Merge branch 'kvm-updates-2.6.27' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm

* 'kvm-updates-2.6.27' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm:
  KVM: s390: Fix kvm on IBM System z10
  KVM: Advertise synchronized mmu support to userspace
  KVM: Synchronize guest physical memory map to host virtual memory map
  KVM: Allow browsing memslots with mmu_lock
  KVM: Allow reading aliases with mmu_lock

2 files changed, 25 insertions, 0 deletions

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 0ea064cbfbc8..69511f74f912 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -371,6 +371,7 @@ struct kvm_trace_rec {
 #define KVM_CAP_PV_MMU 13
 #define KVM_CAP_MP_STATE 14
 #define KVM_CAP_COALESCED_MMIO 15
+#define KVM_CAP_SYNC_MMU 16  /* Changes to host mmap are reflected in guest */
 
 /*
  * ioctls for VM fds
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 07d68a8ae8e9..8525afc53107 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -121,6 +121,12 @@ struct kvm {
         struct kvm_coalesced_mmio_dev *coalesced_mmio_dev;
         struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
 #endif
+
+#ifdef KVM_ARCH_WANT_MMU_NOTIFIER
+        struct mmu_notifier mmu_notifier;
+        unsigned long mmu_notifier_seq;
+        long mmu_notifier_count;
+#endif
 };
 
 /* The guest did something we don't support. */
@@ -332,4 +338,22 @@ int kvm_trace_ioctl(unsigned int ioctl, unsigned long arg)
 #define kvm_trace_cleanup() ((void)0)
 #endif
 
+#ifdef KVM_ARCH_WANT_MMU_NOTIFIER
+static inline int mmu_notifier_retry(struct kvm_vcpu *vcpu, unsigned long mmu_seq)
+{
+        if (unlikely(vcpu->kvm->mmu_notifier_count))
+                return 1;
+        /*
+         * Both reads happen under the mmu_lock and both values are
+         * modified under mmu_lock, so there's no need of smb_rmb()
+         * here in between, otherwise mmu_notifier_count should be
+         * read before mmu_notifier_seq, see
+         * mmu_notifier_invalidate_range_end write side.
+         */
+        if (vcpu->kvm->mmu_notifier_seq != mmu_seq)
+                return 1;
+        return 0;
+}
+#endif
+
 #endif