Re: [PATCH] KVM: X86: always reset st->preempted in record_steal_time()

[Wanpeng Li]

On Fri, 28 May 2021 at 14:11, Lai Jiangshan <jiangshanlai@xxxxxxxxx> wrote:
>
> From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> 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