On Tue, May 19, 2009 at 12:54:03PM +0200, Alexander Graf wrote:
> 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);
>
What about pending NMI here?
> /* 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);
>
And here.
> /* 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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--
Gleb.
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