Commit 046ddeed authored by Wanpeng Li's avatar Wanpeng Li Committed by Paolo Bonzini

KVM: Check preempted_in_kernel for involuntary preemption

preempted_in_kernel is updated in preempt_notifier when involuntary preemption
ocurrs, it can be stale when the voluntarily preempted vCPUs are taken into
account by kvm_vcpu_on_spin() loop. This patch lets it just check preempted_in_kernel
for involuntary preemption.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent a48d06f9
......@@ -2508,7 +2508,8 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
continue;
if (swait_active(&vcpu->wq) && !kvm_arch_vcpu_runnable(vcpu))
continue;
if (yield_to_kernel_mode && !kvm_arch_vcpu_in_kernel(vcpu))
if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&
!kvm_arch_vcpu_in_kernel(vcpu))
continue;
if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
continue;
......@@ -4205,7 +4206,7 @@ static void kvm_sched_in(struct preempt_notifier *pn, int cpu)
{
struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
vcpu->preempted = false;
WRITE_ONCE(vcpu->preempted, false);
WRITE_ONCE(vcpu->ready, false);
kvm_arch_sched_in(vcpu, cpu);
......@@ -4219,7 +4220,7 @@ static void kvm_sched_out(struct preempt_notifier *pn,
struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
if (current->state == TASK_RUNNING) {
vcpu->preempted = true;
WRITE_ONCE(vcpu->preempted, true);
WRITE_ONCE(vcpu->ready, true);
}
kvm_arch_vcpu_put(vcpu);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment