linux-kernel - Re: [PATCH 2/3] KVM: x86: Harden against unexpected adjustments to kvm_cpu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aXhtlcLi+M1MUT3t@intel.com>
Date: Tue, 27 Jan 2026 15:47:33 +0800
From: Chao Gao <chao.gao@...el.com>
To: Sean Christopherson <seanjc@...gle.com>
CC: Paolo Bonzini <pbonzini@...hat.com>, <kvm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Mathias Krause <minipli@...ecurity.net>,
	"John Allen" <john.allen@....com>, Rick Edgecombe
	<rick.p.edgecombe@...el.com>, Binbin Wu <binbin.wu@...ux.intel.com>, Xiaoyao
 Li <xiaoyao.li@...el.com>, "Jim Mattson" <jmattson@...gle.com>
Subject: Re: [PATCH 2/3] KVM: x86: Harden against unexpected adjustments to
 kvm_cpu_caps

On Fri, Jan 23, 2026 at 02:15:41PM -0800, Sean Christopherson wrote:
>Add a flag to track when KVM is actively configuring its CPU caps, and
>WARN if a cap is set or cleared if KVM isn't in its configuration stage.
>Modifying CPU caps after {svm,vmx}_set_cpu_caps() can be fatal to KVM, as
>vendor setup code expects the CPU caps to be frozen at that point, e.g.
>will do additional configuration based on the caps.
>
>Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Reviewed-by: Chao Gao <chao.gao@...el.com>