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authorAndrea Arcangeli <andrea@qumranet.com>2008-07-25 16:32:03 +0200
committerAvi Kivity <avi@qumranet.com>2008-07-29 12:33:50 +0300
commit604b38ac0369bd50fcbb33344aa5553c071009f7 (patch)
tree149325ef8ddbeb607a19052bb807383a6aa7a549 /arch/x86/kvm
parenta1708ce8a362c4999f1201237ae7b77c4d13af82 (diff)
KVM: Allow browsing memslots with mmu_lock
This allows reading memslots with only the mmu_lock hold for mmu notifiers that runs in atomic context and with mmu_lock held. Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/x86.c21
1 files changed, 14 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9870ce42292..c7b01efe064 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3974,16 +3974,23 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
*/
if (!user_alloc) {
if (npages && !old.rmap) {
+ unsigned long userspace_addr;
+
down_write(&current->mm->mmap_sem);
- memslot->userspace_addr = do_mmap(NULL, 0,
- npages * PAGE_SIZE,
- PROT_READ | PROT_WRITE,
- MAP_SHARED | MAP_ANONYMOUS,
- 0);
+ userspace_addr = do_mmap(NULL, 0,
+ npages * PAGE_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_ANONYMOUS,
+ 0);
up_write(&current->mm->mmap_sem);
- if (IS_ERR((void *)memslot->userspace_addr))
- return PTR_ERR((void *)memslot->userspace_addr);
+ if (IS_ERR((void *)userspace_addr))
+ return PTR_ERR((void *)userspace_addr);
+
+ /* set userspace_addr atomically for kvm_hva_to_rmapp */
+ spin_lock(&kvm->mmu_lock);
+ memslot->userspace_addr = userspace_addr;
+ spin_unlock(&kvm->mmu_lock);
} else {
if (!old.user_alloc && old.rmap) {
int ret;