From: Sean Christopherson <seanjc@google.com>
To: Kim Phillips <kim.phillips@amd.com>
Cc: kvm@vger.kernel.org, linux-coco@lists.linux.dev,
linux-kernel@vger.kernel.org, x86@kernel.org,
Tom Lendacky <thomas.lendacky@amd.com>,
Michael Roth <michael.roth@amd.com>,
Ashish Kalra <ashish.kalra@amd.com>,
"Nikunj A . Dadhania" <nikunj@amd.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2 2/2] KVM: SEV: Configure "ALLOWED_SEV_FEATURES" VMCB Field
Date: Thu, 22 Aug 2024 16:31:44 -0700 [thread overview]
Message-ID: <ZsfKYHFkWA-Rh23C@google.com> (raw)
In-Reply-To: <20240822221938.2192109-3-kim.phillips@amd.com>
On Thu, Aug 22, 2024, Kim Phillips wrote:
> AMD EPYC 5th generation processors have introduced a feature that allows
> the hypervisor to control the SEV_FEATURES that are set for, or by, a
> guest [1]. ALLOWED_SEV_FEATURES can be used by the hypervisor to enforce
> that SEV-ES and SEV-SNP guests cannot enable features that the
> hypervisor does not want to be enabled.
>
> When ALLOWED_SEV_FEATURES is enabled, a VMRUN will fail if any
> non-reserved bits are 1 in SEV_FEATURES but are 0 in
> ALLOWED_SEV_FEATURES.
This may need additional uAPI so that userspace can opt-in. Dunno. I hope guests
aren't abusing features, but IIUC, flipping this on has the potential to break
existing VMs, correct?
prev parent reply other threads:[~2024-08-22 23:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-22 22:19 [PATCH v2 0/2] KVM: SEV: Add support for the ALLOWED_SEV_FEATURES feature Kim Phillips
2024-08-22 22:19 ` [PATCH v2 1/2] x86/cpufeatures: Add "Allowed SEV Features" Feature Kim Phillips
2024-08-25 12:35 ` Thomas Gleixner
2024-08-22 22:19 ` [PATCH v2 2/2] KVM: SEV: Configure "ALLOWED_SEV_FEATURES" VMCB Field Kim Phillips
2024-08-22 23:31 ` Sean Christopherson [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZsfKYHFkWA-Rh23C@google.com \
--to=seanjc@google.com \
--cc=ashish.kalra@amd.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=kim.phillips@amd.com \
--cc=kvm@vger.kernel.org \
--cc=linux-coco@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=michael.roth@amd.com \
--cc=mingo@redhat.com \
--cc=nikunj@amd.com \
--cc=pbonzini@redhat.com \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.