1 files changed, 23 insertions, 10 deletions

diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index ca4260e3503..ba1a93f935c 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -59,6 +59,22 @@ static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
 	symbol_put(vfio_group_put_external_user);
 }
 
+static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
+{
+	long (*fn)(struct vfio_group *, unsigned long);
+	long ret;
+
+	fn = symbol_get(vfio_external_check_extension);
+	if (!fn)
+		return false;
+
+	ret = fn(vfio_group, VFIO_DMA_CC_IOMMU);
+
+	symbol_put(vfio_external_check_extension);
+
+	return ret > 0;
+}
+
 /*
  * Groups can use the same or different IOMMU domains.  If the same then
  * adding a new group may change the coherency of groups we've previously
@@ -75,13 +91,10 @@ static void kvm_vfio_update_coherency(struct kvm_device *dev)
 	mutex_lock(&kv->lock);
 
 	list_for_each_entry(kvg, &kv->group_list, node) {
-		/*
-		 * TODO: We need an interface to check the coherency of
-		 * the IOMMU domain this group is using.  For now, assume
-		 * it's always noncoherent.
-		 */
-		noncoherent = true;
-		break;
+		if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
+			noncoherent = true;
+			break;
+		}
 	}
 
 	if (noncoherent != kv->noncoherent) {
@@ -101,14 +114,14 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
 	struct kvm_vfio *kv = dev->private;
 	struct vfio_group *vfio_group;
 	struct kvm_vfio_group *kvg;
-	void __user *argp = (void __user *)arg;
+	int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
 	struct fd f;
 	int32_t fd;
 	int ret;
 
 	switch (attr) {
 	case KVM_DEV_VFIO_GROUP_ADD:
-		if (get_user(fd, (int32_t __user *)argp))
+		if (get_user(fd, argp))
 			return -EFAULT;
 
 		f = fdget(fd);
@@ -148,7 +161,7 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
 		return 0;
 
 	case KVM_DEV_VFIO_GROUP_DEL:
-		if (get_user(fd, (int32_t __user *)argp))
+		if (get_user(fd, argp))
 			return -EFAULT;
 
 		f = fdget(fd);