From: Sean Christopherson <seanjc@google.com>
To: Yosry Ahmed <yosry@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Stefan Teodorescu <fane@google.com>
Subject: Re: [PATCH 2/4] KVM: x86/mmu: Bug the VM if KVM attempts to walk more levels than the MMU has
Date: Thu, 27 Aug 2026 06:48:17 -0700 [thread overview]
Message-ID: <apBAIVaHkqI_H50o@google.com> (raw)
In-Reply-To: <CAO9r8zMA-E7UYzNDT=0rn7sv7+=Ydxy2zzikMPV1_YarH9sOeg@mail.gmail.com>
On Thu, Aug 27, 2026, Yosry Ahmed wrote:
> On Wed, Aug 26, 2026 at 2:18 PM Sean Christopherson <seanjc@google.com> wrote:
> >
> > Extend the "EFER.LMA && !CR4.PAE" check, which exists largely to guard
> > against KVM configuring a paging32 MMU with more than 2 levels of paging,
>
> Is there value in keeping the original check? I suppose yes as you
> said it exists "largely" for this, but it would probably be nice to
> spell it out (if we know).
Because LMA && !PAE is still an illegal combination. The symptom we know about
is a misconfiguration of base.level vs. the paging template, but I also want to
guard against any other symptoms that stem from the bad state.
next prev parent reply other threads:[~2026-08-27 13:48 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-26 21:18 [PATCH 0/4] KVM: nSVM: Disallow bad L1 EFER for KVM_SET_NESTED_STATE Sean Christopherson
2026-08-26 21:18 ` [PATCH 1/4] KVM: nSVM: Reject KVM_SET_NESTED_STATE if L1 has EFER.LMA=1 && EFER.LME=0 Sean Christopherson
2026-08-26 21:33 ` sashiko-bot
2026-08-27 7:02 ` Yosry Ahmed
2026-08-27 13:36 ` Sean Christopherson
2026-08-27 16:29 ` Yosry Ahmed
2026-08-27 17:33 ` Sean Christopherson
2026-08-27 17:55 ` Yosry Ahmed
2026-08-27 18:24 ` Sean Christopherson
2026-08-27 21:41 ` Paolo Bonzini
2026-08-27 22:01 ` Yosry Ahmed
2026-08-28 5:26 ` Paolo Bonzini
2026-08-26 21:18 ` [PATCH 2/4] KVM: x86/mmu: Bug the VM if KVM attempts to walk more levels than the MMU has Sean Christopherson
2026-08-26 21:41 ` sashiko-bot
2026-08-26 21:56 ` Sean Christopherson
2026-08-27 7:05 ` Yosry Ahmed
2026-08-27 13:48 ` Sean Christopherson [this message]
2026-08-26 21:18 ` [PATCH 3/4] KVM: x86/mmu: Bug the VM if KVM calcs a CPU role with EFER.LMA=1 && CR4.PAE=0 Sean Christopherson
2026-08-26 21:31 ` sashiko-bot
2026-08-27 7:08 ` Yosry Ahmed
2026-08-27 14:57 ` Sean Christopherson
2026-08-27 16:38 ` Yosry Ahmed
2026-08-27 17:29 ` Sean Christopherson
2026-08-27 17:48 ` Yosry Ahmed
2026-08-27 18:13 ` Sean Christopherson
2026-08-26 21:18 ` [PATCH 4/4] KVM: x86/mmu: Convert MMU walker's bounds check from BUG_ON() to KVM_BUG_ON() Sean Christopherson
2026-08-27 7:11 ` Yosry Ahmed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=apBAIVaHkqI_H50o@google.com \
--to=seanjc@google.com \
--cc=fane@google.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=yosry@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox