Messages in this thread | | | Date | Thu, 8 Apr 2021 16:56:22 +0000 | From | Sean Christopherson <> | Subject | Re: [PATCH] KVM: X86: Do not yield to self |
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On Thu, Apr 08, 2021, Wanpeng Li wrote: > From: Wanpeng Li <wanpengli@tencent.com> > > If the target is self we do not need to yield, we can avoid malicious > guest to play this. > > Signed-off-by: Wanpeng Li <wanpengli@tencent.com> > --- > Rebased on https://lore.kernel.org/kvm/1617697935-4158-1-git-send-email-wanpengli@tencent.com/ > > arch/x86/kvm/x86.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 43c9f9b..260650f 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -8230,6 +8230,10 @@ static void kvm_sched_yield(struct kvm_vcpu *vcpu, unsigned long dest_id) > if (!target) > goto no_yield; > > + /* yield to self */
If you're going to bother with a comment, maybe elaborate a bit, e.g.
/* Ignore requests to yield to self. */
> + if (vcpu->vcpu_id == target->vcpu_id) > + goto no_yield; > + > if (!READ_ONCE(target->ready)) > goto no_yield; > > -- > 2.7.4 >
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