From: Sean Christopherson <seanjc@google.com>
To: Like Xu <like.xu.linux@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] KVM: x86/intr: Explicitly check NMI from guest to eliminate false positives
Date: Mon, 4 Dec 2023 07:55:45 -0800 [thread overview]
Message-ID: <ZW32geNb18p9ibrR@google.com> (raw)
In-Reply-To: <20231204074535.9567-1-likexu@tencent.com>
On Mon, Dec 04, 2023, Like Xu wrote:
> From: Like Xu <likexu@tencent.com>
>
> Explicitly checking the source of external interrupt is indeed NMI and not
> other types in the kvm_arch_pmi_in_guest(), which prevents perf-kvm false
> positive samples generated after vm-exit but before kvm_before_interrupt()
> from being incorrectly labelled as guest samples:
...
> Fixes: 73cd107b9685 ("KVM: x86: Drop current_vcpu for kvm_running_vcpu + kvm_arch_vcpu variable")
The behavior is deliberate, and was added by commit dd60d217062f ("KVM: x86: Fix
perf timer mode IP reporting"). *If* we want to undo that, then the best "fix"
would be to effective reverting that commit by dropping the IRQ usage of
kvm_before_interrupt() and renaming the helpers kvm_{before,after}_nmi(). But
my understanding is that the behavior is necessary for select PMU usage.
next prev parent reply other threads:[~2023-12-04 15:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-04 7:45 [PATCH] KVM: x86/intr: Explicitly check NMI from guest to eliminate false positives Like Xu
2023-12-04 15:55 ` Sean Christopherson [this message]
2023-12-05 6:23 ` Like Xu
2023-12-06 0:09 ` Sean Christopherson
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