KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update

Use two steps for memslot deletion: mark the slot invalid (which stops
instantiation of new shadow pages for that slot, but allows destruction),
then instantiate the new empty slot.

Also simplifies kvm_handle_hva locking.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 0757c7027986..b2e4d16dd39e 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1382,7 +1382,7 @@ static void kvm_release_vm_pages(struct kvm *kvm)
         int i, j;
         unsigned long base_gfn;
 
-        slots = kvm->memslots;
+        slots = rcu_dereference(kvm->memslots);
         for (i = 0; i < slots->nmemslots; i++) {
                 memslot = &slots->memslots[i];
                 base_gfn = memslot->base_gfn;
@@ -1837,6 +1837,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
         struct kvm_memory_slot *memslot;
         int is_dirty = 0;
 
+        down_write(&kvm->slots_lock);
         spin_lock(&kvm->arch.dirty_log_lock);
 
         r = kvm_ia64_sync_dirty_log(kvm, log);
@@ -1856,6 +1857,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
         }
         r = 0;
 out:
+        up_write(&kvm->slots_lock);
         spin_unlock(&kvm->arch.dirty_log_lock);
         return r;
 }