linux-kernel - Re: [PATCH v1 1/3] KVM: x86: Convert TDP level calculation to vendor's specific code

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: <YQxp6gg4W/pZsGuW@google.com>
Date:   Thu, 5 Aug 2021 22:44:58 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Jim Mattson <jmattson@...gle.com>
Cc:     Wei Huang <wei.huang2@....com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, pbonzini@...hat.com,
        vkuznets@...hat.com, wanpengli@...cent.com, joro@...tes.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org,
        hpa@...or.com
Subject: Re: [PATCH v1 1/3] KVM: x86: Convert TDP level calculation to
 vendor's specific code

On Thu, Aug 05, 2021, Jim Mattson wrote:
> On Thu, Aug 5, 2021 at 1:55 PM Wei Huang <wei.huang2@....com> wrote:
> >
> > This design assumes that all x86 CPUs have the flexibility of changing the
> > nested page table level different from host CPU.
> 
> I can't even parse this sentence. What are you trying to say here?

NPT inherits the host's CR4, and thus CR4.LA57.  So KVM NPT is stuck using whatever
N-level paging the host kernel is using.