[PATCH] KVM: dirty all pages in kvm_write_guest_cached()

Radim Krčmář
2015-04-07T20:35:34Z

We dirtied only one page because writes originally couldn't span more.
Use improved syntax for '>> PAGE_SHIFT' while at it.

Fixes: 8f964525a121 ("KVM: Allow cross page reads and writes from cached translations.")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
The function handles cross memslot writes in a different path.

I think we should dirty pages after partial writes too (r < len),
but it probably won't happen and I already started refactoring :)

virt/kvm/kvm_main.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index aadef264bed1..863df9dcab6f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1665,6 +1665,7 @@ int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
{
struct kvm_memslots *slots = kvm_memslots(kvm);
int r;
+ gfn_t gfn;

BUG_ON(len > ghc->len);

@@ -1680,7 +1681,10 @@ int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
r = __copy_to_user((void __user *)ghc->hva, data, len);
if (r)
return -EFAULT;
- mark_page_dirty_in_slot(kvm, ghc->memslot, ghc->gpa >> PAGE_SHIFT);
+
+ for (gfn = gpa_to_gfn(ghc->gpa);
+ gfn <= gpa_to_gfn(ghc->gpa + len - 1); gfn++)
+ mark_page_dirty_in_slot(kvm, ghc->memslot, gfn);

return 0;
}
--
2.3.4