Re: [PATCH 4/5] KVM: x86: MMU: Remove mapping_level_dirty_bitmap()

From: Paolo Bonzini
Date: Thu Oct 15 2015 - 11:35:39 EST




On 15/10/2015 12:43, Takuya Yoshikawa wrote:
> +static inline bool memslot_invalid(struct kvm_memory_slot *slot)

Can you make this function memslot_valid_for_gpte(struct kvm_memory_slot
*slot, bool no_dirty_log), and have it return

slot && !(slot->flags & KVM_MEMSLOT_INVALID) &&
(!no_dirty_log || !slot->dirty_bitmap)

? If gfn_to_memslot_dirty_bitmap and mapping_level call the same
function, it helps highlighting the similarity between them. Your
optimization loses that similarity in the name, but I think we can bring
it back somehow.

Otherwise, the patches are great. Thanks!

Paolo


> +{
> + if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
> + return true;
> +
> + return false;
> +}
> +
> static struct kvm_memory_slot *
> gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn,
> bool no_dirty_log)
> @@ -858,25 +866,22 @@ gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn,
> struct kvm_memory_slot *slot;
>
> slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
> - if (!slot || slot->flags & KVM_MEMSLOT_INVALID ||
> - (no_dirty_log && slot->dirty_bitmap))
> + if (memslot_invalid(slot) || (no_dirty_log && slot->dirty_bitmap))
> slot = NULL;
>
> return slot;
> }
>
> -static bool mapping_level_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t large_gfn)
> -{
> - return !gfn_to_memslot_dirty_bitmap(vcpu, large_gfn, true);
> -}
> -
> static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn,
> bool *force_pt_level)
> {
> int host_level, level, max_level;
> + struct kvm_memory_slot *slot;
> +
> + slot = kvm_vcpu_gfn_to_memslot(vcpu, large_gfn);
>
> if (likely(!*force_pt_level))
> - *force_pt_level = mapping_level_dirty_bitmap(vcpu, large_gfn);
> + *force_pt_level = memslot_invalid(slot) || slot->dirty_bitmap;
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