From: Paolo Bonzini <pbonzini@redhat.com>
To: Steve Rutherford <srutherford@google.com>
Cc: Sean Christopherson <seanjc@google.com>,
LKML <linux-kernel@vger.kernel.org>,
KVM list <kvm@vger.kernel.org>, Joerg Roedel <joro@8bytes.org>,
Brijesh Singh <brijesh.singh@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Ashish Kalra <ashish.kalra@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Borislav Petkov <bp@suse.de>, X86 ML <x86@kernel.org>
Subject: Re: [PATCH v3 2/2] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall
Date: Tue, 4 May 2021 10:06:47 +0200 [thread overview]
Message-ID: <7c8f388c-1c0e-1fa8-24a5-46ffd40f8b24@redhat.com> (raw)
In-Reply-To: <CABayD+f41GQwCL1818S7iogNHO+MLesLJ-hCX5Bbf_0vFfDMrw@mail.gmail.com>
On 04/05/21 01:22, Steve Rutherford wrote:
> As far as I know, because of MSR filtering, the only "code" that needs
> to be in KVM for MSR handling is a #define reserving the PV feature
> number and a #define for the MSR number.
>
> Arguably, you don't even need to add the new PV bits to the supported
> cpuid, since MSR filtering is really what determines if kernel support
> is present.
Not only I don't need to do that, I must not. :)
>> At this point I very much prefer the latter, which is basically Ashish's
>> earlier patch.
>
> The minor distinction would be that if you expose the cpuid bit to the
> guest you plan on intercepting the MSR with filters, and would not
> need any handler code in the kernel.
Yep, and it's not a minor distinction after all (especially from the PoV
of the guy who actually ends up maintaining the code, i.e. me), so
that's what I'm going for.
Paolo
next prev parent reply other threads:[~2021-05-04 8:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-29 10:47 [PATCH v3 0/2] KVM: x86: guest interface for SEV live migration Paolo Bonzini
2021-04-29 10:47 ` [PATCH v3 1/2] KVM: x86: add MSR_KVM_MIGRATION_CONTROL Paolo Bonzini
2021-04-29 10:47 ` [PATCH v3 2/2] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall Paolo Bonzini
2021-04-30 20:10 ` Sean Christopherson
2021-05-01 9:01 ` Paolo Bonzini
2021-05-03 23:22 ` Steve Rutherford
2021-05-04 8:06 ` Paolo Bonzini [this message]
2021-05-04 17:09 ` Sean Christopherson
2021-05-04 20:27 ` Paolo Bonzini
2021-05-04 20:33 ` Sean Christopherson
2021-05-04 20:56 ` Paolo Bonzini
2021-05-04 21:16 ` Steve Rutherford
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