linux-kernel - Re: [PATCH v2 11/25] KVM: x86/mmu: remove kvm_calc_shadow_root_page_role

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Message-ID: <f9e7903a-72b6-5bd7-4795-6c568b98f09d@redhat.com>
Date:   Tue, 8 Mar 2022 18:50:22 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        dmatlack@...gle.com
Subject: Re: [PATCH v2 11/25] KVM: x86/mmu: remove
 kvm_calc_shadow_root_page_role_common

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);

Paolo