linux-kernel - Re: [PATCH] KVM: SEV: Fix handling of EFER

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Message-ID: <ZXN-QUBpq1nADjUN@google.com>
Date:   Fri, 8 Dec 2023 12:36:17 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Michael Roth <michael.roth@....com>, kvm@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: SEV: Fix handling of EFER_LMA bit when SEV-ES is enabled

On Fri, Dec 08, 2023, Paolo Bonzini wrote:
> On Wed, Dec 6, 2023 at 4:28 PM Sean Christopherson <seanjc@...gle.com> wrote:
> > So my very strong preference is to first skip the kvm_is_valid_sregs() check
> 
> No, please don't. If you want to add a quirk that, when disabled,
> causes all guest state get/set ioctls to fail, go ahead. But invalid
> processor state remains invalid, and should be rejected, even when KVM
> won't consume it.

Ugh, true, KVM should still reject garbage.