Re: [PATCH 1/2] replace drop_interrupt_shadow by set_interrupt_shadow

Avi Kivity
2009-05-10T13:08:43Z

Glauber Costa wrote:
> This patch replaces drop_interrupt_shadow with the more
> general set_interrupt_shadow, that can either drop or raise
> it, depending on its parameter.
>
> void (*skip_emulated_instruction)(struct kvm_vcpu *vcpu);
> + void (*set_interrupt_shadow)(struct kvm_vcpu *vcpu, int mask);
> + u32 (*get_interrupt_shadow)(struct kvm_vcpu *vcpu);
>

Would be better to make these symmetric in their mask types.

> +++ b/arch/x86/kvm/svm.c
> @@ -202,6 +202,27 @@ static int is_external_interrupt(u32 info)
> return info == (SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR);
> }
>
> +static u32 svm_get_interrupt_shadow(struct kvm_vcpu *vcpu)
> +{
> + struct vcpu_svm *svm = to_svm(vcpu);
> + u32 ret = 0;
> +
> + if (svm->vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK)
> + ret |= (X86_SHADOW_INT_STI && X86_SHADOW_INT_MOV_SS);
>

&& -> |. Parentheses unnecessary.

> {
> struct vcpu_svm *svm = to_svm(vcpu);
> @@ -2637,6 +2652,8 @@ static struct kvm_x86_ops svm_x86_ops = {
> .run = svm_vcpu_run,
> .handle_exit = handle_exit,
> .skip_emulated_instruction = skip_emulated_instruction,
> + .set_interrupt_shadow= svm_set_interrupt_shadow,
>

Missing space.

> +static void vmx_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)
> +{
> + u32 interruptibility_old = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
> + u32 interruptibility = interruptibility_old;
> +
> + switch (mask) {
> + case 0:
> + interruptibility &= ~((GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS));
> + break;
>

Need to clear this unconditionally, otherwise 'sti; mov ss' will set
both flags.

> + case X86_SHADOW_INT_MOV_SS:
> + interruptibility |= GUEST_INTR_STATE_MOV_SS;
> + break;
> + case X86_SHADOW_INT_STI:
> + interruptibility |= GUEST_INTR_STATE_STI;
> + break;
> + default:
> + printk(KERN_ERR "Bogus mask for interrupt shadow!\n");
> + }
>

I suggest we deal with the case where both are set. One day we'll live
migrate this state, and if we come from an AMD host, we might get this
state.

--
error compiling committee.c: too many arguments to function