From: Tom Lendacky <thomas.lendacky@amd.com>
To: Borislav Petkov <bp@alien8.de>, Kim Phillips <kim.phillips@amd.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-coco@lists.linux.dev, x86@kernel.org,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
K Prateek Nayak <kprateek.nayak@amd.com>,
Nikunj A Dadhania <nikunj@amd.com>,
Michael Roth <michael.roth@amd.com>,
Naveen Rao <naveen.rao@amd.com>,
David Kaplan <david.kaplan@amd.com>,
stable@kernel.org
Subject: Re: [PATCH 1/2] KVM: SEV: IBPB-on-Entry guest support
Date: Fri, 30 Jan 2026 08:56:07 -0600 [thread overview]
Message-ID: <2295adbc-835f-4a84-934b-b7aba65137a8@amd.com> (raw)
In-Reply-To: <20260130123252.GAaXyk9DJEAiQeDyeh@fat_crate.local>
On 1/30/26 06:32, Borislav Petkov wrote:
> On Thu, Jan 29, 2026 at 04:32:49PM -0600, Kim Phillips wrote:
>> Not *all* SNP features are implemented in all guest kernel versions, and,
>> well, for those that don't require explicit guest code support, perhaps it's
>> because they aren't necessarily well defined and validated in all hardware
>> versions...
>
> Ok, can you add *this* feature to SNP_FEATURES_PRESENT? If not, why not?
It can be added. Any of the features added to SNP_FEATURES_PRESENT that
aren't set in the SNP_FEATURES_IMPL_REQ bitmap are really a no-op. The
SNP_FEATURES_PRESENT bitmap is meant to contain whatever bits are set in
SNP_FEATURES_IMPL_REQ when an implementation has been implemented for the
guest.
But, yeah, we could add all the bits that aren't set in
SNP_FEATURES_IMPL_REQ to SNP_FEATURES_PRESENT if it makes it clearer.
If we do that, it should probably be a separate patch (?) that also
rewords the comment above SNP_FEATURES_PRESENT
Thanks,
Tom
>
next prev parent reply other threads:[~2026-01-30 14:56 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-26 22:42 [PATCH 0/2] KVM: SEV: Add support for IBPB-on-Entry Kim Phillips
2026-01-26 22:42 ` [PATCH 1/2] KVM: SEV: IBPB-on-Entry guest support Kim Phillips
2026-01-27 6:19 ` Nikunj A. Dadhania
2026-01-28 19:02 ` Tom Lendacky
2026-01-28 19:23 ` Borislav Petkov
2026-01-29 0:38 ` Kim Phillips
2026-01-29 10:51 ` Borislav Petkov
2026-01-29 22:32 ` Kim Phillips
2026-01-30 12:32 ` Borislav Petkov
2026-01-30 14:56 ` Tom Lendacky [this message]
2026-01-30 15:45 ` Borislav Petkov
2026-02-02 15:38 ` Tom Lendacky
2026-02-02 15:49 ` Borislav Petkov
2026-02-02 16:09 ` Tom Lendacky
2026-02-02 17:12 ` Borislav Petkov
2026-01-26 22:42 ` [PATCH 2/2] KVM: SEV: Add support for IBPB-on-Entry Kim Phillips
2026-01-27 6:38 ` Nikunj A. Dadhania
2026-01-27 20:56 ` Kim Phillips
2026-01-28 19:08 ` Tom Lendacky
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