linux-kernel - Re: [PATCH Part1 RFC v2 02/20] x86/sev: Save the negotiated GHCB version

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Message-ID: <ae227ce0-1ffe-aa54-4106-daaf423f376c@amd.com>
Date:   Wed, 12 May 2021 10:03:43 -0500
From:   Brijesh Singh <brijesh.singh@....com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     brijesh.singh@....com, x86@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        tglx@...utronix.de, jroedel@...e.de, thomas.lendacky@....com,
        pbonzini@...hat.com, mingo@...hat.com, dave.hansen@...el.com,
        rientjes@...gle.com, seanjc@...gle.com, peterz@...radead.org,
        hpa@...or.com, tony.luck@...el.com
Subject: Re: [PATCH Part1 RFC v2 02/20] x86/sev: Save the negotiated GHCB
 version


On 5/12/21 9:31 AM, Borislav Petkov wrote:
> On Wed, May 12, 2021 at 09:03:41AM -0500, Brijesh Singh wrote:
>> Version 2 of the spec adds bunch of NAEs, and several of them are
>> optional except the hyervisor features NAE. IMO, a guest should bump the
>> GHCB version only after it has implemented all the required NAEs from
>> the version 2. It may help during the git bisect of the guest kernel --
>> mainly when the hypervisor supports the higher version.
> Aha, so AFAICT, the version bump should happen in patch 3 which adds
> that HV features NAE - not in a separate one after that. The logic
> being, with the patch which adds the functionality needed, you mark the
> guest as supporting v2.

Sure, I will squash the patch 3 and 4 and will do the same for the
hypervisor series. thanks

-Brijesh