linux-kernel - Re: [PATCH v2] KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on

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] [day] [month] [year] [list]

Date: Tue,  4 Jun 2024 16:29:19 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	Rik van Riel <riel@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>, Avi Kivity <avi@...hat.com>, 
	Breno Leitao <leitao@...ian.org>
Cc: rbc@...a.com, paulmck@...nel.org, stable@...r.kernel.org, 
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()

On Fri, 10 May 2024 02:23:52 -0700, Breno Leitao wrote:
> Use {READ,WRITE}_ONCE() to access kvm->last_boosted_vcpu to ensure the
> loads and stores are atomic.  In the extremely unlikely scenario the
> compiler tears the stores, it's theoretically possible for KVM to attempt
> to get a vCPU using an out-of-bounds index, e.g. if the write is split
> into multiple 8-bit stores, and is paired with a 32-bit load on a VM with
> 257 vCPUs:
> 
> [...]

Applied to kvm-x86 fixes, thanks!

[1/1] KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()
      https://github.com/kvm-x86/linux/commit/2b0844082557

--
https://github.com/kvm-x86/linux/tree/next