Re: [PART1 RFC v2 07/10] svm: Add VMEXIT handlers for AVIC

From: Suravee Suthikulpanit
Date: Thu Mar 17 2016 - 15:44:53 EST


On 3/10/16 03:55, Radim KrÄmÃÅ wrote:
2016-03-04 14:46-0600, Suravee Suthikulpanit:
>From: Suravee Suthikulpanit<suravee.suthikulpanit@xxxxxxx>
>Introduce VMEXIT handlers, avic_incp_ipi_interception() and
>Signed-off-by: Suravee Suthikulpanit<suravee.suthikulpanit@xxxxxxx>
>diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
>@@ -3690,6 +3690,264 @@ static int mwait_interception(struct vcpu_svm *svm)
>+ kvm_for_each_vcpu(i, vcpu, kvm) {
>+ if (!kvm_apic_match_dest(vcpu, apic,
>+ icrl & APIC_SHORT_MASK,
>+ icrl & APIC_DEST_MASK))
>+ continue;
>+ kvm_vcpu_kick(vcpu);
KVM shouldn't kick VCPUs that are running. (Imagine a broadcast when
most VCPUs are in guest mode.)

So, besides checking if the vcpu match the destination, I will add the check to see if the is_running bit is set before calling kvm_vcpu_kick()

I think a new helper might be useful here: we only want to wake up from
wait queue, but never force VCPU out of guest mode ... kvm_vcpu_kick()
does both.

If I only kick non-running vcpu, do I still need this new helper function?