From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Sun, 8 Jun 2008 04:48:53 +0000 (-0300)
Subject: KVM: MMU: Fix rmap_write_protect() hugepage iteration bug
X-Git-Tag: v2.6.26-rc8~3^2~9
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6597ca09e6c0e5aec7ffd2b8ab48c671d3c28414;p=linux-2.6

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>
---

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ee3f53098f..9628091c57 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);