linux-kernel - Re: [PATCH 3/4] KVM: x86: SVM: use vmcb01 in avic_init

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Message-ID: <7b1999d1-4fd7-1b59-76f7-4287ad2c2a99@redhat.com>
Date:   Wed, 9 Mar 2022 16:48:56 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Maxim Levitsky <mlevitsk@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     kvm@...r.kernel.org, Jim Mattson <jmattson@...gle.com>,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Borislav Petkov <bp@...en8.de>, x86@...nel.org
Subject: Re: [PATCH 3/4] KVM: x86: SVM: use vmcb01 in avic_init_vmcb

On 3/1/22 18:25, Maxim Levitsky wrote:
>> I don't like this change.  It's not bad code, but it'll be confusing because it
>> implies that it's legal for svm->vmcb to be something other than svm->vmcb01.ptr
>> when this is called.
> Honestly I don't see how you had reached this conclusion.
>   
> I just think that code that always works on vmcb01
> should use it, even if it happens that vmcb == vmcb01.
>   
> If you insist I can drop this patch or add WARN_ON instead,
> I just think that this way is cleaner.
>   

I do like the patch, but you should do the same in init_vmcb() and 
svm_hv_init_vmcb() as well.

Paolo