From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Thu, 10 Jul 2008 23:54:29 +0000 (-0300)
Subject: KVM: MMU: improve invalid shadow root page handling
X-Git-Tag: v2.6.27-rc1~968^2~3
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=376c53c2b30d4a1955240f59f4ecd959aa118f92;p=linux-2.6

KVM: MMU: improve invalid shadow root page handling

Harden kvm_mmu_zap_page() against invalid root pages that
had been shadowed from memslots that are gone.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ff7cf63217..7f57da6638 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -930,14 +930,17 @@ static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
 	}
 	kvm_mmu_page_unlink_children(kvm, sp);
 	if (!sp->root_count) {
-		if (!sp->role.metaphysical)
+		if (!sp->role.metaphysical && !sp->role.invalid)
 			unaccount_shadowed(kvm, sp->gfn);
 		hlist_del(&sp->hash_link);
 		kvm_mmu_free_page(kvm, sp);
 	} else {
+		int invalid = sp->role.invalid;
 		list_move(&sp->link, &kvm->arch.active_mmu_pages);
 		sp->role.invalid = 1;
 		kvm_reload_remote_mmus(kvm);
+		if (!sp->role.metaphysical && !invalid)
+			unaccount_shadowed(kvm, sp->gfn);
 	}
 	kvm_mmu_reset_last_pte_updated(kvm);
 }