linux-kernel - Re: [PATCH] KVM: x86/mmu: Exempt nested EPT page tables from !USER, CR0.WP=0 logic

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: <0ed1eec4-512a-4831-a9be-8ad8bd00fcf1@nutanix.com>
Date: Wed, 4 Jun 2025 16:57:31 +0100
From: Sergey Dyasli <sergey.dyasli@...anix.com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jon Kohler <jon@...anix.com>, Paolo Bonzini <pbonzini@...hat.com>
Subject: Re: [PATCH] KVM: x86/mmu: Exempt nested EPT page tables from !USER,
 CR0.WP=0 logic

On 03/06/2025 00:48, Sean Christopherson wrote:
> Exempt nested EPT shadow pages tables from the CR0.WP=0 handling of
> supervisor writes, as EPT doesn't have a U/S bit and isn't affected by
> CR0.WP (or CR4.SMEP in the exception to the exception).
> 
> Opportunistically refresh the comment to explain what KVM is doing, as
> the only record of why KVM shoves in WRITE and drops USER is buried in
> years-old changelogs.
> 
> Cc: Jon Kohler <jon@...anix.com>
> Cc: Sergey Dyasli <sergey.dyasli@...anix.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Thank you for the patch, LGTM.

Reviewed-by: Sergey Dyasli <sergey.dyasli@...anix.com>

Sergey