KVM: MMU: Fix rmap_write_protect() hugepage iteration bug

rmap_next() does not work correctly after rmap_remove(), as it expects
the rmap chains not to change during iteration.  Fix (for now) by restarting
iteration from the beginning.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ee3f53098f0c..9628091c574d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -640,6 +640,7 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
                         rmap_remove(kvm, spte);
                         --kvm->stat.lpages;
                         set_shadow_pte(spte, shadow_trap_nonpresent_pte);
+                        spte = NULL;
                         write_protected = 1;
                 }
                 spte = rmap_next(kvm, rmapp, spte);