linux-kernel - Re: [PATCH v2 4/4] KVM: x86: add new nested vmexit tracepoints

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Message-ID: <7d6bdd4fca0dfdd6528e416510877c3bfd0cbfac.camel@redhat.com>
Date:   Thu, 28 Sep 2023 13:42:06 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org
Cc:     Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH v2 4/4] KVM: x86: add new nested vmexit tracepoints

On, 2023-09-26 у 18:50 +0200, Paolo Bonzini writes:
> On 9/24/23 14:44, Maxim Levitsky wrote:
> > +		trace_kvm_nested_page_fault(fault->address,
> > +				vcpu->arch.ept_fault_error_code,
> 
> Any reason to include vcpu->arch.ept_fault_error_code rather than the 
> injected exit qualification?


The vcpu->arch.ept_fault_error_code is the original exit qualification
which I want to trace as the host error code
captured on ept fault to a new field, but I see new that I can use vmx_get_exit_qual()
to retrieve it again, thus avoiding the overhead.

Also for the injected error code I can use the 'exit_qualification' instead, I think
that I intended to so so but forgot to update the patch.

So something like that works fine for me:

		trace_kvm_nested_page_fault(fault->address,
				vmx_get_exit_qual(vcpu),
				exit_qualification);




Best regards,
	Maxim Levitsky

> 
> Paolo
> 
> > +				fault->error_code);