Message ID | 20210527173358.49427-1-jiangshanlai@gmail.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | KVM: X86: always reset st->preempted in record_steal_time() | expand |
On Fri, 28 May 2021 at 14:11, Lai Jiangshan <jiangshanlai@gmail.com> wrote: > > From: Lai Jiangshan <laijs@linux.alibaba.com> > > st->preempted needs to be reset in record_steal_time() to clear the > KVM_VCPU_PREEMPTED bit. > > But the commit 66570e966dd9 ("kvm: x86: only provide PV features if > enabled in guest's CPUID") made it cleared conditionally and > KVM_VCPU_PREEMPTED might not be cleared when entering into the guest. > > Also make st->preempted be only read once, so that trace_kvm_pv_tlb_flush() > and kvm_vcpu_flush_tlb_guest() is consistent with same value of st->preempted. > > Cc: Oliver Upton <oupton@google.com> > Fixes: 66570e966dd9 ("kvm: x86: only provide PV features if enabled in guest's CPUID") It has already been fixed by commit 1eff0ada88b48 (KVM: X86: Fix vCPU preempted state from guest's point of view) in kvm/master. Wanpeng
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index bbc4e04e67ad..b8a7259ebd14 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3101,10 +3101,14 @@ static void record_steal_time(struct kvm_vcpu *vcpu) * expensive IPIs. */ if (guest_pv_has(vcpu, KVM_FEATURE_PV_TLB_FLUSH)) { + u8 st_preempted = xchg(&st->preempted, 0); + trace_kvm_pv_tlb_flush(vcpu->vcpu_id, - st->preempted & KVM_VCPU_FLUSH_TLB); - if (xchg(&st->preempted, 0) & KVM_VCPU_FLUSH_TLB) + st_preempted & KVM_VCPU_FLUSH_TLB); + if (st_preempted & KVM_VCPU_FLUSH_TLB) kvm_vcpu_flush_tlb_guest(vcpu); + } else { + st->preempted = 0; } vcpu->arch.st.preempted = 0;