Messages in this thread Patch in this message | | | From | Wanpeng Li <> | Subject | [PATCH v2 3/3] KVM: X86: Do not yield to self | Date | Fri, 9 Apr 2021 12:18:31 +0800 |
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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> --- v1 -> v2: * update comments
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 f08e9b4..ce9a1d2 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8231,6 +8231,10 @@ static void kvm_sched_yield(struct kvm_vcpu *vcpu, unsigned long dest_id) if (!target || !READ_ONCE(target->ready)) goto no_yield; + /* Ignore requests to yield to self */ + if (vcpu == target) + goto no_yield; + if (kvm_vcpu_yield_to(target) <= 0) goto no_yield; -- 2.7.4
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