From: Sean Christopherson <seanjc@google.com>
To: Yosry Ahmed <yosry@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v3 1/2] KVM: x86: Check EFER validity on KVM_SET_SREGS*
Date: Wed, 22 Jul 2026 13:45:58 -0700 [thread overview]
Message-ID: <amEsBpHgIM_H7lDm@google.com> (raw)
In-Reply-To: <CAO9r8zPhmLNdVgyXib-P+Ge_KSp=a8gA3mLDcpjJ5br-eXpj8w@mail.gmail.com>
On Mon, Jul 13, 2026, Yosry Ahmed wrote:
> On Mon, Jul 13, 2026 at 11:02 AM Yosry Ahmed <yosry@kernel.org> wrote:
> >
> > When handling userspace SREGS writes, check the validity of EFER (i.e.
> > allowed bits) before writing the new value of EFER through the
> > per-vendor set_efer callbacks. This prevents userspace from writing
> > bogus values (e.g. EFER.SVME=1 with nested=0).
> >
> > Note: on KVM_SET_MSRS, KVM only checks EFER validity in terms of KVM
> > caps, not guest caps, so it is possible to set EFER bits that are
> > supported by KVM but not by the guest CPUID. Potentially allowing
> > userspace to set msrs before CPUID.
> >
> > However, for KVM_SET_SREGS*, check the validity of the set bits against
> > both KVM and guest caps. This is consistent with other validity checks
> > (e.g. for CR4) that check validity against guest caps, which already
> > imposes the need to set CPUID before SREGS.
> >
> > Cc: stable@vger.kernel.org
> > Change-Id: I45701ec440e4fdd8f086eb70db0c0845fb0ed509
>
> Forgot to drop these, sorry :/
By "these", I assume you mean the Change-Id here and in the next patch? But keep
the Cc: stable@?
next prev parent reply other threads:[~2026-07-22 20:46 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-13 18:01 [PATCH v3 0/2] KVM: x86: Fix missing EFER validity checks Yosry Ahmed
2026-07-13 18:01 ` [PATCH v3 1/2] KVM: x86: Check EFER validity on KVM_SET_SREGS* Yosry Ahmed
2026-07-13 18:09 ` Yosry Ahmed
2026-07-22 20:45 ` Sean Christopherson [this message]
2026-07-22 20:47 ` Yosry Ahmed
2026-07-13 18:14 ` sashiko-bot
2026-07-13 18:54 ` Yosry Ahmed
2026-07-29 4:53 ` Jim Mattson
2026-07-29 16:52 ` Yosry Ahmed
2026-07-29 18:14 ` Yosry Ahmed
2026-07-29 20:48 ` Sean Christopherson
2026-07-13 18:01 ` [PATCH v3 2/2] KVM: selftests: Extend set_sregs test to cover EFER Yosry Ahmed
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=amEsBpHgIM_H7lDm@google.com \
--to=seanjc@google.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=stable@vger.kernel.org \
--cc=yosry@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).