Re: [PATCH 10/12] KVM: MMU: load new PGD after the shadow MMU is initialized

Paolo Bonzini
2022-02-11T17:48:02Z

On 2/11/22 18:45, Sean Christopherson wrote:
> On Wed, Feb 09, 2022, Paolo Bonzini wrote:
>> Now that __kvm_mmu_new_pgd does not look at the MMU's root_level and
>> shadow_root_level anymore, pull the PGD load after the initialization of
>> the shadow MMUs.
>>
>> Besides being more intuitive, this enables future simplifications
>> and optimizations because it's not necessary anymore to compute the
>> role outside kvm_init_mmu. In particular, kvm_mmu_reset_context was not
>> attempting to use a cached PGD to avoid having to figure out the new role.
>> It will soon be able to follow what nested_{vmx,svm}_load_cr3 are doing,
>> and avoid unloading all the cached roots.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>
> If you add a sanity check as described in the other thread[*],
>
> Reviewed-by: Sean Christopherson <seanjc@google.com>

It's not as easy as I thought, but it becomes almost trivial with the
CPU/MMU role refactoring. I'll get that posted as soon as I can push a
final-ish version of this one to kvm/queue.

Paolo