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SubjectRe: [PATCH 02/13] KVM: reuse memslot in kvm_write_guest_page
Date
Paolo Bonzini <pbonzini@redhat.com> writes:

> From: Radim Krčmář <rkrcmar@redhat.com>
>
> Saves one O(log N) search.

It really doesn't hurt to change this to:
"Caching memslot value helps us avoid another O(log N) search
later when calling mark_page_dirty_in_slot()."

Sorry I am not a fan of commit messages less than 75 characters :)
Or you can also call me dumb :)

> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> Message-Id: <1428695247-27603-1-git-send-email-rkrcmar@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> virt/kvm/kvm_main.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 90977418aeb6..b6d415156283 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1590,15 +1590,17 @@ int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data,
> int offset, int len)
> {
> int r;
> + struct kvm_memory_slot *memslot;
> unsigned long addr;
>
> - addr = gfn_to_hva(kvm, gfn);
> + memslot = gfn_to_memslot(kvm, gfn);
> + addr = gfn_to_hva_memslot(memslot, gfn);
> if (kvm_is_error_hva(addr))
> return -EFAULT;
> r = __copy_to_user((void __user *)addr + offset, data, len);
> if (r)
> return -EFAULT;
> - mark_page_dirty(kvm, gfn);
> + mark_page_dirty_in_slot(kvm, memslot, gfn);
> return 0;
> }
> EXPORT_SYMBOL_GPL(kvm_write_guest_page);


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