[PATCH] KVM: reuse memslot in kvm_write_guest_page

[PATCH] KVM: reuse memslot in kvm_write_guest_page

[Radim Krčmář]

Saves one O(log N) search.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 I'm still not sure how to bridge the gap between the code we have and
 the code I want, but all routes so far contained this change.  Notice
 that we use '_memslot' and '_in_slot' suffix for the same meaning ...
 (And the completely useless 'kvm' parameter for page dirtying.)

 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 91a36e21c0fb..09cf409b0389 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1589,15 +1589,17 @@ 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);
-- 
2.3.5

Re: [PATCH] KVM: reuse memslot in kvm_write_guest_page

[Paolo Bonzini]

On 10/04/2015 21:47, Radim Krčmář wrote:
> Saves one O(log N) search.
> 
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> ---
>  I'm still not sure how to bridge the gap between the code we have and
>  the code I want, but all routes so far contained this change.  Notice
>  that we use '_memslot' and '_in_slot' suffix for the same meaning ...
>  (And the completely useless 'kvm' parameter for page dirtying.)

I have the same patch (plus exporting mark_dirty_page_in_slot and
removing the extra 'kvm' parameter :)) in my SMM queue.  I'll replace it
with yours.

Paolo