linux-kernel - Re: [PATCH] KVM: x86/mmu: Refresh CR0.WP prior to checking for emulated permission faults

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Message-ID: <168116555741.1037547.7553662106650689195.b4-ty@google.com>
Date:   Mon, 10 Apr 2023 16:30:17 -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,
        Mathias Krause <minipli@...ecurity.net>
Subject: Re: [PATCH] KVM: x86/mmu: Refresh CR0.WP prior to checking for
 emulated permission faults

On Tue, 04 Apr 2023 17:26:08 -0700, Sean Christopherson wrote:
> If CR0.WP may be guest-owned, i.e. TDP is enabled, refresh the MMU's
> snapshot of the guest's CR0.WP prior to checking for permission faults
> when emulating a guest memory access.  If the guest toggles only CR0.WP
> and triggers emulation of a supervisor write, e.g. when KVM is emulating
> UMIP, KVM may consume a stale CR0.WP, i.e. use stale protection bits
> metadata.
> 
> [...]

Applied to kvm-x86 misc, with a reworked changelog.

[1/1] KVM: x86/mmu: Refresh CR0.WP prior to checking for emulated permission faults
      https://github.com/kvm-x86/linux/commit/cf9f4c0eb169

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