----- Original Message -----
> From: "Roman Kagan" <rkagan@xxxxxxxxxxxxx>
> To: "Radim Krčmář" <rkrcmar@xxxxxxxxxx>, "Paolo Bonzini" <pbonzini@xxxxxxxxxx>, kvm@xxxxxxxxxxxxxxx
> Cc: "Denis Lunev" <den@xxxxxxxxxxxxx>, "Roman Kagan" <rkagan@xxxxxxxxxxxxx>
> Sent: Friday, December 2, 2016 9:47:54 AM
> Subject: [PATCH 5/5] kvm/svm: kick L2 guest to L1 by ready async_pf
>
> When async pagefault is resolved vCPU may be executing L2 guest.
>
> In order to allow L1 take better scheduling decisions in such cases,
> make L2 exit to L1 on a fake external interupt, without actually
> injecting it (unless L2 has other reasons to vmexit).
>
> This patch does that for x86/AMD.
>
> Signed-off-by: Roman Kagan <rkagan@xxxxxxxxxxxxx>
> ---
> Note 1: I didn't have a chance to test this; I'll do when I get access to an
> AMD machine and let you know if anything goes wrong
>
> Note 2: I mostly modelled this patch after the one for vmx but is looks not
> very appealing for svm. I'd appreciate being pointed at a better location
> where to stick the fake external interrupt vmexit.
This should not be necessary, SVM has a different mechanism (which
requires L1 cooperation) to handle async page faults.
Paolo
>
> arch/x86/kvm/svm.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 8ca1eca..1f6ae15 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -3723,6 +3723,15 @@ static int mwait_interception(struct vcpu_svm *svm)
> return nop_interception(svm);
> }
>
> +static int svm_check_nested_events(struct kvm_vcpu *vcpu, bool
> external_intr)
> +{
> + struct vcpu_svm *svm = to_svm(vcpu);
> +
> + if (kvm_async_pf_has_ready(vcpu))
> + nested_svm_intr(svm);
> + return 0;
> +}
> +
> enum avic_ipi_failure_cause {
> AVIC_IPI_FAILURE_INVALID_INT_TYPE,
> AVIC_IPI_FAILURE_TARGET_NOT_RUNNING,
> @@ -5406,6 +5415,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init =
> {
>
> .check_intercept = svm_check_intercept,
> .handle_external_intr = svm_handle_external_intr,
> + .check_nested_events = svm_check_nested_events,
>
> .sched_in = svm_sched_in,
>
> --
> 2.9.3
>
>
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