KVM: MMU: Switch to mmu spinlock

Convert the synchronization of the shadow handling to a separate mmu_lock
spinlock.

Also guard fetch() by mmap_sem in read-mode to protect against alias
and memslot changes.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index a020fb280540..2714068ee8bc 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -104,7 +104,8 @@ struct kvm_memory_slot {
 };
 
 struct kvm {
-        struct mutex lock; /* protects everything except vcpus */
+        struct mutex lock; /* protects the vcpus array and APIC accesses */
+        spinlock_t mmu_lock;
         struct mm_struct *mm; /* userspace tied to this vm */
         int nmemslots;
         struct kvm_memory_slot memslots[KVM_MEMORY_SLOTS +