From: Sean Christopherson <seanjc@google.com>
To: Sasha Levin <sashal@kernel.org>
Cc: stable@vger.kernel.org, Yosry Ahmed <yosry@kernel.org>
Subject: Re: [PATCH 6.12.y] KVM: x86: Disallow EFER.LME and EFER.LMA if long mode is not supported
Date: Fri, 11 Sep 2026 07:22:38 -0700 [thread overview]
Message-ID: <aqQOroJmp1a3n-0W@google.com> (raw)
In-Reply-To: <20260911120502.489632-1-sashal@kernel.org>
On Fri, Sep 11, 2026, Sasha Levin wrote:
> From: Yosry Ahmed <yosry@kernel.org>
>
> [ Upstream commit e62392bf39ebfdf60d1d082799397fe1cbf8dfc5 ]
>
> Remove EFER.LME and EFER.LMA from EFER reserved bits only if long mode
> is actually supported. KVM does check long-mode support before allowing
> the bits for guest writes and userspace writes through KVM_SET_SREGS*
> (in __kvm_valid_efer()), but userspace writes through KVM_SET_MSRS only
> check reserved bits.
>
> In practice, this doesn't really matter. The true motiviation is getting
> rid of the #ifdeffery when initializing efer_reserved_bits.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Yosry Ahmed <yosry@kernel.org>
> Link: https://patch.msgid.link/20260713181020.2735367-3-yosry@kernel.org
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> [ adapted EFER changes to x86.c, placing the capability check in kvm_x86_vendor_init() because kvm_setup_efer_caps() is absent. ]
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
Acked-by: Sean Christopherson <seanjc@google.com>
prev parent reply other threads:[~2026-09-11 14:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-09 10:32 FAILED: patch "[PATCH] KVM: x86: Disallow EFER.LME and EFER.LMA if long mode is not" failed to apply to 6.12-stable tree gregkh
2026-09-11 12:05 ` [PATCH 6.12.y] KVM: x86: Disallow EFER.LME and EFER.LMA if long mode is not supported Sasha Levin
2026-09-11 14:22 ` 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=aqQOroJmp1a3n-0W@google.com \
--to=seanjc@google.com \
--cc=sashal@kernel.org \
--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 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.