KVM: MMU: fix mmu notifier invalidate handler for huge spte

commit 6e3e243c3b6e0bbd18c6ce0fbc12bc3fe2d77b34 upstream.

The index wasn't calculated correctly (off by one) for huge spte so KVM guest
was unstable with transparent hugepages.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b1ed0a1..92b6ca4 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -799,8 +799,12 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
                        ret = handler(kvm, &memslot->rmap[gfn_offset], data);
 
                        for (j = 0; j < KVM_NR_PAGE_SIZES - 1; ++j) {
-                               int idx = gfn_offset;
-                               idx /= KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL + j);
+                               unsigned long idx;
+                               int nr;
+
+                               nr = KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL+j);
+                               idx = (memslot->base_gfn+gfn_offset) / nr -
+                                       memslot->base_gfn / nr;
                                ret |= handler(kvm,
                                        &memslot->lpage_info[j][idx].rmap_pde,
                                        data);