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>
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index f73de63..f51e684 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -504,12 +504,12 @@
static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
struct kvm_assigned_pci_dev *assigned_dev)
{
- int r = 0;
+ int r = 0, idx;
struct kvm_assigned_dev_kernel *match;
struct pci_dev *dev;
mutex_lock(&kvm->lock);
- down_read(&kvm->slots_lock);
+ idx = srcu_read_lock(&kvm->srcu);
match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
assigned_dev->assigned_dev_id);
@@ -573,7 +573,7 @@
}
out:
- up_read(&kvm->slots_lock);
+ srcu_read_unlock(&kvm->srcu, idx);
mutex_unlock(&kvm->lock);
return r;
out_list_del:
@@ -585,7 +585,7 @@
pci_dev_put(dev);
out_free:
kfree(match);
- up_read(&kvm->slots_lock);
+ srcu_read_unlock(&kvm->srcu, idx);
mutex_unlock(&kvm->lock);
return r;
}