linux-kernel - [PATCH 33/39] KVM: MMU: Add locking around kvm_mmu_slot_remove_write

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Date:	Thu, 25 Sep 2008 14:55:05 +0300
From:	Avi Kivity <avi@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	kvm@...r.kernel.org, Avi Kivity <avi@...ranet.com>
Subject: [PATCH 33/39] KVM: MMU: Add locking around kvm_mmu_slot_remove_write_access()

From: Avi Kivity <avi@...ranet.com>

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

Signed-off-by: Avi Kivity <avi@...ranet.com>
---
 arch/x86/kvm/mmu.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a24da8f..5052acd 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2097,6 +2097,7 @@ 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;
@@ -2110,6 +2111,7 @@ 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)
-- 
1.6.0.1

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