Re: [PATCH v2 4/6] KVM: x86/mmu: fast_page_fault support for the TDP MMU

[David Matlack <dmatlack@google.com>]

On Wed, Jun 30, 2021 at 09:48:00PM +0000, David Matlack wrote:
> Make fast_page_fault interoperate with the TDP MMU by leveraging
> walk_shadow_page_lockless_{begin,end} to acquire the RCU read lock and
> introducing a new helper function kvm_tdp_mmu_get_last_sptep_lockless to
> grab the lowest level sptep.
> 
> Suggested-by: Ben Gardon <bgardon@google.com>
> Signed-off-by: David Matlack <dmatlack@google.com>
> ---
>  arch/x86/kvm/mmu/mmu.c     | 55 +++++++++++++++++++++++++++-----------
>  arch/x86/kvm/mmu/tdp_mmu.c | 36 +++++++++++++++++++++++++
>  arch/x86/kvm/mmu/tdp_mmu.h |  2 ++
>  3 files changed, 78 insertions(+), 15 deletions(-)
> 

...

> +/*
> + * Must be called between kvm_tdp_mmu_walk_shadow_page_lockless_{begin,end}.
> + *
> + * The returned sptep must not be used after
> + * kvm_tdp_mmu_walk_shadow_page_lockless_end.
> + */

The function names in the comment are spelled wrong and should be:

   /*
    * Must be called between kvm_tdp_mmu_walk_lockless_{begin,end}.
    *
    * The returned sptep must not be used after kvm_tdp_mmu_walk_lockless_end.
    */