vhost: factor out IOTLB

This patch factors out IOTLB into a dedicated module in order to be reused by other modules like vringh. User may choose to enable the automatic retiring by specifying VHOST_IOTLB_FLAG_RETIRE flag to fit for the case of vhost device IOTLB implementation. Signed-off-by: Jason Wang <jasowang@redhat.com> Link: https://lore.kernel.org/r/20200326140125.19794-4-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-03-26 22:01:19 +08:00
parent 792a4f2ed2
commit 0bbe30668d
8 changed files with 315 additions and 181 deletions
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -50,10 +50,6 @@ enum {
 #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])

-INTERVAL_TREE_DEFINE(struct vhost_umem_node,
-		     rb, __u64, __subtree_last,
-		     START, LAST, static inline, vhost_umem_interval_tree);
-
 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
 {
@@ -584,21 +580,25 @@ err_mm:
 }
 EXPORT_SYMBOL_GPL(vhost_dev_set_owner);

-struct vhost_umem *vhost_dev_reset_owner_prepare(void)
+static struct vhost_iotlb *iotlb_alloc(void)
 {
-	return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL);
+	return vhost_iotlb_alloc(max_iotlb_entries,
+				 VHOST_IOTLB_FLAG_RETIRE);
+}
+
+struct vhost_iotlb *vhost_dev_reset_owner_prepare(void)
+{
+	return iotlb_alloc();
 }
 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);

 /* Caller should have device mutex */
-void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem)
+void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *umem)
 {
 	int i;

 	vhost_dev_cleanup(dev);

-	/* Restore memory to default empty mapping. */
-	INIT_LIST_HEAD(&umem->umem_list);
 	dev->umem = umem;
 	/* We don't need VQ locks below since vhost_dev_cleanup makes sure
 	 * VQs aren't running.
@@ -621,28 +621,6 @@ void vhost_dev_stop(struct vhost_dev *dev)
 }
 EXPORT_SYMBOL_GPL(vhost_dev_stop);

-static void vhost_umem_free(struct vhost_umem *umem,
-			    struct vhost_umem_node *node)
-{
-	vhost_umem_interval_tree_remove(node, &umem->umem_tree);
-	list_del(&node->link);
-	kfree(node);
-	umem->numem--;
-}
-
-static void vhost_umem_clean(struct vhost_umem *umem)
-{
-	struct vhost_umem_node *node, *tmp;
-
-	if (!umem)
-		return;
-
-	list_for_each_entry_safe(node, tmp, &umem->umem_list, link)
-		vhost_umem_free(umem, node);
-
-	kvfree(umem);
-}
-
 static void vhost_clear_msg(struct vhost_dev *dev)
 {
 	struct vhost_msg_node *node, *n;
@@ -680,9 +658,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
 		eventfd_ctx_put(dev->log_ctx);
 	dev->log_ctx = NULL;
 	/* No one will access memory at this point */
-	vhost_umem_clean(dev->umem);
+	vhost_iotlb_free(dev->umem);
 	dev->umem = NULL;
-	vhost_umem_clean(dev->iotlb);
+	vhost_iotlb_free(dev->iotlb);
 	dev->iotlb = NULL;
 	vhost_clear_msg(dev);
 	wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
@@ -718,27 +696,26 @@ static bool vhost_overflow(u64 uaddr, u64 size)
 }

 /* Caller should have vq mutex and device mutex. */
-static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,
+static bool vq_memory_access_ok(void __user *log_base, struct vhost_iotlb *umem,
 				int log_all)
 {
-	struct vhost_umem_node *node;
+	struct vhost_iotlb_map *map;

 	if (!umem)
 		return false;

-	list_for_each_entry(node, &umem->umem_list, link) {
-		unsigned long a = node->userspace_addr;
+	list_for_each_entry(map, &umem->list, link) {
+		unsigned long a = map->addr;

-		if (vhost_overflow(node->userspace_addr, node->size))
+		if (vhost_overflow(map->addr, map->size))
 			return false;


-		if (!access_ok((void __user *)a,
-				    node->size))
+		if (!access_ok((void __user *)a, map->size))
 			return false;
 		else if (log_all && !log_access_ok(log_base,
-						   node->start,
-						   node->size))
+						   map->start,
+						   map->size))
 			return false;
 	}
 	return true;
@@ -748,17 +725,17 @@ static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
 					       u64 addr, unsigned int size,
 					       int type)
 {
-	const struct vhost_umem_node *node = vq->meta_iotlb[type];
+	const struct vhost_iotlb_map *map = vq->meta_iotlb[type];

-	if (!node)
+	if (!map)
 		return NULL;

-	return (void *)(uintptr_t)(node->userspace_addr + addr - node->start);
+	return (void *)(uintptr_t)(map->addr + addr - map->start);
 }

 /* Can we switch to this memory table? */
 /* Caller should have device mutex but not vq mutex */
-static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,
+static bool memory_access_ok(struct vhost_dev *d, struct vhost_iotlb *umem,
 			     int log_all)
 {
 	int i;
@@ -1023,47 +1000,6 @@ static inline int vhost_get_desc(struct vhost_virtqueue *vq,
 	return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc));
 }

-static int vhost_new_umem_range(struct vhost_umem *umem,
-				u64 start, u64 size, u64 end,
-				u64 userspace_addr, int perm)
-{
-	struct vhost_umem_node *tmp, *node;
-
-	if (!size)
-		return -EFAULT;
-
-	node = kmalloc(sizeof(*node), GFP_ATOMIC);
-	if (!node)
-		return -ENOMEM;
-
-	if (umem->numem == max_iotlb_entries) {
-		tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link);
-		vhost_umem_free(umem, tmp);
-	}
-
-	node->start = start;
-	node->size = size;
-	node->last = end;
-	node->userspace_addr = userspace_addr;
-	node->perm = perm;
-	INIT_LIST_HEAD(&node->link);
-	list_add_tail(&node->link, &umem->umem_list);
-	vhost_umem_interval_tree_insert(node, &umem->umem_tree);
-	umem->numem++;
-
-	return 0;
-}
-
-static void vhost_del_umem_range(struct vhost_umem *umem,
-				 u64 start, u64 end)
-{
-	struct vhost_umem_node *node;
-
-	while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
-							   start, end)))
-		vhost_umem_free(umem, node);
-}
-
 static void vhost_iotlb_notify_vq(struct vhost_dev *d,
 				  struct vhost_iotlb_msg *msg)
 {
@@ -1120,9 +1056,9 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
 			break;
 		}
 		vhost_vq_meta_reset(dev);
-		if (vhost_new_umem_range(dev->iotlb, msg->iova, msg->size,
-					 msg->iova + msg->size - 1,
-					 msg->uaddr, msg->perm)) {
+		if (vhost_iotlb_add_range(dev->iotlb, msg->iova,
+					  msg->iova + msg->size - 1,
+					  msg->uaddr, msg->perm)) {
 			ret = -ENOMEM;
 			break;
 		}
@@ -1134,8 +1070,8 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
 			break;
 		}
 		vhost_vq_meta_reset(dev);
-		vhost_del_umem_range(dev->iotlb, msg->iova,
-				     msg->iova + msg->size - 1);
+		vhost_iotlb_del_range(dev->iotlb, msg->iova,
+				      msg->iova + msg->size - 1);
 		break;
 	default:
 		ret = -EINVAL;
@@ -1319,44 +1255,42 @@ static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
 }

 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
-				 const struct vhost_umem_node *node,
+				 const struct vhost_iotlb_map *map,
 				 int type)
 {
 	int access = (type == VHOST_ADDR_USED) ?
 		     VHOST_ACCESS_WO : VHOST_ACCESS_RO;

-	if (likely(node->perm & access))
-		vq->meta_iotlb[type] = node;
+	if (likely(map->perm & access))
+		vq->meta_iotlb[type] = map;
 }

 static bool iotlb_access_ok(struct vhost_virtqueue *vq,
 			    int access, u64 addr, u64 len, int type)
 {
-	const struct vhost_umem_node *node;
-	struct vhost_umem *umem = vq->iotlb;
+	const struct vhost_iotlb_map *map;
+	struct vhost_iotlb *umem = vq->iotlb;
 	u64 s = 0, size, orig_addr = addr, last = addr + len - 1;

 	if (vhost_vq_meta_fetch(vq, addr, len, type))
 		return true;

 	while (len > s) {
-		node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
-							   addr,
-							   last);
-		if (node == NULL || node->start > addr) {
+		map = vhost_iotlb_itree_first(umem, addr, last);
+		if (map == NULL || map->start > addr) {
 			vhost_iotlb_miss(vq, addr, access);
 			return false;
-		} else if (!(node->perm & access)) {
+		} else if (!(map->perm & access)) {
 			/* Report the possible access violation by
 			 * request another translation from userspace.
 			 */
 			return false;
 		}

-		size = node->size - addr + node->start;
+		size = map->size - addr + map->start;

 		if (orig_addr == addr && size >= len)
-			vhost_vq_meta_update(vq, node, type);
+			vhost_vq_meta_update(vq, map, type);

 		s += size;
 		addr += size;
@@ -1372,12 +1306,12 @@ int vq_meta_prefetch(struct vhost_virtqueue *vq)
 	if (!vq->iotlb)
 		return 1;

-	return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
+	return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->desc,
 			       vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
-	       iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
+	       iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->avail,
 			       vhost_get_avail_size(vq, num),
 			       VHOST_ADDR_AVAIL) &&
-	       iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
+	       iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->used,
 			       vhost_get_used_size(vq, num), VHOST_ADDR_USED);
 }
 EXPORT_SYMBOL_GPL(vq_meta_prefetch);
@@ -1416,25 +1350,11 @@ bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
 }
 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);

-static struct vhost_umem *vhost_umem_alloc(void)
-{
-	struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL);
-
-	if (!umem)
-		return NULL;
-
-	umem->umem_tree = RB_ROOT_CACHED;
-	umem->numem = 0;
-	INIT_LIST_HEAD(&umem->umem_list);
-
-	return umem;
-}
-
 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
 {
 	struct vhost_memory mem, *newmem;
 	struct vhost_memory_region *region;
-	struct vhost_umem *newumem, *oldumem;
+	struct vhost_iotlb *newumem, *oldumem;
 	unsigned long size = offsetof(struct vhost_memory, regions);
 	int i;

@@ -1456,7 +1376,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
 		return -EFAULT;
 	}

-	newumem = vhost_umem_alloc();
+	newumem = iotlb_alloc();
 	if (!newumem) {
 		kvfree(newmem);
 		return -ENOMEM;
@@ -1465,13 +1385,12 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
 	for (region = newmem->regions;
 	     region < newmem->regions + mem.nregions;
 	     region++) {
-		if (vhost_new_umem_range(newumem,
-					 region->guest_phys_addr,
-					 region->memory_size,
-					 region->guest_phys_addr +
-					 region->memory_size - 1,
-					 region->userspace_addr,
-					 VHOST_ACCESS_RW))
+		if (vhost_iotlb_add_range(newumem,
+					  region->guest_phys_addr,
+					  region->guest_phys_addr +
+					  region->memory_size - 1,
+					  region->userspace_addr,
+					  VHOST_MAP_RW))
 			goto err;
 	}

@@ -1489,11 +1408,11 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
 	}

 	kvfree(newmem);
-	vhost_umem_clean(oldumem);
+	vhost_iotlb_free(oldumem);
 	return 0;

 err:
-	vhost_umem_clean(newumem);
+	vhost_iotlb_free(newumem);
 	kvfree(newmem);
 	return -EFAULT;
 }
@@ -1734,10 +1653,10 @@ EXPORT_SYMBOL_GPL(vhost_vring_ioctl);

 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
 {
-	struct vhost_umem *niotlb, *oiotlb;
+	struct vhost_iotlb *niotlb, *oiotlb;
 	int i;

-	niotlb = vhost_umem_alloc();
+	niotlb = iotlb_alloc();
 	if (!niotlb)
 		return -ENOMEM;

@@ -1753,7 +1672,7 @@ int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
 		mutex_unlock(&vq->mutex);
 	}

-	vhost_umem_clean(oiotlb);
+	vhost_iotlb_free(oiotlb);

 	return 0;
 }
@@ -1883,8 +1802,8 @@ static int log_write(void __user *log_base,

 static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
 {
-	struct vhost_umem *umem = vq->umem;
-	struct vhost_umem_node *u;
+	struct vhost_iotlb *umem = vq->umem;
+	struct vhost_iotlb_map *u;
 	u64 start, end, l, min;
 	int r;
 	bool hit = false;
@@ -1894,16 +1813,15 @@ static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
 		/* More than one GPAs can be mapped into a single HVA. So
 		 * iterate all possible umems here to be safe.
 		 */
-		list_for_each_entry(u, &umem->umem_list, link) {
-			if (u->userspace_addr > hva - 1 + len ||
-			    u->userspace_addr - 1 + u->size < hva)
+		list_for_each_entry(u, &umem->list, link) {
+			if (u->addr > hva - 1 + len ||
+			    u->addr - 1 + u->size < hva)
 				continue;
-			start = max(u->userspace_addr, hva);
-			end = min(u->userspace_addr - 1 + u->size,
-				  hva - 1 + len);
+			start = max(u->addr, hva);
+			end = min(u->addr - 1 + u->size, hva - 1 + len);
 			l = end - start + 1;
 			r = log_write(vq->log_base,
-				      u->start + start - u->userspace_addr,
+				      u->start + start - u->addr,
 				      l);
 			if (r < 0)
 				return r;
@@ -2054,9 +1972,9 @@ EXPORT_SYMBOL_GPL(vhost_vq_init_access);
 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
 			  struct iovec iov[], int iov_size, int access)
 {
-	const struct vhost_umem_node *node;
+	const struct vhost_iotlb_map *map;
 	struct vhost_dev *dev = vq->dev;
-	struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
+	struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem;
 	struct iovec *_iov;
 	u64 s = 0;
 	int ret = 0;
@@ -2068,25 +1986,24 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
 			break;
 		}

-		node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
-							addr, addr + len - 1);
-		if (node == NULL || node->start > addr) {
+		map = vhost_iotlb_itree_first(umem, addr, addr + len - 1);
+		if (map == NULL || map->start > addr) {
 			if (umem != dev->iotlb) {
 				ret = -EFAULT;
 				break;
 			}
 			ret = -EAGAIN;
 			break;
-		} else if (!(node->perm & access)) {
+		} else if (!(map->perm & access)) {
 			ret = -EPERM;
 			break;
 		}

 		_iov = iov + ret;
-		size = node->size - addr + node->start;
+		size = map->size - addr + map->start;
 		_iov->iov_len = min((u64)len - s, size);
 		_iov->iov_base = (void __user *)(unsigned long)
-			(node->userspace_addr + addr - node->start);
+				 (map->addr + addr - map->start);
 		s += size;
 		addr += size;
 		++ret;