On Thu, Apr 08, 2021, Wanpeng Li wrote: > From: Wanpeng Li <wanpengli@xxxxxxxxxxx> > > 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@xxxxxxxxxxx> > --- > Rebased on https://lore.kernel.org/kvm/1617697935-4158-1-git-send-email-wanpengli@xxxxxxxxxxx/ > > 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 >
