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 (vcpu->vcpu_id == target->vcpu_id) + goto no_yield; + if (!READ_ONCE(target->ready)) goto no_yield; -- 2.7.4
