On 10/05/2010 01:59 AM, Marcelo Tosatti wrote:
Yep, the drawback is the unnecessary write fault. What i have here is:
--- kvm.orig/virt/kvm/kvm_main.c
+++ kvm/virt/kvm/kvm_main.c
@@ -827,7 +827,7 @@ unsigned long gfn_to_hva(struct kvm *kvm
}
EXPORT_SYMBOL_GPL(gfn_to_hva);
-pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
+pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn, int *writable)
{
struct page *page[1];
unsigned long addr;
@@ -842,8 +842,16 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t
return page_to_pfn(bad_page);
}
+ *writable = 1;
npages = get_user_pages_fast(addr, 1, 1, page);
+ /* attempt to map read-only */
+ if (unlikely(npages != 1)) {
+ npages = get_user_pages_fast(addr, 1, 0, page);
+ if (npages == 1)
+ *writable = 0;
+ }
+
if (unlikely(npages != 1)) {
struct vm_area_struct *vma;
Can rebase and resend, if you'd like.
That will work for me but not for ksm. I guess it's good to get things
going, so please to post it.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
