linux-kernel - Re: [PATCH] KVM: x86: Allow, don't ignore, same-value writes to immutable MSRs

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Message-ID: <171465959389.758834.11674247619237178621.b4-ty@google.com>
Date: Fri,  3 May 2024 14:32:16 -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>, Raghavendra Rao Ananta <rananta@...gle.com>
Subject: Re: [PATCH] KVM: x86: Allow, don't ignore, same-value writes to
 immutable MSRs

On Mon, 08 Apr 2024 16:15:00 -0700, Sean Christopherson wrote:
> When handling userspace writes to immutable feature MSRs for a vCPU that
> has already run, fall through into the normal code to set the MSR instead
> of immediately returning '0'.  I.e. allow such writes, instead of ignoring
> such writes.  This fixes a bug where KVM incorrectly allows writes to the
> VMX MSRs that enumerate which CR{0,4} can be set, but only if the vCPU has
> already run.
> 
> [...]

Applied to kvm-x86 misc.

[1/1] KVM: x86: Allow, don't ignore, same-value writes to immutable MSRs
      https://github.com/kvm-x86/linux/commit/1d294dfaba8c

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