Re: [RFC PATCH v3 06/19] KVM: x86: mmu: add gfn_in_memslot helper

Sean Christopherson
2022-05-19T16:44:04Z

On Wed, Apr 27, 2022, Maxim Levitsky wrote:
> This is a tiny refactoring, and can be useful to check
> if a GPA/GFN is within a memslot a bit more cleanly.

This doesn't explain the actual motivation, which is to use the new helper from
arch code.

> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
> include/linux/kvm_host.h | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 252ee4a61b58b..12e261559070b 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -1580,6 +1580,13 @@ int kvm_request_irq_source_id(struct kvm *kvm);
> void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id);
> bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args);
>
> +
> +static inline bool gfn_in_memslot(struct kvm_memory_slot *slot, gfn_t gfn)
> +{
> + return (gfn >= slot->base_gfn && gfn < slot->base_gfn + slot->npages);
> +}
> +

Spurious newline.

> +
> /*
> * Returns a pointer to the memslot if it contains gfn.
> * Otherwise returns NULL.
> @@ -1590,12 +1597,13 @@ try_get_memslot(struct kvm_memory_slot *slot, gfn_t gfn)
> if (!slot)
> return NULL;
>
> - if (gfn >= slot->base_gfn && gfn < slot->base_gfn + slot->npages)
> + if (gfn_in_memslot(slot, gfn))
> return slot;
> else
> return NULL;

At this point, maybe:

if (!slot || !gfn_in_memslot(slot, gfn))
return NULL;

return slot;

> }
>
> +
> /*
> * Returns a pointer to the memslot that contains gfn. Otherwise returns NULL.
> *
> --
> 2.26.3
>