linux-kernel - Re: [PATCH] KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O

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]

Message-ID: <175564471845.3066581.8347761517352370906.b4-ty@google.com>
Date: Tue, 19 Aug 2025 16:12:03 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Jim Mattson <jmattson@...gle.com>
Subject: Re: [PATCH] KVM: x86: Don't (re)check L1 intercepts when completing
 userspace I/O

On Tue, 15 Jul 2025 12:06:38 -0700, Sean Christopherson wrote:
> When completing emulation of instruction that generated a userspace exit
> for I/O, don't recheck L1 intercepts as KVM has already finished that
> phase of instruction execution, i.e. has already committed to allowing L2
> to perform I/O.  If L1 (or host userspace) modifies the I/O permission
> bitmaps during the exit to userspace,  KVM will treat the access as being
> intercepted despite already having emulated the I/O access.
> 
> [...]

Applied to kvm-x86 misc, thanks!

[1/1] KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O
      https://github.com/kvm-x86/linux/commit/e750f8539128

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