commit e663ee64aefc57f7eff7325142206c4ea0200be8
author Avi Kivity <avi@qumranet.com> Thu May 31 15:46:04 2007 +0300
committer Avi Kivity <avi@qumranet.com> Mon Jul 16 12:05:44 2007 +0300
tree a95c5a1015914ee4101c1770039ad1457e8767c3
parent 0d551bb698e1328f685ae3611c4a4a96f41bef97

KVM: MMU: Make setting shadow ptes atomic on i386

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

drivers/kvm/mmu.c

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 3cdbf68..f24b540 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -22,6 +22,7 @@
 #include <linux/mm.h>
 #include <linux/highmem.h>
 #include <linux/module.h>
+#include <asm/cmpxchg.h>
 
 #include "vmx.h"
 #include "kvm.h"
@@ -204,6 +205,15 @@
 		== (PT_WRITABLE_MASK | PT_PRESENT_MASK);
 }
 
+static void set_shadow_pte(u64 *sptep, u64 spte)
+{
+#ifdef CONFIG_X86_64
+	set_64bit((unsigned long *)sptep, spte);
+#else
+	set_64bit((unsigned long long *)sptep, spte);
+#endif
+}
+
 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
 				  struct kmem_cache *base_cache, int min,
 				  gfp_t gfp_flags)
@@ -446,7 +456,7 @@
 		rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
 		rmap_remove(vcpu, spte);
 		kvm_arch_ops->tlb_flush(vcpu);
-		*spte &= ~(u64)PT_WRITABLE_MASK;
+		set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
 	}
 }
 
@@ -699,7 +709,7 @@
 		}
 		BUG_ON(!parent_pte);
 		kvm_mmu_put_page(vcpu, page, parent_pte);
-		*parent_pte = 0;
+		set_shadow_pte(parent_pte, 0);
 	}
 	kvm_mmu_page_unlink_children(vcpu, page);
 	if (!page->root_count) {