From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] KVM: x86/mmu: Calculate and check "full" mmu_role for nested MMU
Date: Fri, 11 Jun 2021 16:45:31 +0000 [thread overview]
Message-ID: <YMOTK7eYytpw58Vc@google.com> (raw)
In-Reply-To: <b2084f55-3ce5-57c4-f580-d6a2de6ce612@redhat.com>
On Fri, Jun 11, 2021, Paolo Bonzini wrote:
> On 11/06/21 00:00, Sean Christopherson wrote:
> > things like the number of levels in the guest's page tables are
> > surprisingly important when walking the guest page tables
>
> Along which path though? I would have naively expected those to be driven
> only by the context->root_level.
The functional code is driven by context->root_level, but if KVM doesn't include
the level in the mmu_role then it will fail to update context->root_level when
L2 changes from 32-bit PAE to 64-bit. If all the CR0/CR4/EFER bits remain the
same, only the level will differ. Without this patch, role.level is always '0'
for the nested MMU.
next prev parent reply other threads:[~2021-06-11 16:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 22:00 [PATCH] KVM: x86/mmu: Calculate and check "full" mmu_role for nested MMU Sean Christopherson
2021-06-11 8:57 ` Vitaly Kuznetsov
2021-06-11 14:22 ` Sean Christopherson
2021-06-11 19:51 ` Sean Christopherson
2021-06-11 16:02 ` Paolo Bonzini
2021-06-11 16:19 ` Paolo Bonzini
2021-06-11 16:45 ` Sean Christopherson [this message]
2021-06-11 16:49 ` Paolo Bonzini
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