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From: Dario Faggioli <dfaggioli@suse.com>
To: linux-kernel@vger.kernel.org
Cc: Lorenzo Brescia <lorenzo.brescia@edu.unito.it>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org
Subject: Re: [PATCH] kvm: tracing: Fix unmatched kvm_entry and kvm_exit events
Date: Sat, 16 Jan 2021 02:25:57 +0100	[thread overview]
Message-ID: <0a32e141d8929f75025a0d9544a4552f2a916c5d.camel@suse.com> (raw)
In-Reply-To: <160873470698.11652.13483635328769030605.stgit@Wayrath>

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On Wed, 2020-12-23 at 14:45 +0000, Dario Faggioli wrote:
> From: Lorenzo Brescia <lorenzo.brescia@edu.unito.it>
> 
> On VMX, if we exit and then re-enter immediately without leaving
> the vmx_vcpu_run() function, the kvm_entry event is not logged.
> That means we will see one (or more) kvm_exit, without its (their)
> corresponding kvm_entry, as shown here:
> 
>  CPU-1979 [002] 89.871187: kvm_entry: vcpu 1
>  CPU-1979 [002] 89.871218: kvm_exit:  reason MSR_WRITE
>  CPU-1979 [002] 89.871259: kvm_exit:  reason MSR_WRITE
> 
> It also seems possible for a kvm_entry event to be logged, but then
> we leave vmx_vcpu_run() right away (if vmx->emulation_required is
> true). In this case, we will have a spurious kvm_entry event in the
> trace.
> 
Gentle ping... :-)

Thanks and Regards

-- 
Dario Faggioli, Ph.D
http://about.me/dario.faggioli
Virtualization Software Engineer
SUSE Labs, SUSE https://www.suse.com/
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  reply	other threads:[~2021-01-16  1:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-23 14:45 [PATCH] kvm: tracing: Fix unmatched kvm_entry and kvm_exit events Dario Faggioli
2021-01-16  1:25 ` Dario Faggioli [this message]
2021-01-18 18:20 ` Paolo Bonzini
2021-01-21 14:55 ` Paolo Bonzini

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