPT_IRET);
+ svm->vcpu.arch.hflags &= ~HF_NMI_MASK;
+ return 1;
+}
+
static int invlpg_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
if (emulate_instruction(&svm->vcpu, kvm_run, 0, 0, 0) != EMULATE_DONE)
@@ -2111,6 +2119,7 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm,
[SVM_EXIT_VINTR] = interrupt_window_interception,
/* [SVM_EXIT_CR0_SEL_WRITE] = emulate_on_interception, */
[SVM_EXIT_CPUID] = cpuid_interception,
+ [SVM_EXIT_IRET] = iret_interception,
[SVM_EXIT_INVD] = emulate_on_interception,
[SVM_EXIT_HLT] = halt_interception,
[SVM_EXIT_INVLPG] = invlpg_interception,
@@ -2218,6 +2227,13 @@ static void pre_svm_run(struct vcpu_svm *svm)
new_asid(svm, svm_data);
}

+static void svm_inject_nmi(struct vcpu_svm *svm)
+{
+ svm->vmcb->control.event_inj = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_NMI;
+ vcpu->arch.hflags |= HF_NMI_MASK;
+ svm->vmcb->control.intercept |= (1UL << INTERCEPT_IRET);
+ ++vcpu->stat.nmi_injections;
+}

static inline void svm_inject_irq(struct vcpu_svm *svm, int irq)
{
@@ -2269,6 +2285,14 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu)
vmcb->control.intercept_cr_write |= INTERCEPT_CR8_MASK;
}

+static int svm_nmi_allowed(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+ struct vmcb *vmcb = svm->vmcb;
+ return !(vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) &&
+ !(svm->vcpu.arch.hflags & HF_NMI_MASK);
+}
+
static int svm_interrupt_allowed(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -2284,16 +2308,35 @@ static void enable_irq_window(struct kvm_vcpu *vcpu)
svm_inject_irq(to_svm(vcpu), 0x0);
}

+static void enable_nmi_window(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+
+ if (svm->vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK)
+ enable_irq_window(vcpu);
+}
+
static void svm_intr_inject(struct kvm_vcpu *vcpu)
{
/* try to reinject previous events if any */
+ if (vcpu->arch.nmi_injected) {
+ svm_inject_nmi(to_svm(vcpu));
+ return;
+ }
+
if (vcpu->arch.interrupt.pending) {
svm_queue_irq(to_svm(vcpu), vcpu->arch.interrupt.nr);
return;
}

/* try to inject new event if pending */
- if (kvm_cpu_has_interrupt(vcpu)) {
+ if (vcpu->arch.nmi_pending) {
+ if (svm_nmi_allowed(vcpu)) {
+ vcpu->arch.nmi_pending = false;
+ vcpu->arch.nmi_injected = true;
+ svm_inject_nmi(vcpu);
+ }
+ } else if (kvm_cpu_has_interrupt(vcpu)) {
if (svm_interrupt_allowed(vcpu)) {
kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu));
svm_queue_irq(to_svm(vcpu), vcpu->arch.interrupt.nr);
@@ -2312,7 +2355,10 @@ static void svm_intr_assist(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)

svm_intr_inject(vcpu);

- if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
+ /* enable NMI/IRQ window open exits if needed */
+ if (vcpu->arch.nmi_pending)
+ enable_nmi_window(vcpu);
+ else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
enable_irq_window(vcpu);

out:
--
1.5.6.5