linux-kernel - Re: [PATCH 1/2] kvm/x86: Move MSR_K7

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Message-ID: <20190325183909.GQ12016@zn.tnic>
Date:   Mon, 25 Mar 2019 19:39:09 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     KVM <kvm@...r.kernel.org>, Joerg Roedel <joro@...tes.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Tony Luck <tony.luck@...el.com>,
        Yazen Ghannam <Yazen.Ghannam@....com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] kvm/x86: Move MSR_K7_HWCR to svm.c

On Mon, Mar 25, 2019 at 11:21:33AM -0700, Sean Christopherson wrote:
> Won't this prevent emulating an AMD guest on Intel hardware, e.g. due to
> injecting #GPs during boot?

I guess, but...

> Keeping support in kvm_{get,set}_msr_common
> doesn't preclude svm_{get,set}_msr() from having SVM-specific handling for
> the MSR.

... is kvm_{get,set}_msr_common() supposed to cover for all those
overlapping MSRs between AMD and Intel? svm_{get,set}_msr() have a lot
more AMD-specific MSRs just like vmx_{get,set}_msr() respectively for
Intel.

Which would mean that if you really want to support those cross-vendor
emulations, you don't need the svm* and vmx* MSR accessors... or am I
missing something?

-- 
Regards/Gruss,
    Boris.

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