diff mbox series

[v2,3/3] KVM: X86: Do not yield to self

Message ID 1617941911-5338-3-git-send-email-wanpengli@tencent.com (mailing list archive)
State New, archived
Headers show
Series [v2,1/3] x86/kvm: Don't bother __pv_cpu_mask when !CONFIG_SMP | expand

Commit Message

Wanpeng Li April 9, 2021, 4:18 a.m. UTC 
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 mbox series

Patch

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;