From: Avi Kivity <avi@qumranet.com>
Date: Thu, 6 Aug 2009 17:39:46 +0000 (-0300)
Subject: KVM: MMU: Add locking around kvm_mmu_slot_remove_write_access()
X-Git-Tag: v2.6.27.32~39
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=c832f513b1ebe93e0a2c71a98f319da4ce560f7f;p=karo-tx-linux.git

KVM: MMU: Add locking around kvm_mmu_slot_remove_write_access()

(cherry picked from commit 2245a28fe2e6fdb1bdabc4dcde1ea3a5c37e2a9e)

It was generally safe due to slots_lock being held for write, but it wasn't
very nice.

Signed-off-by: Avi Kivity <avi@qumranet.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 3da2508eb22a..32aa0b814842 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2055,6 +2055,7 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
 {
 	struct kvm_mmu_page *sp;
 
+	spin_lock(&kvm->mmu_lock);
 	list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
 		int i;
 		u64 *pt;
@@ -2068,6 +2069,7 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
 			if (pt[i] & PT_WRITABLE_MASK)
 				pt[i] &= ~PT_WRITABLE_MASK;
 	}
+	spin_unlock(&kvm->mmu_lock);
 }
 
 void kvm_mmu_zap_all(struct kvm *kvm)