From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, dmatlack@google.com
Subject: Re: [PATCH v2 11/25] KVM: x86/mmu: remove kvm_calc_shadow_root_page_role_common
Date: Tue, 8 Mar 2022 18:17:30 +0000 [thread overview]
Message-ID: <Yiedukl6MC8OAAog@google.com> (raw)
In-Reply-To: <f9e7903a-72b6-5bd7-4795-6c568b98f09d@redhat.com>
On Tue, Mar 08, 2022, Paolo Bonzini wrote:
> On 3/8/22 18:48, Sean Christopherson wrote:
> > On Mon, Feb 21, 2022, Paolo Bonzini wrote:
> > > kvm_calc_shadow_root_page_role_common is the same as
> > > kvm_calc_cpu_mode except for the level, which is overwritten
> > > afterwards in kvm_calc_shadow_mmu_root_page_role
> > > and kvm_calc_shadow_npt_root_page_role.
> > >
> > > role.base.direct is already set correctly for the CPU mode,
> > > and CR0.PG=1 is required for VMRUN so it will also be
> > > correct for nested NPT.
> >
> > Bzzzt, this is wrong, the nested NPT MMU is indirect but will be computed as direct.
>
> CR0.PG=1 means it's *not* direct:
>
> > + role.base.direct = !____is_cr0_pg(regs);
Ha! I was just cleverly making the case for checking ____is_cr0_pg() instead of
"direct" for computing the dependent flags, I swear...
On a serious note, can we add a WARN_ON_ONCE(role.base.direct)? Not so much that
the WARN will be helpful, but to document the subtle dependency? If the relevant
code goes away in the end, ignore this requrest.
next prev parent reply other threads:[~2022-03-08 18:17 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-21 16:22 [PATCH v2 00/25] KVM MMU refactoring part 2: role changes Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 01/25] KVM: x86/mmu: avoid indirect call for get_cr3 Paolo Bonzini
2022-03-08 16:16 ` Sean Christopherson
2022-03-08 16:21 ` Paolo Bonzini
2022-03-08 16:32 ` Sean Christopherson
2022-03-08 16:43 ` Paolo Bonzini
2022-03-08 16:53 ` Sean Christopherson
2022-03-08 17:14 ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 02/25] KVM: x86/mmu: nested EPT cannot be used in SMM Paolo Bonzini
2022-03-08 16:18 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 03/25] KVM: x86/mmu: constify uses of struct kvm_mmu_role_regs Paolo Bonzini
2022-03-08 16:22 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 04/25] KVM: x86/mmu: pull computation of kvm_mmu_role_regs to kvm_init_mmu Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 05/25] KVM: x86/mmu: rephrase unclear comment Paolo Bonzini
2022-03-08 16:39 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 06/25] KVM: nVMX/nSVM: do not monkey-patch inject_page_fault callback Paolo Bonzini
2022-03-08 17:13 ` Sean Christopherson
2022-03-08 20:34 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 07/25] KVM: x86/mmu: remove "bool base_only" arguments Paolo Bonzini
2022-03-08 17:15 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 08/25] KVM: x86/mmu: split cpu_mode from mmu_role Paolo Bonzini
2022-03-08 17:36 ` Sean Christopherson
2022-03-08 17:49 ` Paolo Bonzini
2022-03-08 18:55 ` Sean Christopherson
2022-03-09 9:58 ` Paolo Bonzini
2022-03-09 15:38 ` Sean Christopherson
2022-03-09 15:40 ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 09/25] KVM: x86/mmu: do not recompute root level from kvm_mmu_role_regs Paolo Bonzini
2022-03-08 17:41 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 10/25] KVM: x86/mmu: remove ept_ad field Paolo Bonzini
2022-03-08 17:42 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 11/25] KVM: x86/mmu: remove kvm_calc_shadow_root_page_role_common Paolo Bonzini
2022-03-08 17:48 ` Sean Christopherson
2022-03-08 17:50 ` Paolo Bonzini
2022-03-08 18:17 ` Sean Christopherson [this message]
2022-03-08 18:18 ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 12/25] KVM: x86/mmu: cleanup computation of MMU roles for two-dimensional paging Paolo Bonzini
2022-03-08 18:11 ` Sean Christopherson
2022-03-08 18:24 ` Paolo Bonzini
2022-03-08 18:44 ` Sean Christopherson
2022-03-08 18:38 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 13/25] KVM: x86/mmu: cleanup computation of MMU roles for shadow paging Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 14/25] KVM: x86/mmu: store shadow EFER.NX in the MMU role Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 15/25] KVM: x86/mmu: remove extended bits from mmu_role, rename field Paolo Bonzini
2022-03-08 19:02 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 16/25] KVM: x86/mmu: rename kvm_mmu_role union Paolo Bonzini
2022-03-08 19:15 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 17/25] KVM: x86/mmu: remove redundant bits from extended role Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 18/25] KVM: x86/mmu: remove valid " Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 19/25] KVM: x86/mmu: simplify and/or inline computation of shadow MMU roles Paolo Bonzini
2022-03-08 19:35 ` Sean Christopherson
2022-03-08 19:41 ` Sean Christopherson
2022-03-09 10:33 ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 20/25] KVM: x86/mmu: pull CPU mode computation to kvm_init_mmu Paolo Bonzini
2022-03-08 19:45 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 21/25] KVM: x86/mmu: replace shadow_root_level with root_role.level Paolo Bonzini
2022-03-08 19:48 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 22/25] KVM: x86/mmu: replace root_level with cpu_mode.base.level Paolo Bonzini
2022-03-08 19:49 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 23/25] KVM: x86/mmu: replace direct_map with root_role.direct Paolo Bonzini
2022-03-08 19:52 ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 24/25] KVM: x86/mmu: initialize constant-value fields just once Paolo Bonzini
2022-03-08 20:58 ` Sean Christopherson
2022-03-09 10:34 ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 25/25] KVM: x86/mmu: extract initialization of the page walking data Paolo Bonzini
2022-03-08 20:02 ` Sean Christopherson
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