While trying to get Hyper-V running, I realized that the interrupt injection
mechanisms that are in place right now are not 100% correct.
This patch makes nested SVM's interrupt injection behave more like on a
real machine.
v2 calls BUG_ON when svm_set_irq is called with GIF=0
Signed-off-by: Alexander Graf <agraf@xxxxxxx>
---
arch/x86/kvm/svm.c | 39 ++++++++++++++++++++++++---------------
1 files changed, 24 insertions(+), 15 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index fa2a710..5b14c9d 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1517,7 +1517,8 @@ static int nested_svm_vmexit_real(struct vcpu_svm *svm, void *arg1,
/* Kill any pending exceptions */
if (svm->vcpu.arch.exception.pending == true)
nsvm_printk("WARNING: Pending Exception\n");
- svm->vcpu.arch.exception.pending = false;
+ kvm_clear_exception_queue(&svm->vcpu);
+ kvm_clear_interrupt_queue(&svm->vcpu);
/* Restore selected save entries */
svm->vmcb->save.es = hsave->save.es;
@@ -1585,7 +1586,8 @@ static int nested_svm_vmrun(struct vcpu_svm *svm, void *arg1,
svm->nested_vmcb = svm->vmcb->save.rax;
/* Clear internal status */
- svm->vcpu.arch.exception.pending = false;
+ kvm_clear_exception_queue(&svm->vcpu);
+ kvm_clear_interrupt_queue(&svm->vcpu);
/* Save the old vmcb, so we don't need to pick what we save, but
can restore everything when a VMEXIT occurs */
@@ -2277,21 +2279,14 @@ static inline void svm_inject_irq(struct vcpu_svm *svm, int irq)
((/*control->int_vector >> 4*/ 0xf) << V_INTR_PRIO_SHIFT);
}
-static void svm_queue_irq(struct kvm_vcpu *vcpu, unsigned nr)
-{
- struct vcpu_svm *svm = to_svm(vcpu);
-
- svm->vmcb->control.event_inj = nr |
- SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR;
-}
-
static void svm_set_irq(struct kvm_vcpu *vcpu, int irq)
{
struct vcpu_svm *svm = to_svm(vcpu);
- nested_svm_intr(svm);
+ BUG_ON(!(svm->vcpu.arch.hflags & HF_GIF_MASK));
- svm_queue_irq(vcpu, irq);
+ svm->vmcb->control.event_inj = irq |
+ SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR;
}
static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
@@ -2319,13 +2314,25 @@ static int svm_interrupt_allowed(struct kvm_vcpu *vcpu)
struct vmcb *vmcb = svm->vmcb;
return (vmcb->save.rflags & X86_EFLAGS_IF) &&
!(vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) &&
- (svm->vcpu.arch.hflags & HF_GIF_MASK);
+ (svm->vcpu.arch.hflags & HF_GIF_MASK) &&
+ !is_nested(svm);
}
static void enable_irq_window(struct kvm_vcpu *vcpu)
{
- svm_set_vintr(to_svm(vcpu));
- svm_inject_irq(to_svm(vcpu), 0x0);
+ struct vcpu_svm *svm = to_svm(vcpu);
+ nsvm_printk("Trying to open IRQ window\n");
+
+ nested_svm_intr(svm);
+
+ /* In case GIF=0 we can't rely on the CPU to tell us when
+ * GIF becomes 1, because that's a separate STGI/VMRUN intercept.
+ * The next time we get that intercept, this function will be
+ * called again though and we'll get the vintr intercept. */
+ if (svm->vcpu.arch.hflags & HF_GIF_MASK) {
+ svm_set_vintr(svm);
+ svm_inject_irq(svm, 0x0);
+ }
}
static void enable_nmi_window(struct kvm_vcpu *vcpu)
@@ -2393,6 +2400,8 @@ static void svm_complete_interrupts(struct vcpu_svm *svm)
case SVM_EXITINTINFO_TYPE_EXEPT:
/* In case of software exception do not reinject an exception
vector, but re-execute and instruction instead */
+ if (is_nested(svm))
+ break;
if (vector == BP_VECTOR || vector == OF_VECTOR)
break;
if (exitintinfo & SVM_EXITINTINFO_VALID_ERR) {
--
1.6.0.2
--
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