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* [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace
@ 2021-02-23 11:50 Xie Yongji
  2021-02-23 11:50 ` [RFC v4 01/11] eventfd: Increase the recursion depth of eventfd_signal() Xie Yongji
                   ` (10 more replies)
  0 siblings, 11 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

This series introduces a framework, which can be used to implement
vDPA Devices in a userspace program. The work consist of two parts:
control path forwarding and data path offloading.

In the control path, the VDUSE driver will make use of message
mechnism to forward the config operation from vdpa bus driver
to userspace. Userspace can use read()/write() to receive/reply
those control messages.

In the data path, the core is mapping dma buffer into VDUSE
daemon's address space, which can be implemented in different ways
depending on the vdpa bus to which the vDPA device is attached.

In virtio-vdpa case, we implements a MMU-based on-chip IOMMU driver with
bounce-buffering mechanism to achieve that. And in vhost-vdpa case, the dma
buffer is reside in a userspace memory region which can be shared to the
VDUSE userspace processs via transferring the shmfd.

The details and our user case is shown below:

------------------------    -------------------------   ----------------------------------------------
|            Container |    |              QEMU(VM) |   |                               VDUSE daemon |
|       ---------      |    |  -------------------  |   | ------------------------- ---------------- |
|       |dev/vdx|      |    |  |/dev/vhost-vdpa-x|  |   | | vDPA device emulation | | block driver | |
------------+-----------     -----------+------------   -------------+----------------------+---------
            |                           |                            |                      |
            |                           |                            |                      |
------------+---------------------------+----------------------------+----------------------+---------
|    | block device |           |  vhost device |            | vduse driver |          | TCP/IP |    |
|    -------+--------           --------+--------            -------+--------          -----+----    |
|           |                           |                           |                       |        |
| ----------+----------       ----------+-----------         -------+-------                |        |
| | virtio-blk driver |       |  vhost-vdpa driver |         | vdpa device |                |        |
| ----------+----------       ----------+-----------         -------+-------                |        |
|           |      virtio bus           |                           |                       |        |
|   --------+----+-----------           |                           |                       |        |
|                |                      |                           |                       |        |
|      ----------+----------            |                           |                       |        |
|      | virtio-blk device |            |                           |                       |        |
|      ----------+----------            |                           |                       |        |
|                |                      |                           |                       |        |
|     -----------+-----------           |                           |                       |        |
|     |  virtio-vdpa driver |           |                           |                       |        |
|     -----------+-----------           |                           |                       |        |
|                |                      |                           |    vdpa bus           |        |
|     -----------+----------------------+---------------------------+------------           |        |
|                                                                                        ---+---     |
-----------------------------------------------------------------------------------------| NIC |------
                                                                                         ---+---
                                                                                            |
                                                                                   ---------+---------
                                                                                   | Remote Storages |
                                                                                   -------------------

We make use of it to implement a block device connecting to
our distributed storage, which can be used both in containers and
VMs. Thus, we can have an unified technology stack in this two cases.

To test it with null-blk:

  $ qemu-storage-daemon \
      --chardev socket,id=charmonitor,path=/tmp/qmp.sock,server,nowait \
      --monitor chardev=charmonitor \
      --blockdev driver=host_device,cache.direct=on,aio=native,filename=/dev/nullb0,node-name=disk0 \
      --export type=vduse-blk,id=test,node-name=disk0,writable=on,name=vduse-null,num-queues=16,queue-size=128

The qemu-storage-daemon can be found at https://github.com/bytedance/qemu/tree/vduse

Future work:
  - Improve performance
  - Userspace library (find a way to reuse device emulation code in qemu/rust-vmm)

V3 to V4:
- Rebase to vhost.git
- Split some patches
- Add some documents
- Use ioctl to inject interrupt rather than eventfd
- Enable config interrupt support
- Support binding irq to the specified cpu
- Add two module parameter to limit bounce/iova size
- Create char device rather than anon inode per vduse
- Reuse vhost IOTLB for iova domain
- Rework the message mechnism in control path

V2 to V3:
- Rework the MMU-based IOMMU driver
- Use the iova domain as iova allocator instead of genpool
- Support transferring vma->vm_file in vhost-vdpa
- Add SVA support in vhost-vdpa
- Remove the patches on bounce pages reclaim

V1 to V2:
- Add vhost-vdpa support
- Add some documents
- Based on the vdpa management tool
- Introduce a workqueue for irq injection
- Replace interval tree with array map to store the iova_map

Xie Yongji (11):
  eventfd: Increase the recursion depth of eventfd_signal()
  vhost-vdpa: protect concurrent access to vhost device iotlb
  vhost-iotlb: Add an opaque pointer for vhost IOTLB
  vdpa: Add an opaque pointer for vdpa_config_ops.dma_map()
  vdpa: Support transferring virtual addressing during DMA mapping
  vduse: Implement an MMU-based IOMMU driver
  vduse: Introduce VDUSE - vDPA Device in Userspace
  vduse: Add config interrupt support
  Documentation: Add documentation for VDUSE
  vduse: Introduce a workqueue for irq injection
  vduse: Support binding irq to the specified cpu

 Documentation/userspace-api/index.rst              |    1 +
 Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +
 Documentation/userspace-api/vduse.rst              |  112 ++
 drivers/vdpa/Kconfig                               |   10 +
 drivers/vdpa/Makefile                              |    1 +
 drivers/vdpa/ifcvf/ifcvf_main.c                    |    2 +-
 drivers/vdpa/mlx5/net/mlx5_vnet.c                  |    2 +-
 drivers/vdpa/vdpa.c                                |    9 +-
 drivers/vdpa/vdpa_sim/vdpa_sim.c                   |    8 +-
 drivers/vdpa/vdpa_user/Makefile                    |    5 +
 drivers/vdpa/vdpa_user/iova_domain.c               |  486 +++++++
 drivers/vdpa/vdpa_user/iova_domain.h               |   61 +
 drivers/vdpa/vdpa_user/vduse_dev.c                 | 1399 ++++++++++++++++++++
 drivers/vhost/iotlb.c                              |   20 +-
 drivers/vhost/vdpa.c                               |  106 +-
 fs/eventfd.c                                       |    2 +-
 include/linux/eventfd.h                            |    5 +-
 include/linux/vdpa.h                               |   22 +-
 include/linux/vhost_iotlb.h                        |    3 +
 include/uapi/linux/vduse.h                         |  144 ++
 20 files changed, 2363 insertions(+), 36 deletions(-)
 create mode 100644 Documentation/userspace-api/vduse.rst
 create mode 100644 drivers/vdpa/vdpa_user/Makefile
 create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c
 create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h
 create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
 create mode 100644 include/uapi/linux/vduse.h

-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 01/11] eventfd: Increase the recursion depth of eventfd_signal()
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 02/11] vhost-vdpa: protect concurrent access to vhost device iotlb Xie Yongji
                   ` (9 subsequent siblings)
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

Increase the recursion depth of eventfd_signal() to 1. This
is the maximum recursion depth we have found so far.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 fs/eventfd.c            | 2 +-
 include/linux/eventfd.h | 5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/eventfd.c b/fs/eventfd.c
index e265b6dd4f34..cc7cd1dbedd3 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -71,7 +71,7 @@ __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
 	 * it returns true, the eventfd_signal() call should be deferred to a
 	 * safe context.
 	 */
-	if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count)))
+	if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count) > EFD_WAKE_DEPTH))
 		return 0;
 
 	spin_lock_irqsave(&ctx->wqh.lock, flags);
diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
index fa0a524baed0..886d99cd38ef 100644
--- a/include/linux/eventfd.h
+++ b/include/linux/eventfd.h
@@ -29,6 +29,9 @@
 #define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
 #define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
 
+/* Maximum recursion depth */
+#define EFD_WAKE_DEPTH 1
+
 struct eventfd_ctx;
 struct file;
 
@@ -47,7 +50,7 @@ DECLARE_PER_CPU(int, eventfd_wake_count);
 
 static inline bool eventfd_signal_count(void)
 {
-	return this_cpu_read(eventfd_wake_count);
+	return this_cpu_read(eventfd_wake_count) > EFD_WAKE_DEPTH;
 }
 
 #else /* CONFIG_EVENTFD */
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 02/11] vhost-vdpa: protect concurrent access to vhost device iotlb
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
  2021-02-23 11:50 ` [RFC v4 01/11] eventfd: Increase the recursion depth of eventfd_signal() Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 03/11] vhost-iotlb: Add an opaque pointer for vhost IOTLB Xie Yongji
                   ` (8 subsequent siblings)
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

Use vhost_dev->mutex to protect vhost device iotlb from
concurrent access.

Fixes: 4c8cf318("vhost: introduce vDPA-based backend")
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vhost/vdpa.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index c50079dfb281..5500e3bf05c1 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -723,6 +723,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
 	if (r)
 		return r;
 
+	mutex_lock(&dev->mutex);
 	switch (msg->type) {
 	case VHOST_IOTLB_UPDATE:
 		r = vhost_vdpa_process_iotlb_update(v, msg);
@@ -742,6 +743,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
 		r = -EINVAL;
 		break;
 	}
+	mutex_unlock(&dev->mutex);
 
 	return r;
 }
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 03/11] vhost-iotlb: Add an opaque pointer for vhost IOTLB
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
  2021-02-23 11:50 ` [RFC v4 01/11] eventfd: Increase the recursion depth of eventfd_signal() Xie Yongji
  2021-02-23 11:50 ` [RFC v4 02/11] vhost-vdpa: protect concurrent access to vhost device iotlb Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 04/11] vdpa: Add an opaque pointer for vdpa_config_ops.dma_map() Xie Yongji
                   ` (7 subsequent siblings)
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

Add an opaque pointer for vhost IOTLB. And introduce
vhost_iotlb_add_range_ctx() to accept it.

Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vhost/iotlb.c       | 20 ++++++++++++++++----
 include/linux/vhost_iotlb.h |  3 +++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/vhost/iotlb.c b/drivers/vhost/iotlb.c
index 0fd3f87e913c..5c99e1112cbb 100644
--- a/drivers/vhost/iotlb.c
+++ b/drivers/vhost/iotlb.c
@@ -36,19 +36,21 @@ void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
 EXPORT_SYMBOL_GPL(vhost_iotlb_map_free);
 
 /**
- * vhost_iotlb_add_range - add a new range to vhost IOTLB
+ * vhost_iotlb_add_range_ctx - add a new range to vhost IOTLB
  * @iotlb: the IOTLB
  * @start: start of the IOVA range
  * @last: last of IOVA range
  * @addr: the address that is mapped to @start
  * @perm: access permission of this range
+ * @opaque: the opaque pointer for the new mapping
  *
  * Returns an error last is smaller than start or memory allocation
  * fails
  */
-int vhost_iotlb_add_range(struct vhost_iotlb *iotlb,
-			  u64 start, u64 last,
-			  u64 addr, unsigned int perm)
+int vhost_iotlb_add_range_ctx(struct vhost_iotlb *iotlb,
+			      u64 start, u64 last,
+			      u64 addr, unsigned int perm,
+			      void *opaque)
 {
 	struct vhost_iotlb_map *map;
 
@@ -71,6 +73,7 @@ int vhost_iotlb_add_range(struct vhost_iotlb *iotlb,
 	map->last = last;
 	map->addr = addr;
 	map->perm = perm;
+	map->opaque = opaque;
 
 	iotlb->nmaps++;
 	vhost_iotlb_itree_insert(map, &iotlb->root);
@@ -80,6 +83,15 @@ int vhost_iotlb_add_range(struct vhost_iotlb *iotlb,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(vhost_iotlb_add_range_ctx);
+
+int vhost_iotlb_add_range(struct vhost_iotlb *iotlb,
+			  u64 start, u64 last,
+			  u64 addr, unsigned int perm)
+{
+	return vhost_iotlb_add_range_ctx(iotlb, start, last,
+					 addr, perm, NULL);
+}
 EXPORT_SYMBOL_GPL(vhost_iotlb_add_range);
 
 /**
diff --git a/include/linux/vhost_iotlb.h b/include/linux/vhost_iotlb.h
index 6b09b786a762..2d0e2f52f938 100644
--- a/include/linux/vhost_iotlb.h
+++ b/include/linux/vhost_iotlb.h
@@ -17,6 +17,7 @@ struct vhost_iotlb_map {
 	u32 perm;
 	u32 flags_padding;
 	u64 __subtree_last;
+	void *opaque;
 };
 
 #define VHOST_IOTLB_FLAG_RETIRE 0x1
@@ -29,6 +30,8 @@ struct vhost_iotlb {
 	unsigned int flags;
 };
 
+int vhost_iotlb_add_range_ctx(struct vhost_iotlb *iotlb, u64 start, u64 last,
+			      u64 addr, unsigned int perm, void *opaque);
 int vhost_iotlb_add_range(struct vhost_iotlb *iotlb, u64 start, u64 last,
 			  u64 addr, unsigned int perm);
 void vhost_iotlb_del_range(struct vhost_iotlb *iotlb, u64 start, u64 last);
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 04/11] vdpa: Add an opaque pointer for vdpa_config_ops.dma_map()
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
                   ` (2 preceding siblings ...)
  2021-02-23 11:50 ` [RFC v4 03/11] vhost-iotlb: Add an opaque pointer for vhost IOTLB Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 05/11] vdpa: Support transferring virtual addressing during DMA mapping Xie Yongji
                   ` (6 subsequent siblings)
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

Add an opaque pointer for DMA mapping.

Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim.c | 6 +++---
 drivers/vhost/vdpa.c             | 2 +-
 include/linux/vdpa.h             | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index d5942842432d..5cfc262ce055 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -512,14 +512,14 @@ static int vdpasim_set_map(struct vdpa_device *vdpa,
 }
 
 static int vdpasim_dma_map(struct vdpa_device *vdpa, u64 iova, u64 size,
-			   u64 pa, u32 perm)
+			   u64 pa, u32 perm, void *opaque)
 {
 	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 	int ret;
 
 	spin_lock(&vdpasim->iommu_lock);
-	ret = vhost_iotlb_add_range(vdpasim->iommu, iova, iova + size - 1, pa,
-				    perm);
+	ret = vhost_iotlb_add_range_ctx(vdpasim->iommu, iova, iova + size - 1,
+					pa, perm, opaque);
 	spin_unlock(&vdpasim->iommu_lock);
 
 	return ret;
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 5500e3bf05c1..70857fe3263c 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -544,7 +544,7 @@ static int vhost_vdpa_map(struct vhost_vdpa *v,
 		return r;
 
 	if (ops->dma_map) {
-		r = ops->dma_map(vdpa, iova, size, pa, perm);
+		r = ops->dma_map(vdpa, iova, size, pa, perm, NULL);
 	} else if (ops->set_map) {
 		if (!v->in_batch)
 			r = ops->set_map(vdpa, dev->iotlb);
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 4ab5494503a8..93dca2c328ae 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -241,7 +241,7 @@ struct vdpa_config_ops {
 	/* DMA ops */
 	int (*set_map)(struct vdpa_device *vdev, struct vhost_iotlb *iotlb);
 	int (*dma_map)(struct vdpa_device *vdev, u64 iova, u64 size,
-		       u64 pa, u32 perm);
+		       u64 pa, u32 perm, void *opaque);
 	int (*dma_unmap)(struct vdpa_device *vdev, u64 iova, u64 size);
 
 	/* Free device resources */
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 05/11] vdpa: Support transferring virtual addressing during DMA mapping
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
                   ` (3 preceding siblings ...)
  2021-02-23 11:50 ` [RFC v4 04/11] vdpa: Add an opaque pointer for vdpa_config_ops.dma_map() Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 06/11] vduse: Implement an MMU-based IOMMU driver Xie Yongji
                   ` (5 subsequent siblings)
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

This patch introduces an attribute for vDPA device to indicate
whether virtual address can be used. If vDPA device driver set
it, vhost-vdpa bus driver will not pin user page and transfer
userspace virtual address instead of physical address during
DMA mapping. And corresponding vma->vm_file and offset will be
also passed as an opaque pointer.

Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vdpa/ifcvf/ifcvf_main.c   |   2 +-
 drivers/vdpa/mlx5/net/mlx5_vnet.c |   2 +-
 drivers/vdpa/vdpa.c               |   9 +++-
 drivers/vdpa/vdpa_sim/vdpa_sim.c  |   2 +-
 drivers/vhost/vdpa.c              | 104 +++++++++++++++++++++++++++++++-------
 include/linux/vdpa.h              |  20 ++++++--
 6 files changed, 113 insertions(+), 26 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index 7c8bbfcf6c3e..228b9f920fea 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -432,7 +432,7 @@ static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	adapter = vdpa_alloc_device(struct ifcvf_adapter, vdpa,
 				    dev, &ifc_vdpa_ops,
-				    IFCVF_MAX_QUEUE_PAIRS * 2, NULL);
+				    IFCVF_MAX_QUEUE_PAIRS * 2, NULL, false);
 	if (adapter == NULL) {
 		IFCVF_ERR(pdev, "Failed to allocate vDPA structure");
 		return -ENOMEM;
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 029822060017..54290438da28 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1964,7 +1964,7 @@ static int mlx5v_probe(struct auxiliary_device *adev,
 	max_vqs = min_t(u32, max_vqs, MLX5_MAX_SUPPORTED_VQS);
 
 	ndev = vdpa_alloc_device(struct mlx5_vdpa_net, mvdev.vdev, mdev->device, &mlx5_vdpa_ops,
-				 2 * mlx5_vdpa_max_qps(max_vqs), NULL);
+				 2 * mlx5_vdpa_max_qps(max_vqs), NULL, false);
 	if (IS_ERR(ndev))
 		return PTR_ERR(ndev);
 
diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 9700a0adcca0..fafc0ee5eb05 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -72,6 +72,7 @@ static void vdpa_release_dev(struct device *d)
  * @nvqs: number of virtqueues supported by this device
  * @size: size of the parent structure that contains private data
  * @name: name of the vdpa device; optional.
+ * @use_va: indicate whether virtual address can be used by this device
  *
  * Driver should use vdpa_alloc_device() wrapper macro instead of
  * using this directly.
@@ -81,7 +82,8 @@ static void vdpa_release_dev(struct device *d)
  */
 struct vdpa_device *__vdpa_alloc_device(struct device *parent,
 					const struct vdpa_config_ops *config,
-					int nvqs, size_t size, const char *name)
+					int nvqs, size_t size, const char *name,
+					bool use_va)
 {
 	struct vdpa_device *vdev;
 	int err = -EINVAL;
@@ -92,6 +94,10 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
 	if (!!config->dma_map != !!config->dma_unmap)
 		goto err;
 
+	/* It should only work for the device that use on-chip IOMMU */
+	if (use_va && !(config->dma_map || config->set_map))
+		goto err;
+
 	err = -ENOMEM;
 	vdev = kzalloc(size, GFP_KERNEL);
 	if (!vdev)
@@ -108,6 +114,7 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
 	vdev->config = config;
 	vdev->features_valid = false;
 	vdev->nvqs = nvqs;
+	vdev->use_va = use_va;
 
 	if (name)
 		err = dev_set_name(&vdev->dev, "%s", name);
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 5cfc262ce055..3a9a2dd4e987 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -235,7 +235,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr)
 		ops = &vdpasim_config_ops;
 
 	vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
-				    dev_attr->nvqs, dev_attr->name);
+				    dev_attr->nvqs, dev_attr->name, false);
 	if (!vdpasim)
 		goto err_alloc;
 
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 70857fe3263c..93769ace34df 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -480,21 +480,31 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
 static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v, u64 start, u64 last)
 {
 	struct vhost_dev *dev = &v->vdev;
+	struct vdpa_device *vdpa = v->vdpa;
 	struct vhost_iotlb *iotlb = dev->iotlb;
 	struct vhost_iotlb_map *map;
+	struct vdpa_map_file *map_file;
 	struct page *page;
 	unsigned long pfn, pinned;
 
 	while ((map = vhost_iotlb_itree_first(iotlb, start, last)) != NULL) {
-		pinned = map->size >> PAGE_SHIFT;
-		for (pfn = map->addr >> PAGE_SHIFT;
-		     pinned > 0; pfn++, pinned--) {
-			page = pfn_to_page(pfn);
-			if (map->perm & VHOST_ACCESS_WO)
-				set_page_dirty_lock(page);
-			unpin_user_page(page);
+		if (!vdpa->use_va) {
+			pinned = map->size >> PAGE_SHIFT;
+			for (pfn = map->addr >> PAGE_SHIFT;
+			     pinned > 0; pfn++, pinned--) {
+				page = pfn_to_page(pfn);
+				if (map->perm & VHOST_ACCESS_WO)
+					set_page_dirty_lock(page);
+				unpin_user_page(page);
+			}
+			atomic64_sub(map->size >> PAGE_SHIFT,
+					&dev->mm->pinned_vm);
+		} else {
+			map_file = (struct vdpa_map_file *)map->opaque;
+			if (map_file->file)
+				fput(map_file->file);
+			kfree(map_file);
 		}
-		atomic64_sub(map->size >> PAGE_SHIFT, &dev->mm->pinned_vm);
 		vhost_iotlb_map_free(iotlb, map);
 	}
 }
@@ -530,21 +540,21 @@ static int perm_to_iommu_flags(u32 perm)
 	return flags | IOMMU_CACHE;
 }
 
-static int vhost_vdpa_map(struct vhost_vdpa *v,
-			  u64 iova, u64 size, u64 pa, u32 perm)
+static int vhost_vdpa_map(struct vhost_vdpa *v, u64 iova,
+			  u64 size, u64 pa, u32 perm, void *opaque)
 {
 	struct vhost_dev *dev = &v->vdev;
 	struct vdpa_device *vdpa = v->vdpa;
 	const struct vdpa_config_ops *ops = vdpa->config;
 	int r = 0;
 
-	r = vhost_iotlb_add_range(dev->iotlb, iova, iova + size - 1,
-				  pa, perm);
+	r = vhost_iotlb_add_range_ctx(dev->iotlb, iova, iova + size - 1,
+				      pa, perm, opaque);
 	if (r)
 		return r;
 
 	if (ops->dma_map) {
-		r = ops->dma_map(vdpa, iova, size, pa, perm, NULL);
+		r = ops->dma_map(vdpa, iova, size, pa, perm, opaque);
 	} else if (ops->set_map) {
 		if (!v->in_batch)
 			r = ops->set_map(vdpa, dev->iotlb);
@@ -552,13 +562,15 @@ static int vhost_vdpa_map(struct vhost_vdpa *v,
 		r = iommu_map(v->domain, iova, pa, size,
 			      perm_to_iommu_flags(perm));
 	}
-
-	if (r)
+	if (r) {
 		vhost_iotlb_del_range(dev->iotlb, iova, iova + size - 1);
-	else
+		return r;
+	}
+
+	if (!vdpa->use_va)
 		atomic64_add(size >> PAGE_SHIFT, &dev->mm->pinned_vm);
 
-	return r;
+	return 0;
 }
 
 static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size)
@@ -579,10 +591,60 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size)
 	}
 }
 
+static int vhost_vdpa_va_map(struct vhost_vdpa *v,
+			     u64 iova, u64 size, u64 uaddr, u32 perm)
+{
+	struct vhost_dev *dev = &v->vdev;
+	u64 offset, map_size, map_iova = iova;
+	struct vdpa_map_file *map_file;
+	struct vm_area_struct *vma;
+	int ret;
+
+	mmap_read_lock(dev->mm);
+
+	while (size) {
+		vma = find_vma(dev->mm, uaddr);
+		if (!vma) {
+			ret = -EINVAL;
+			goto err;
+		}
+		map_size = min(size, vma->vm_end - uaddr);
+		offset = (vma->vm_pgoff << PAGE_SHIFT) + uaddr - vma->vm_start;
+		map_file = kzalloc(sizeof(*map_file), GFP_KERNEL);
+		if (!map_file) {
+			ret = -ENOMEM;
+			goto err;
+		}
+		if (vma->vm_file && (vma->vm_flags & VM_SHARED) &&
+			!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
+			map_file->file = get_file(vma->vm_file);
+			map_file->offset = offset;
+		}
+		ret = vhost_vdpa_map(v, map_iova, map_size, uaddr,
+				     perm, map_file);
+		if (ret) {
+			if (map_file->file)
+				fput(map_file->file);
+			kfree(map_file);
+			goto err;
+		}
+		size -= map_size;
+		uaddr += map_size;
+		map_iova += map_size;
+	}
+	mmap_read_unlock(dev->mm);
+
+	return 0;
+err:
+	vhost_vdpa_unmap(v, iova, map_iova - iova);
+	return ret;
+}
+
 static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 					   struct vhost_iotlb_msg *msg)
 {
 	struct vhost_dev *dev = &v->vdev;
+	struct vdpa_device *vdpa = v->vdpa;
 	struct vhost_iotlb *iotlb = dev->iotlb;
 	struct page **page_list;
 	unsigned long list_size = PAGE_SIZE / sizeof(struct page *);
@@ -601,6 +663,10 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 				    msg->iova + msg->size - 1))
 		return -EEXIST;
 
+	if (vdpa->use_va)
+		return vhost_vdpa_va_map(v, msg->iova, msg->size,
+					 msg->uaddr, msg->perm);
+
 	/* Limit the use of memory for bookkeeping */
 	page_list = (struct page **) __get_free_page(GFP_KERNEL);
 	if (!page_list)
@@ -654,7 +720,7 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 				csize = (last_pfn - map_pfn + 1) << PAGE_SHIFT;
 				ret = vhost_vdpa_map(v, iova, csize,
 						     map_pfn << PAGE_SHIFT,
-						     msg->perm);
+						     msg->perm, NULL);
 				if (ret) {
 					/*
 					 * Unpin the pages that are left unmapped
@@ -683,7 +749,7 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 
 	/* Pin the rest chunk */
 	ret = vhost_vdpa_map(v, iova, (last_pfn - map_pfn + 1) << PAGE_SHIFT,
-			     map_pfn << PAGE_SHIFT, msg->perm);
+			     map_pfn << PAGE_SHIFT, msg->perm, NULL);
 out:
 	if (ret) {
 		if (nchunks) {
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 93dca2c328ae..bfae6d780c38 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -44,6 +44,7 @@ struct vdpa_mgmt_dev;
  * @config: the configuration ops for this device.
  * @index: device index
  * @features_valid: were features initialized? for legacy guests
+ * @use_va: indicate whether virtual address can be used by this device
  * @nvqs: maximum number of supported virtqueues
  * @mdev: management device pointer; caller must setup when registering device as part
  *	  of dev_add() mgmtdev ops callback before invoking _vdpa_register_device().
@@ -54,6 +55,7 @@ struct vdpa_device {
 	const struct vdpa_config_ops *config;
 	unsigned int index;
 	bool features_valid;
+	bool use_va;
 	int nvqs;
 	struct vdpa_mgmt_dev *mdev;
 };
@@ -69,6 +71,16 @@ struct vdpa_iova_range {
 };
 
 /**
+ * Corresponding file area for device memory mapping
+ * @file: vma->vm_file for the mapping
+ * @offset: mapping offset in the vm_file
+ */
+struct vdpa_map_file {
+	struct file *file;
+	u64 offset;
+};
+
+/**
  * vDPA_config_ops - operations for configuring a vDPA device.
  * Note: vDPA device drivers are required to implement all of the
  * operations unless it is mentioned to be optional in the following
@@ -250,14 +262,16 @@ struct vdpa_config_ops {
 
 struct vdpa_device *__vdpa_alloc_device(struct device *parent,
 					const struct vdpa_config_ops *config,
-					int nvqs, size_t size, const char *name);
+					int nvqs, size_t size,
+					const char *name, bool use_va);
 
-#define vdpa_alloc_device(dev_struct, member, parent, config, nvqs, name)   \
+#define vdpa_alloc_device(dev_struct, member, parent, config, \
+			  nvqs, name, use_va) \
 			  container_of(__vdpa_alloc_device( \
 				       parent, config, nvqs, \
 				       sizeof(dev_struct) + \
 				       BUILD_BUG_ON_ZERO(offsetof( \
-				       dev_struct, member)), name), \
+				       dev_struct, member)), name, use_va), \
 				       dev_struct, member)
 
 int vdpa_register_device(struct vdpa_device *vdev);
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 06/11] vduse: Implement an MMU-based IOMMU driver
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
                   ` (4 preceding siblings ...)
  2021-02-23 11:50 ` [RFC v4 05/11] vdpa: Support transferring virtual addressing during DMA mapping Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 07/11] vduse: Introduce VDUSE - vDPA Device in Userspace Xie Yongji
                   ` (4 subsequent siblings)
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

This implements a MMU-based IOMMU driver to support mapping
kernel dma buffer into userspace. The basic idea behind it is
treating MMU (VA->PA) as IOMMU (IOVA->PA). The driver will set
up MMU mapping instead of IOMMU mapping for the DMA transfer so
that the userspace process is able to use its virtual address to
access the dma buffer in kernel.

And to avoid security issue, a bounce-buffering mechanism is
introduced to prevent userspace accessing the original buffer
directly.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vdpa/vdpa_user/iova_domain.c | 486 +++++++++++++++++++++++++++++++++++
 drivers/vdpa/vdpa_user/iova_domain.h |  61 +++++
 2 files changed, 547 insertions(+)
 create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c
 create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h

diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
new file mode 100644
index 000000000000..9285d430d486
--- /dev/null
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -0,0 +1,486 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MMU-based IOMMU implementation
+ *
+ * Copyright (C) 2020 Bytedance Inc. and/or its affiliates. All rights reserved.
+ *
+ * Author: Xie Yongji <xieyongji@bytedance.com>
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/anon_inodes.h>
+#include <linux/highmem.h>
+
+#include "iova_domain.h"
+
+#define IOVA_START_PFN 1
+#define IOVA_ALLOC_ORDER 12
+#define IOVA_ALLOC_SIZE (1 << IOVA_ALLOC_ORDER)
+
+static inline struct page *
+vduse_domain_get_bounce_page(struct vduse_iova_domain *domain, u64 iova)
+{
+	u64 index = iova >> PAGE_SHIFT;
+
+	return domain->bounce_pages[index];
+}
+
+static inline void
+vduse_domain_set_bounce_page(struct vduse_iova_domain *domain,
+				u64 iova, struct page *page)
+{
+	u64 index = iova >> PAGE_SHIFT;
+
+	domain->bounce_pages[index] = page;
+}
+
+static enum dma_data_direction perm_to_dir(int perm)
+{
+	enum dma_data_direction dir;
+
+	switch (perm) {
+	case VHOST_MAP_WO:
+		dir = DMA_FROM_DEVICE;
+		break;
+	case VHOST_MAP_RO:
+		dir = DMA_TO_DEVICE;
+		break;
+	case VHOST_MAP_RW:
+		dir = DMA_BIDIRECTIONAL;
+		break;
+	default:
+		break;
+	}
+
+	return dir;
+}
+
+static int dir_to_perm(enum dma_data_direction dir)
+{
+	int perm = -EFAULT;
+
+	switch (dir) {
+	case DMA_FROM_DEVICE:
+		perm = VHOST_MAP_WO;
+		break;
+	case DMA_TO_DEVICE:
+		perm = VHOST_MAP_RO;
+		break;
+	case DMA_BIDIRECTIONAL:
+		perm = VHOST_MAP_RW;
+		break;
+	default:
+		break;
+	}
+
+	return perm;
+}
+
+static void do_bounce(phys_addr_t orig, void *addr, size_t size,
+			enum dma_data_direction dir)
+{
+	unsigned long pfn = PFN_DOWN(orig);
+
+	if (PageHighMem(pfn_to_page(pfn))) {
+		unsigned int offset = offset_in_page(orig);
+		char *buffer;
+		unsigned int sz = 0;
+		unsigned long flags;
+
+		while (size) {
+			sz = min_t(size_t, PAGE_SIZE - offset, size);
+
+			local_irq_save(flags);
+			buffer = kmap_atomic(pfn_to_page(pfn));
+			if (dir == DMA_TO_DEVICE)
+				memcpy(addr, buffer + offset, sz);
+			else
+				memcpy(buffer + offset, addr, sz);
+			kunmap_atomic(buffer);
+			local_irq_restore(flags);
+
+			size -= sz;
+			pfn++;
+			addr += sz;
+			offset = 0;
+		}
+	} else if (dir == DMA_TO_DEVICE) {
+		memcpy(addr, phys_to_virt(orig), size);
+	} else {
+		memcpy(phys_to_virt(orig), addr, size);
+	}
+}
+
+static struct page *
+vduse_domain_get_mapping_page(struct vduse_iova_domain *domain, u64 iova)
+{
+	u64 start = iova & PAGE_MASK;
+	u64 last = start + PAGE_SIZE - 1;
+	struct vhost_iotlb_map *map;
+	struct page *page = NULL;
+
+	spin_lock(&domain->iotlb_lock);
+	map = vhost_iotlb_itree_first(domain->iotlb, start, last);
+	if (!map)
+		goto out;
+
+	page = pfn_to_page((map->addr + iova - map->start) >> PAGE_SHIFT);
+	get_page(page);
+out:
+	spin_unlock(&domain->iotlb_lock);
+
+	return page;
+}
+
+static struct page *
+vduse_domain_alloc_bounce_page(struct vduse_iova_domain *domain, u64 iova)
+{
+	u64 start = iova & PAGE_MASK;
+	u64 last = start + PAGE_SIZE - 1;
+	struct vhost_iotlb_map *map;
+	struct page *page = NULL, *new_page = alloc_page(GFP_KERNEL);
+
+	if (!new_page)
+		return NULL;
+
+	spin_lock(&domain->iotlb_lock);
+	if (!vhost_iotlb_itree_first(domain->iotlb, start, last)) {
+		__free_page(new_page);
+		goto out;
+	}
+	page = vduse_domain_get_bounce_page(domain, iova);
+	if (page) {
+		get_page(page);
+		__free_page(new_page);
+		goto out;
+	}
+	vduse_domain_set_bounce_page(domain, iova, new_page);
+	get_page(new_page);
+	page = new_page;
+
+	for (map = vhost_iotlb_itree_first(domain->iotlb, start, last); map;
+	     map = vhost_iotlb_itree_next(map, start, last)) {
+		unsigned int src_offset = 0, dst_offset = 0;
+		phys_addr_t src;
+		void *dst;
+		size_t sz;
+
+		if (perm_to_dir(map->perm) == DMA_FROM_DEVICE)
+			continue;
+
+		if (start > map->start)
+			src_offset = start - map->start;
+		else
+			dst_offset = map->start - start;
+
+		src = map->addr + src_offset;
+		dst = page_address(page) + dst_offset;
+		sz = min_t(size_t, map->size - src_offset,
+				PAGE_SIZE - dst_offset);
+		do_bounce(src, dst, sz, DMA_TO_DEVICE);
+	}
+out:
+	spin_unlock(&domain->iotlb_lock);
+
+	return page;
+}
+
+static void
+vduse_domain_free_bounce_pages(struct vduse_iova_domain *domain,
+				u64 iova, size_t size)
+{
+	struct page *page;
+
+	spin_lock(&domain->iotlb_lock);
+	if (WARN_ON(vhost_iotlb_itree_first(domain->iotlb, iova,
+						iova + size - 1)))
+		goto out;
+
+	while (size > 0) {
+		page = vduse_domain_get_bounce_page(domain, iova);
+		if (page) {
+			vduse_domain_set_bounce_page(domain, iova, NULL);
+			__free_page(page);
+		}
+		size -= PAGE_SIZE;
+		iova += PAGE_SIZE;
+	}
+out:
+	spin_unlock(&domain->iotlb_lock);
+}
+
+static void vduse_domain_bounce(struct vduse_iova_domain *domain,
+				dma_addr_t iova, phys_addr_t orig,
+				size_t size, enum dma_data_direction dir)
+{
+	unsigned int offset = offset_in_page(iova);
+
+	while (size) {
+		struct page *p = vduse_domain_get_bounce_page(domain, iova);
+		size_t sz = min_t(size_t, PAGE_SIZE - offset, size);
+
+		WARN_ON(!p && dir == DMA_FROM_DEVICE);
+
+		if (p)
+			do_bounce(orig, page_address(p) + offset, sz, dir);
+
+		size -= sz;
+		orig += sz;
+		iova += sz;
+		offset = 0;
+	}
+}
+
+static dma_addr_t vduse_domain_alloc_iova(struct iova_domain *iovad,
+				unsigned long size, unsigned long limit)
+{
+	unsigned long shift = iova_shift(iovad);
+	unsigned long iova_len = iova_align(iovad, size) >> shift;
+	unsigned long iova_pfn;
+
+	if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
+		iova_len = roundup_pow_of_two(iova_len);
+	iova_pfn = alloc_iova_fast(iovad, iova_len, limit >> shift, true);
+
+	return iova_pfn << shift;
+}
+
+static void vduse_domain_free_iova(struct iova_domain *iovad,
+				dma_addr_t iova, size_t size)
+{
+	unsigned long shift = iova_shift(iovad);
+	unsigned long iova_len = iova_align(iovad, size) >> shift;
+
+	free_iova_fast(iovad, iova >> shift, iova_len);
+}
+
+dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain,
+				struct page *page, unsigned long offset,
+				size_t size, enum dma_data_direction dir,
+				unsigned long attrs)
+{
+	struct iova_domain *iovad = &domain->stream_iovad;
+	unsigned long limit = domain->bounce_size - 1;
+	phys_addr_t pa = page_to_phys(page) + offset;
+	dma_addr_t iova = vduse_domain_alloc_iova(iovad, size, limit);
+	int ret;
+
+	if (!iova)
+		return DMA_MAPPING_ERROR;
+
+	spin_lock(&domain->iotlb_lock);
+	ret = vhost_iotlb_add_range(domain->iotlb, (u64)iova,
+				    (u64)iova + size - 1,
+				    pa, dir_to_perm(dir));
+	spin_unlock(&domain->iotlb_lock);
+	if (ret) {
+		vduse_domain_free_iova(iovad, iova, size);
+		return DMA_MAPPING_ERROR;
+	}
+	if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
+		vduse_domain_bounce(domain, iova, pa, size, DMA_TO_DEVICE);
+
+	return iova;
+}
+
+void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
+			dma_addr_t dma_addr, size_t size,
+			enum dma_data_direction dir, unsigned long attrs)
+{
+	struct iova_domain *iovad = &domain->stream_iovad;
+	struct vhost_iotlb_map *map;
+	phys_addr_t pa;
+
+	spin_lock(&domain->iotlb_lock);
+	map = vhost_iotlb_itree_first(domain->iotlb, (u64)dma_addr,
+				      (u64)dma_addr + size - 1);
+	if (WARN_ON(!map)) {
+		spin_unlock(&domain->iotlb_lock);
+		return;
+	}
+	pa = map->addr;
+	vhost_iotlb_map_free(domain->iotlb, map);
+	spin_unlock(&domain->iotlb_lock);
+
+	if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
+		vduse_domain_bounce(domain, dma_addr, pa,
+					size, DMA_FROM_DEVICE);
+
+	vduse_domain_free_iova(iovad, dma_addr, size);
+}
+
+void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
+				size_t size, dma_addr_t *dma_addr,
+				gfp_t flag, unsigned long attrs)
+{
+	struct iova_domain *iovad = &domain->consistent_iovad;
+	unsigned long limit = domain->iova_limit;
+	dma_addr_t iova = vduse_domain_alloc_iova(iovad, size, limit);
+	void *orig = alloc_pages_exact(size, flag);
+	int ret;
+
+	if (!iova || !orig)
+		goto err;
+
+	spin_lock(&domain->iotlb_lock);
+	ret = vhost_iotlb_add_range(domain->iotlb, (u64)iova,
+				    (u64)iova + size - 1,
+				    virt_to_phys(orig), VHOST_MAP_RW);
+	spin_unlock(&domain->iotlb_lock);
+	if (ret)
+		goto err;
+
+	*dma_addr = iova;
+
+	return orig;
+err:
+	*dma_addr = DMA_MAPPING_ERROR;
+	if (orig)
+		free_pages_exact(orig, size);
+	if (iova)
+		vduse_domain_free_iova(iovad, iova, size);
+
+	return NULL;
+}
+
+void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
+				void *vaddr, dma_addr_t dma_addr,
+				unsigned long attrs)
+{
+	struct iova_domain *iovad = &domain->consistent_iovad;
+	struct vhost_iotlb_map *map;
+	phys_addr_t pa;
+
+	spin_lock(&domain->iotlb_lock);
+	map = vhost_iotlb_itree_first(domain->iotlb, (u64)dma_addr,
+				      (u64)dma_addr + size - 1);
+	if (WARN_ON(!map)) {
+		spin_unlock(&domain->iotlb_lock);
+		return;
+	}
+	pa = map->addr;
+	vhost_iotlb_map_free(domain->iotlb, map);
+	spin_unlock(&domain->iotlb_lock);
+
+	vduse_domain_free_iova(iovad, dma_addr, size);
+	free_pages_exact(phys_to_virt(pa), size);
+}
+
+static vm_fault_t vduse_domain_mmap_fault(struct vm_fault *vmf)
+{
+	struct vduse_iova_domain *domain = vmf->vma->vm_private_data;
+	unsigned long iova = vmf->pgoff << PAGE_SHIFT;
+	struct page *page;
+
+	if (!domain)
+		return VM_FAULT_SIGBUS;
+
+	if (iova < domain->bounce_size)
+		page = vduse_domain_alloc_bounce_page(domain, iova);
+	else
+		page = vduse_domain_get_mapping_page(domain, iova);
+
+	if (!page)
+		return VM_FAULT_SIGBUS;
+
+	vmf->page = page;
+
+	return 0;
+}
+
+static const struct vm_operations_struct vduse_domain_mmap_ops = {
+	.fault = vduse_domain_mmap_fault,
+};
+
+static int vduse_domain_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct vduse_iova_domain *domain = file->private_data;
+
+	vma->vm_flags |= VM_DONTDUMP | VM_DONTEXPAND;
+	vma->vm_private_data = domain;
+	vma->vm_ops = &vduse_domain_mmap_ops;
+
+	return 0;
+}
+
+static int vduse_domain_release(struct inode *inode, struct file *file)
+{
+	struct vduse_iova_domain *domain = file->private_data;
+
+	vduse_domain_free_bounce_pages(domain, 0, domain->bounce_size);
+	put_iova_domain(&domain->stream_iovad);
+	put_iova_domain(&domain->consistent_iovad);
+	vhost_iotlb_free(domain->iotlb);
+	vfree(domain->bounce_pages);
+	kfree(domain);
+
+	return 0;
+}
+
+static const struct file_operations vduse_domain_fops = {
+	.mmap = vduse_domain_mmap,
+	.release = vduse_domain_release,
+};
+
+void vduse_domain_destroy(struct vduse_iova_domain *domain)
+{
+	fput(domain->file);
+}
+
+struct vduse_iova_domain *
+vduse_domain_create(unsigned long iova_limit, size_t bounce_size)
+{
+	struct vduse_iova_domain *domain;
+	struct file *file;
+	unsigned long bounce_pfns = PAGE_ALIGN(bounce_size) >> PAGE_SHIFT;
+
+	if (iova_limit <= bounce_size)
+		return NULL;
+
+	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
+	if (!domain)
+		return NULL;
+
+	domain->iotlb = vhost_iotlb_alloc(0, 0);
+	if (!domain->iotlb)
+		goto err_iotlb;
+
+	domain->iova_limit = iova_limit;
+	domain->bounce_size = PAGE_ALIGN(bounce_size);
+	domain->bounce_pages = vzalloc(bounce_pfns * sizeof(struct page *));
+	if (!domain->bounce_pages)
+		goto err_page;
+
+	file = anon_inode_getfile("[vduse-domain]", &vduse_domain_fops,
+				domain, O_RDWR);
+	if (IS_ERR(file))
+		goto err_file;
+
+	domain->file = file;
+	spin_lock_init(&domain->iotlb_lock);
+	init_iova_domain(&domain->stream_iovad,
+			IOVA_ALLOC_SIZE, IOVA_START_PFN);
+	init_iova_domain(&domain->consistent_iovad,
+			PAGE_SIZE, bounce_pfns);
+
+	return domain;
+err_file:
+	vfree(domain->bounce_pages);
+err_page:
+	vhost_iotlb_free(domain->iotlb);
+err_iotlb:
+	kfree(domain);
+	return NULL;
+}
+
+int vduse_domain_init(void)
+{
+	return iova_cache_get();
+}
+
+void vduse_domain_exit(void)
+{
+	iova_cache_put();
+}
diff --git a/drivers/vdpa/vdpa_user/iova_domain.h b/drivers/vdpa/vdpa_user/iova_domain.h
new file mode 100644
index 000000000000..9c85d8346626
--- /dev/null
+++ b/drivers/vdpa/vdpa_user/iova_domain.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * MMU-based IOMMU implementation
+ *
+ * Copyright (C) 2020 Bytedance Inc. and/or its affiliates. All rights reserved.
+ *
+ * Author: Xie Yongji <xieyongji@bytedance.com>
+ *
+ */
+
+#ifndef _VDUSE_IOVA_DOMAIN_H
+#define _VDUSE_IOVA_DOMAIN_H
+
+#include <linux/iova.h>
+#include <linux/dma-mapping.h>
+#include <linux/vhost_iotlb.h>
+
+struct vduse_iova_domain {
+	struct iova_domain stream_iovad;
+	struct iova_domain consistent_iovad;
+	struct page **bounce_pages;
+	size_t bounce_size;
+	unsigned long iova_limit;
+	struct vhost_iotlb *iotlb;
+	spinlock_t iotlb_lock;
+	struct file *file;
+};
+
+static inline struct file *
+vduse_domain_file(struct vduse_iova_domain *domain)
+{
+	return domain->file;
+}
+
+dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain,
+				struct page *page, unsigned long offset,
+				size_t size, enum dma_data_direction dir,
+				unsigned long attrs);
+
+void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
+			dma_addr_t dma_addr, size_t size,
+			enum dma_data_direction dir, unsigned long attrs);
+
+void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
+				size_t size, dma_addr_t *dma_addr,
+				gfp_t flag, unsigned long attrs);
+
+void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
+				void *vaddr, dma_addr_t dma_addr,
+				unsigned long attrs);
+
+void vduse_domain_destroy(struct vduse_iova_domain *domain);
+
+struct vduse_iova_domain *vduse_domain_create(unsigned long iova_limit,
+						size_t bounce_size);
+
+int vduse_domain_init(void);
+
+void vduse_domain_exit(void);
+
+#endif /* _VDUSE_IOVA_DOMAIN_H */
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 07/11] vduse: Introduce VDUSE - vDPA Device in Userspace
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
                   ` (5 preceding siblings ...)
  2021-02-23 11:50 ` [RFC v4 06/11] vduse: Implement an MMU-based IOMMU driver Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 08/11] vduse: Add config interrupt support Xie Yongji
                   ` (3 subsequent siblings)
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

This VDUSE driver enables implementing vDPA devices in userspace.
Both control path and data path of vDPA devices will be able to
be handled in userspace.

In the control path, the VDUSE driver will make use of message
mechnism to forward the config operation from vdpa bus driver
to userspace. Userspace can use read()/write() to receive/reply
those control messages.

In the data path, VDUSE_IOTLB_GET_FD ioctl will be used to get
the file descriptors referring to vDPA device's iova regions. Then
userspace can use mmap() to access those iova regions. Besides,
userspace can use ioctl() to inject interrupt and use the eventfd
mechanism to receive virtqueue kicks.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +
 drivers/vdpa/Kconfig                               |   10 +
 drivers/vdpa/Makefile                              |    1 +
 drivers/vdpa/vdpa_user/Makefile                    |    5 +
 drivers/vdpa/vdpa_user/vduse_dev.c                 | 1348 ++++++++++++++++++++
 include/uapi/linux/vduse.h                         |  136 ++
 6 files changed, 1501 insertions(+)
 create mode 100644 drivers/vdpa/vdpa_user/Makefile
 create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
 create mode 100644 include/uapi/linux/vduse.h

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index a4c75a28c839..71722e6f8f23 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -300,6 +300,7 @@ Code  Seq#    Include File                                           Comments
 'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!
 '|'   00-7F  linux/media.h
 0x80  00-1F  linux/fb.h
+0x81  00-1F  linux/vduse.h
 0x89  00-06  arch/x86/include/asm/sockios.h
 0x89  0B-DF  linux/sockios.h
 0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range
diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
index ffd1e098bfd2..92f07715e3b6 100644
--- a/drivers/vdpa/Kconfig
+++ b/drivers/vdpa/Kconfig
@@ -25,6 +25,16 @@ config VDPA_SIM_NET
 	help
 	  vDPA networking device simulator which loops TX traffic back to RX.
 
+config VDPA_USER
+	tristate "VDUSE (vDPA Device in Userspace) support"
+	depends on EVENTFD && MMU && HAS_DMA
+	select DMA_OPS
+	select VHOST_IOTLB
+	select IOMMU_IOVA
+	help
+	  With VDUSE it is possible to emulate a vDPA Device
+	  in a userspace program.
+
 config IFCVF
 	tristate "Intel IFC VF vDPA driver"
 	depends on PCI_MSI
diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
index d160e9b63a66..66e97778ad03 100644
--- a/drivers/vdpa/Makefile
+++ b/drivers/vdpa/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_VDPA) += vdpa.o
 obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
+obj-$(CONFIG_VDPA_USER) += vdpa_user/
 obj-$(CONFIG_IFCVF)    += ifcvf/
 obj-$(CONFIG_MLX5_VDPA) += mlx5/
diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile
new file mode 100644
index 000000000000..260e0b26af99
--- /dev/null
+++ b/drivers/vdpa/vdpa_user/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+vduse-y := vduse_dev.o iova_domain.o
+
+obj-$(CONFIG_VDPA_USER) += vduse.o
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
new file mode 100644
index 000000000000..393bf99c48be
--- /dev/null
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -0,0 +1,1348 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * VDUSE: vDPA Device in Userspace
+ *
+ * Copyright (C) 2020 Bytedance Inc. and/or its affiliates. All rights reserved.
+ *
+ * Author: Xie Yongji <xieyongji@bytedance.com>
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/eventfd.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/dma-map-ops.h>
+#include <linux/poll.h>
+#include <linux/file.h>
+#include <linux/uio.h>
+#include <linux/vdpa.h>
+#include <uapi/linux/vduse.h>
+#include <uapi/linux/vdpa.h>
+#include <uapi/linux/virtio_config.h>
+#include <linux/mod_devicetable.h>
+
+#include "iova_domain.h"
+
+#define DRV_VERSION  "1.0"
+#define DRV_AUTHOR   "Yongji Xie <xieyongji@bytedance.com>"
+#define DRV_DESC     "vDPA Device in Userspace"
+#define DRV_LICENSE  "GPL v2"
+
+#define VDUSE_DEV_MAX (1U << MINORBITS)
+
+struct vduse_virtqueue {
+	u16 index;
+	bool ready;
+	spinlock_t kick_lock;
+	spinlock_t irq_lock;
+	struct eventfd_ctx *kickfd;
+	struct vdpa_callback cb;
+};
+
+struct vduse_dev;
+
+struct vduse_vdpa {
+	struct vdpa_device vdpa;
+	struct vduse_dev *dev;
+};
+
+struct vduse_dev {
+	struct vduse_vdpa *vdev;
+	struct device dev;
+	struct cdev cdev;
+	struct vduse_virtqueue *vqs;
+	struct vduse_iova_domain *domain;
+	struct vhost_iotlb *iommu;
+	spinlock_t iommu_lock;
+	atomic_t bounce_map;
+	struct mutex msg_lock;
+	atomic64_t msg_unique;
+	wait_queue_head_t waitq;
+	struct list_head send_list;
+	struct list_head recv_list;
+	struct list_head list;
+	bool connected;
+	int minor;
+	u16 vq_size_max;
+	u16 vq_num;
+	u32 vq_align;
+	u32 device_id;
+	u32 vendor_id;
+};
+
+struct vduse_dev_msg {
+	struct vduse_dev_request req;
+	struct vduse_dev_response resp;
+	struct list_head list;
+	wait_queue_head_t waitq;
+	bool completed;
+};
+
+static unsigned long max_bounce_size = (64 * 1024 * 1024);
+module_param(max_bounce_size, ulong, 0444);
+MODULE_PARM_DESC(max_bounce_size, "Maximum bounce buffer size. (default: 64M)");
+
+static unsigned long max_iova_size = (128 * 1024 * 1024);
+module_param(max_iova_size, ulong, 0444);
+MODULE_PARM_DESC(max_iova_size, "Maximum iova space size (default: 128M)");
+
+static DEFINE_MUTEX(vduse_lock);
+static LIST_HEAD(vduse_devs);
+static DEFINE_IDA(vduse_ida);
+
+static dev_t vduse_major;
+static struct class *vduse_class;
+
+static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)
+{
+	struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);
+
+	return vdev->dev;
+}
+
+static inline struct vduse_dev *dev_to_vduse(struct device *dev)
+{
+	struct vdpa_device *vdpa = dev_to_vdpa(dev);
+
+	return vdpa_to_vduse(vdpa);
+}
+
+static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,
+					    uint32_t unique)
+{
+	struct vduse_dev_msg *tmp, *msg = NULL;
+
+	list_for_each_entry(tmp, head, list) {
+		if (tmp->req.unique == unique) {
+			msg = tmp;
+			list_del(&tmp->list);
+			break;
+		}
+	}
+
+	return msg;
+}
+
+static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)
+{
+	struct vduse_dev_msg *msg = NULL;
+
+	if (!list_empty(head)) {
+		msg = list_first_entry(head, struct vduse_dev_msg, list);
+		list_del(&msg->list);
+	}
+
+	return msg;
+}
+
+static void vduse_enqueue_msg(struct list_head *head,
+			      struct vduse_dev_msg *msg)
+{
+	list_add_tail(&msg->list, head);
+}
+
+static int vduse_dev_msg_sync(struct vduse_dev *dev, struct vduse_dev_msg *msg)
+{
+	int ret;
+
+	init_waitqueue_head(&msg->waitq);
+	mutex_lock(&dev->msg_lock);
+	vduse_enqueue_msg(&dev->send_list, msg);
+	wake_up(&dev->waitq);
+	mutex_unlock(&dev->msg_lock);
+	ret = wait_event_interruptible(msg->waitq, msg->completed);
+	mutex_lock(&dev->msg_lock);
+	if (!msg->completed)
+		list_del(&msg->list);
+	else
+		ret = msg->resp.result;
+	mutex_unlock(&dev->msg_lock);
+
+	return ret;
+}
+
+static u64 vduse_dev_get_features(struct vduse_dev *dev)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	msg.req.type = VDUSE_GET_FEATURES;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+
+	return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.features;
+}
+
+static int vduse_dev_set_features(struct vduse_dev *dev, u64 features)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	msg.req.type = VDUSE_SET_FEATURES;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+	msg.req.features = features;
+
+	return vduse_dev_msg_sync(dev, &msg);
+}
+
+static u8 vduse_dev_get_status(struct vduse_dev *dev)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	msg.req.type = VDUSE_GET_STATUS;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+
+	return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.status;
+}
+
+static void vduse_dev_set_status(struct vduse_dev *dev, u8 status)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	msg.req.type = VDUSE_SET_STATUS;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+	msg.req.status = status;
+
+	vduse_dev_msg_sync(dev, &msg);
+}
+
+static void vduse_dev_get_config(struct vduse_dev *dev, unsigned int offset,
+					void *buf, unsigned int len)
+{
+	struct vduse_dev_msg msg = { 0 };
+	unsigned int sz;
+
+	while (len) {
+		sz = min_t(unsigned int, len, sizeof(msg.req.config.data));
+		msg.req.type = VDUSE_GET_CONFIG;
+		msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+		msg.req.config.offset = offset;
+		msg.req.config.len = sz;
+		vduse_dev_msg_sync(dev, &msg);
+		memcpy(buf, msg.resp.config.data, sz);
+		buf += sz;
+		offset += sz;
+		len -= sz;
+	}
+}
+
+static void vduse_dev_set_config(struct vduse_dev *dev, unsigned int offset,
+					const void *buf, unsigned int len)
+{
+	struct vduse_dev_msg msg = { 0 };
+	unsigned int sz;
+
+	while (len) {
+		sz = min_t(unsigned int, len, sizeof(msg.req.config.data));
+		msg.req.type = VDUSE_SET_CONFIG;
+		msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+		msg.req.config.offset = offset;
+		msg.req.config.len = sz;
+		memcpy(msg.req.config.data, buf, sz);
+		vduse_dev_msg_sync(dev, &msg);
+		buf += sz;
+		offset += sz;
+		len -= sz;
+	}
+}
+
+static void vduse_dev_set_vq_num(struct vduse_dev *dev,
+				struct vduse_virtqueue *vq, u32 num)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	msg.req.type = VDUSE_SET_VQ_NUM;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+	msg.req.vq_num.index = vq->index;
+	msg.req.vq_num.num = num;
+
+	vduse_dev_msg_sync(dev, &msg);
+}
+
+static int vduse_dev_set_vq_addr(struct vduse_dev *dev,
+				struct vduse_virtqueue *vq, u64 desc_addr,
+				u64 driver_addr, u64 device_addr)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	msg.req.type = VDUSE_SET_VQ_ADDR;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+	msg.req.vq_addr.index = vq->index;
+	msg.req.vq_addr.desc_addr = desc_addr;
+	msg.req.vq_addr.driver_addr = driver_addr;
+	msg.req.vq_addr.device_addr = device_addr;
+
+	return vduse_dev_msg_sync(dev, &msg);
+}
+
+static void vduse_dev_set_vq_ready(struct vduse_dev *dev,
+				struct vduse_virtqueue *vq, bool ready)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	msg.req.type = VDUSE_SET_VQ_READY;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+	msg.req.vq_ready.index = vq->index;
+	msg.req.vq_ready.ready = ready;
+
+	vduse_dev_msg_sync(dev, &msg);
+}
+
+static bool vduse_dev_get_vq_ready(struct vduse_dev *dev,
+				   struct vduse_virtqueue *vq)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	msg.req.type = VDUSE_GET_VQ_READY;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+	msg.req.vq_ready.index = vq->index;
+
+	return vduse_dev_msg_sync(dev, &msg) ? false : msg.resp.vq_ready.ready;
+}
+
+static int vduse_dev_get_vq_state(struct vduse_dev *dev,
+				struct vduse_virtqueue *vq,
+				struct vdpa_vq_state *state)
+{
+	struct vduse_dev_msg msg = { 0 };
+	int ret;
+
+	msg.req.type = VDUSE_GET_VQ_STATE;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+	msg.req.vq_state.index = vq->index;
+
+	ret = vduse_dev_msg_sync(dev, &msg);
+	if (!ret)
+		state->avail_index = msg.resp.vq_state.avail_idx;
+
+	return ret;
+}
+
+static int vduse_dev_set_vq_state(struct vduse_dev *dev,
+				struct vduse_virtqueue *vq,
+				const struct vdpa_vq_state *state)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	msg.req.type = VDUSE_SET_VQ_STATE;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+	msg.req.vq_state.index = vq->index;
+	msg.req.vq_state.avail_idx = state->avail_index;
+
+	return vduse_dev_msg_sync(dev, &msg);
+}
+
+static int vduse_dev_update_iotlb(struct vduse_dev *dev,
+				u64 start, u64 last)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	if (last < start)
+		return -EINVAL;
+
+	msg.req.type = VDUSE_UPDATE_IOTLB;
+	msg.req.unique = atomic64_fetch_inc(&dev->msg_unique);
+	msg.req.iova.start = start;
+	msg.req.iova.last = last;
+
+	return vduse_dev_msg_sync(dev, &msg);
+}
+
+static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *file = iocb->ki_filp;
+	struct vduse_dev *dev = file->private_data;
+	struct vduse_dev_msg *msg;
+	int size = sizeof(struct vduse_dev_request);
+	ssize_t ret = 0;
+
+	if (iov_iter_count(to) < size)
+		return 0;
+
+	mutex_lock(&dev->msg_lock);
+	while (1) {
+		msg = vduse_dequeue_msg(&dev->send_list);
+		if (msg)
+			break;
+
+		ret = -EAGAIN;
+		if (file->f_flags & O_NONBLOCK)
+			goto unlock;
+
+		mutex_unlock(&dev->msg_lock);
+		ret = wait_event_interruptible_exclusive(dev->waitq,
+					!list_empty(&dev->send_list));
+		if (ret)
+			return ret;
+
+		mutex_lock(&dev->msg_lock);
+	}
+	ret = copy_to_iter(&msg->req, size, to);
+	if (ret != size) {
+		ret = -EFAULT;
+		vduse_enqueue_msg(&dev->send_list, msg);
+		goto unlock;
+	}
+	vduse_enqueue_msg(&dev->recv_list, msg);
+unlock:
+	mutex_unlock(&dev->msg_lock);
+
+	return ret;
+}
+
+static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct vduse_dev *dev = file->private_data;
+	struct vduse_dev_response resp;
+	struct vduse_dev_msg *msg;
+	size_t ret;
+
+	ret = copy_from_iter(&resp, sizeof(resp), from);
+	if (ret != sizeof(resp))
+		return -EINVAL;
+
+	mutex_lock(&dev->msg_lock);
+	msg = vduse_find_msg(&dev->recv_list, resp.request_id);
+	if (!msg) {
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	memcpy(&msg->resp, &resp, sizeof(resp));
+	msg->completed = 1;
+	wake_up(&msg->waitq);
+unlock:
+	mutex_unlock(&dev->msg_lock);
+
+	return ret;
+}
+
+static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)
+{
+	struct vduse_dev *dev = file->private_data;
+	__poll_t mask = 0;
+
+	poll_wait(file, &dev->waitq, wait);
+
+	if (!list_empty(&dev->send_list))
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	return mask;
+}
+
+static int vduse_iotlb_add_range(struct vduse_dev *dev,
+				 u64 start, u64 last,
+				 u64 addr, unsigned int perm,
+				 struct file *file, u64 offset)
+{
+	struct vdpa_map_file *map_file;
+	int ret;
+
+	map_file = kmalloc(sizeof(*map_file), GFP_ATOMIC);
+	if (!map_file)
+		return -ENOMEM;
+
+	map_file->file = get_file(file);
+	map_file->offset = offset;
+
+	spin_lock(&dev->iommu_lock);
+	ret = vhost_iotlb_add_range_ctx(dev->iommu, start, last,
+					addr, perm, map_file);
+	spin_unlock(&dev->iommu_lock);
+	if (ret) {
+		fput(map_file->file);
+		kfree(map_file);
+		return ret;
+	}
+	return 0;
+}
+
+static void vduse_iotlb_del_range(struct vduse_dev *dev, u64 start, u64 last)
+{
+	struct vdpa_map_file *map_file;
+	struct vhost_iotlb_map *map;
+
+	spin_lock(&dev->iommu_lock);
+	while ((map = vhost_iotlb_itree_first(dev->iommu, start, last))) {
+		map_file = (struct vdpa_map_file *)map->opaque;
+		fput(map_file->file);
+		kfree(map_file);
+		vhost_iotlb_map_free(dev->iommu, map);
+	}
+	spin_unlock(&dev->iommu_lock);
+}
+
+static void vduse_dev_reset(struct vduse_dev *dev)
+{
+	int i;
+
+	atomic_set(&dev->bounce_map, 0);
+	vduse_iotlb_del_range(dev, 0ULL, ULLONG_MAX);
+	vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
+
+	for (i = 0; i < dev->vq_num; i++) {
+		struct vduse_virtqueue *vq = &dev->vqs[i];
+
+		spin_lock(&vq->irq_lock);
+		vq->ready = false;
+		vq->cb.callback = NULL;
+		vq->cb.private = NULL;
+		spin_unlock(&vq->irq_lock);
+	}
+}
+
+static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,
+				u64 desc_area, u64 driver_area,
+				u64 device_area)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	return vduse_dev_set_vq_addr(dev, vq, desc_area,
+					driver_area, device_area);
+}
+
+static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	spin_lock(&vq->kick_lock);
+	if (vq->ready && vq->kickfd)
+		eventfd_signal(vq->kickfd, 1);
+	spin_unlock(&vq->kick_lock);
+}
+
+static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
+			      struct vdpa_callback *cb)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	spin_lock(&vq->irq_lock);
+	vq->cb.callback = cb->callback;
+	vq->cb.private = cb->private;
+	spin_unlock(&vq->irq_lock);
+}
+
+static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	vduse_dev_set_vq_num(dev, vq, num);
+}
+
+static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,
+					u16 idx, bool ready)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	vduse_dev_set_vq_ready(dev, vq, ready);
+	vq->ready = ready;
+}
+
+static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	vq->ready = vduse_dev_get_vq_ready(dev, vq);
+
+	return vq->ready;
+}
+
+static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
+				const struct vdpa_vq_state *state)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	return vduse_dev_set_vq_state(dev, vq, state);
+}
+
+static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
+				struct vdpa_vq_state *state)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	return vduse_dev_get_vq_state(dev, vq, state);
+}
+
+static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->vq_align;
+}
+
+static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	u64 fixed = (1ULL << VIRTIO_F_ACCESS_PLATFORM);
+
+	return (vduse_dev_get_features(dev) | fixed);
+}
+
+static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return vduse_dev_set_features(dev, features);
+}
+
+static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
+				  struct vdpa_callback *cb)
+{
+	/* We don't support config interrupt */
+}
+
+static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->vq_size_max;
+}
+
+static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->device_id;
+}
+
+static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->vendor_id;
+}
+
+static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return vduse_dev_get_status(dev);
+}
+
+static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	if (status == 0)
+		vduse_dev_reset(dev);
+
+	vduse_dev_set_status(dev, status);
+}
+
+static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
+			     void *buf, unsigned int len)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	vduse_dev_get_config(dev, offset, buf, len);
+}
+
+static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
+			const void *buf, unsigned int len)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	vduse_dev_set_config(dev, offset, buf, len);
+}
+
+static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
+				struct vhost_iotlb *iotlb)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vhost_iotlb_map *map;
+	struct vdpa_map_file *map_file;
+	u64 start = 0ULL, last = ULLONG_MAX;
+	int ret = 0;
+
+	vduse_iotlb_del_range(dev, start, last);
+
+	for (map = vhost_iotlb_itree_first(iotlb, start, last); map;
+		map = vhost_iotlb_itree_next(map, start, last)) {
+		map_file = (struct vdpa_map_file *)map->opaque;
+		if (!map_file->file)
+			continue;
+
+		ret = vduse_iotlb_add_range(dev, map->start, map->last,
+					    map->addr, map->perm,
+					    map_file->file,
+					    map_file->offset);
+		if (ret)
+			break;
+	}
+	vduse_dev_update_iotlb(dev, start, last);
+
+	return ret;
+}
+
+static void vduse_vdpa_free(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	WARN_ON(!list_empty(&dev->send_list));
+	WARN_ON(!list_empty(&dev->recv_list));
+	dev->vdev = NULL;
+}
+
+static const struct vdpa_config_ops vduse_vdpa_config_ops = {
+	.set_vq_address		= vduse_vdpa_set_vq_address,
+	.kick_vq		= vduse_vdpa_kick_vq,
+	.set_vq_cb		= vduse_vdpa_set_vq_cb,
+	.set_vq_num             = vduse_vdpa_set_vq_num,
+	.set_vq_ready		= vduse_vdpa_set_vq_ready,
+	.get_vq_ready		= vduse_vdpa_get_vq_ready,
+	.set_vq_state		= vduse_vdpa_set_vq_state,
+	.get_vq_state		= vduse_vdpa_get_vq_state,
+	.get_vq_align		= vduse_vdpa_get_vq_align,
+	.get_features		= vduse_vdpa_get_features,
+	.set_features		= vduse_vdpa_set_features,
+	.set_config_cb		= vduse_vdpa_set_config_cb,
+	.get_vq_num_max		= vduse_vdpa_get_vq_num_max,
+	.get_device_id		= vduse_vdpa_get_device_id,
+	.get_vendor_id		= vduse_vdpa_get_vendor_id,
+	.get_status		= vduse_vdpa_get_status,
+	.set_status		= vduse_vdpa_set_status,
+	.get_config		= vduse_vdpa_get_config,
+	.set_config		= vduse_vdpa_set_config,
+	.set_map		= vduse_vdpa_set_map,
+	.free			= vduse_vdpa_free,
+};
+
+static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
+					unsigned long offset, size_t size,
+					enum dma_data_direction dir,
+					unsigned long attrs)
+{
+	struct vduse_dev *vdev = dev_to_vduse(dev);
+	struct vduse_iova_domain *domain = vdev->domain;
+
+	if (atomic_xchg(&vdev->bounce_map, 1) == 0 &&
+		vduse_iotlb_add_range(vdev, 0, domain->bounce_size - 1,
+				      0, VDUSE_ACCESS_RW,
+				      vduse_domain_file(domain), 0)) {
+		atomic_set(&vdev->bounce_map, 0);
+		return DMA_MAPPING_ERROR;
+	}
+
+	return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
+}
+
+static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,
+				size_t size, enum dma_data_direction dir,
+				unsigned long attrs)
+{
+	struct vduse_dev *vdev = dev_to_vduse(dev);
+	struct vduse_iova_domain *domain = vdev->domain;
+
+	return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
+}
+
+static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
+					dma_addr_t *dma_addr, gfp_t flag,
+					unsigned long attrs)
+{
+	struct vduse_dev *vdev = dev_to_vduse(dev);
+	struct vduse_iova_domain *domain = vdev->domain;
+	unsigned long iova;
+	void *addr;
+
+	*dma_addr = DMA_MAPPING_ERROR;
+	addr = vduse_domain_alloc_coherent(domain, size,
+				(dma_addr_t *)&iova, flag, attrs);
+	if (!addr)
+		return NULL;
+
+	if (vduse_iotlb_add_range(vdev, iova, iova + size - 1,
+				  iova, VDUSE_ACCESS_RW,
+				  vduse_domain_file(domain), iova)) {
+		vduse_domain_free_coherent(domain, size, addr, iova, attrs);
+		return NULL;
+	}
+	*dma_addr = (dma_addr_t)iova;
+
+	return addr;
+}
+
+static void vduse_dev_free_coherent(struct device *dev, size_t size,
+					void *vaddr, dma_addr_t dma_addr,
+					unsigned long attrs)
+{
+	struct vduse_dev *vdev = dev_to_vduse(dev);
+	struct vduse_iova_domain *domain = vdev->domain;
+	unsigned long start = (unsigned long)dma_addr;
+	unsigned long last = start + size - 1;
+
+	vduse_iotlb_del_range(vdev, start, last);
+	vduse_dev_update_iotlb(vdev, start, last);
+	vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
+}
+
+static const struct dma_map_ops vduse_dev_dma_ops = {
+	.map_page = vduse_dev_map_page,
+	.unmap_page = vduse_dev_unmap_page,
+	.alloc = vduse_dev_alloc_coherent,
+	.free = vduse_dev_free_coherent,
+};
+
+static unsigned int perm_to_file_flags(u8 perm)
+{
+	unsigned int flags = 0;
+
+	switch (perm) {
+	case VDUSE_ACCESS_WO:
+		flags |= O_WRONLY;
+		break;
+	case VDUSE_ACCESS_RO:
+		flags |= O_RDONLY;
+		break;
+	case VDUSE_ACCESS_RW:
+		flags |= O_RDWR;
+		break;
+	default:
+		WARN(1, "invalidate vhost IOTLB permission\n");
+		break;
+	}
+
+	return flags;
+}
+
+static int vduse_kickfd_setup(struct vduse_dev *dev,
+			struct vduse_vq_eventfd *eventfd)
+{
+	struct eventfd_ctx *ctx = NULL;
+	struct vduse_virtqueue *vq;
+
+	if (eventfd->index >= dev->vq_num)
+		return -EINVAL;
+
+	vq = &dev->vqs[eventfd->index];
+	if (eventfd->fd > 0) {
+		ctx = eventfd_ctx_fdget(eventfd->fd);
+		if (IS_ERR(ctx))
+			return PTR_ERR(ctx);
+	}
+	spin_lock(&vq->kick_lock);
+	if (vq->kickfd)
+		eventfd_ctx_put(vq->kickfd);
+	vq->kickfd = ctx;
+	spin_unlock(&vq->kick_lock);
+
+	return 0;
+}
+
+static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
+			unsigned long arg)
+{
+	struct vduse_dev *dev = file->private_data;
+	void __user *argp = (void __user *)arg;
+	int ret;
+
+	switch (cmd) {
+	case VDUSE_IOTLB_GET_FD: {
+		struct vduse_iotlb_entry entry;
+		struct vhost_iotlb_map *map;
+		struct vdpa_map_file *map_file;
+		struct file *f = NULL;
+
+		ret = -EFAULT;
+		if (copy_from_user(&entry, argp, sizeof(entry)))
+			break;
+
+		spin_lock(&dev->iommu_lock);
+		map = vhost_iotlb_itree_first(dev->iommu, entry.start,
+					      entry.last);
+		if (map) {
+			map_file = (struct vdpa_map_file *)map->opaque;
+			f = get_file(map_file->file);
+			entry.offset = map_file->offset;
+			entry.start = map->start;
+			entry.last = map->last;
+			entry.perm = map->perm;
+		}
+		spin_unlock(&dev->iommu_lock);
+		if (!f) {
+			ret = -EINVAL;
+			break;
+		}
+		if (copy_to_user(argp, &entry, sizeof(entry))) {
+			fput(f);
+			ret = -EFAULT;
+			break;
+		}
+		ret = get_unused_fd_flags(perm_to_file_flags(entry.perm));
+		if (ret < 0) {
+			fput(f);
+			break;
+		}
+		fd_install(ret, f);
+		break;
+	}
+	case VDUSE_VQ_SETUP_KICKFD: {
+		struct vduse_vq_eventfd eventfd;
+
+		ret = -EFAULT;
+		if (copy_from_user(&eventfd, argp, sizeof(eventfd)))
+			break;
+
+		ret = vduse_kickfd_setup(dev, &eventfd);
+		break;
+	}
+	case VDUSE_INJECT_VQ_IRQ: {
+		struct vduse_virtqueue *vq;
+
+		ret = -EINVAL;
+		if (arg >= dev->vq_num)
+			break;
+
+		vq = &dev->vqs[arg];
+		spin_lock_irq(&vq->irq_lock);
+		if (vq->ready && vq->cb.callback) {
+			vq->cb.callback(vq->cb.private);
+			ret = 0;
+		}
+		spin_unlock_irq(&vq->irq_lock);
+		break;
+	}
+	default:
+		ret = -ENOIOCTLCMD;
+		break;
+	}
+
+	return ret;
+}
+
+static int vduse_dev_release(struct inode *inode, struct file *file)
+{
+	struct vduse_dev *dev = file->private_data;
+	struct vduse_dev_msg *msg;
+	int i;
+
+	for (i = 0; i < dev->vq_num; i++) {
+		struct vduse_virtqueue *vq = &dev->vqs[i];
+
+		spin_lock(&vq->kick_lock);
+		if (vq->kickfd)
+			eventfd_ctx_put(vq->kickfd);
+		vq->kickfd = NULL;
+		spin_unlock(&vq->kick_lock);
+	}
+
+	mutex_lock(&dev->msg_lock);
+	while ((msg = vduse_dequeue_msg(&dev->recv_list)))
+		vduse_enqueue_msg(&dev->send_list, msg);
+	mutex_unlock(&dev->msg_lock);
+
+	dev->connected = false;
+
+	return 0;
+}
+
+static int vduse_dev_open(struct inode *inode, struct file *file)
+{
+	struct vduse_dev *dev = container_of(inode->i_cdev,
+					struct vduse_dev, cdev);
+	int ret = -EBUSY;
+
+	mutex_lock(&vduse_lock);
+	if (dev->connected)
+		goto unlock;
+
+	ret = 0;
+	dev->connected = true;
+	file->private_data = dev;
+unlock:
+	mutex_unlock(&vduse_lock);
+
+	return ret;
+}
+
+static const struct file_operations vduse_dev_fops = {
+	.owner		= THIS_MODULE,
+	.open		= vduse_dev_open,
+	.release	= vduse_dev_release,
+	.read_iter	= vduse_dev_read_iter,
+	.write_iter	= vduse_dev_write_iter,
+	.poll		= vduse_dev_poll,
+	.unlocked_ioctl	= vduse_dev_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.llseek		= noop_llseek,
+};
+
+static struct vduse_dev *vduse_dev_create(void)
+{
+	struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+
+	if (!dev)
+		return NULL;
+
+	dev->iommu = vhost_iotlb_alloc(0, 0);
+	if (!dev->iommu) {
+		kfree(dev);
+		return NULL;
+	}
+
+	mutex_init(&dev->msg_lock);
+	INIT_LIST_HEAD(&dev->send_list);
+	INIT_LIST_HEAD(&dev->recv_list);
+	atomic64_set(&dev->msg_unique, 0);
+	spin_lock_init(&dev->iommu_lock);
+	atomic_set(&dev->bounce_map, 0);
+
+	init_waitqueue_head(&dev->waitq);
+
+	return dev;
+}
+
+static void vduse_dev_destroy(struct vduse_dev *dev)
+{
+	vhost_iotlb_free(dev->iommu);
+	mutex_destroy(&dev->msg_lock);
+	kfree(dev);
+}
+
+static struct vduse_dev *vduse_find_dev(const char *name)
+{
+	struct vduse_dev *tmp, *dev = NULL;
+
+	list_for_each_entry(tmp, &vduse_devs, list) {
+		if (!strcmp(dev_name(&tmp->dev), name)) {
+			dev = tmp;
+			break;
+		}
+	}
+	return dev;
+}
+
+static int vduse_destroy_dev(char *name)
+{
+	struct vduse_dev *dev = vduse_find_dev(name);
+
+	if (!dev)
+		return -EINVAL;
+
+	if (dev->vdev || dev->connected)
+		return -EBUSY;
+
+	dev->connected = true;
+	list_del(&dev->list);
+	cdev_device_del(&dev->cdev, &dev->dev);
+	put_device(&dev->dev);
+
+	return 0;
+}
+
+static void vduse_release_dev(struct device *device)
+{
+	struct vduse_dev *dev =
+		container_of(device, struct vduse_dev, dev);
+
+	ida_simple_remove(&vduse_ida, dev->minor);
+	kfree(dev->vqs);
+	vduse_domain_destroy(dev->domain);
+	vduse_dev_destroy(dev);
+	module_put(THIS_MODULE);
+}
+
+static int vduse_create_dev(struct vduse_dev_config *config)
+{
+	int i, ret = -ENOMEM;
+	struct vduse_dev *dev;
+
+	if (config->bounce_size > max_bounce_size)
+		return -EINVAL;
+
+	if (config->bounce_size > max_iova_size)
+		return -EINVAL;
+
+	if (vduse_find_dev(config->name))
+		return -EEXIST;
+
+	dev = vduse_dev_create();
+	if (!dev)
+		return -ENOMEM;
+
+	dev->device_id = config->device_id;
+	dev->vendor_id = config->vendor_id;
+	dev->domain = vduse_domain_create(max_iova_size - 1,
+					config->bounce_size);
+	if (!dev->domain)
+		goto err_domain;
+
+	dev->vq_align = config->vq_align;
+	dev->vq_size_max = config->vq_size_max;
+	dev->vq_num = config->vq_num;
+	dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);
+	if (!dev->vqs)
+		goto err_vqs;
+
+	for (i = 0; i < dev->vq_num; i++) {
+		dev->vqs[i].index = i;
+		spin_lock_init(&dev->vqs[i].kick_lock);
+		spin_lock_init(&dev->vqs[i].irq_lock);
+	}
+
+	ret = ida_simple_get(&vduse_ida, 0, VDUSE_DEV_MAX, GFP_KERNEL);
+	if (ret < 0)
+		goto err_ida;
+
+	dev->minor = ret;
+	device_initialize(&dev->dev);
+	dev->dev.release = vduse_release_dev;
+	dev->dev.class = vduse_class;
+	dev->dev.devt = MKDEV(MAJOR(vduse_major), dev->minor);
+	ret = dev_set_name(&dev->dev, "%s", config->name);
+	if (ret)
+		goto err_name;
+
+	cdev_init(&dev->cdev, &vduse_dev_fops);
+	dev->cdev.owner = THIS_MODULE;
+
+	ret = cdev_device_add(&dev->cdev, &dev->dev);
+	if (ret) {
+		put_device(&dev->dev);
+		return ret;
+	}
+	list_add(&dev->list, &vduse_devs);
+	__module_get(THIS_MODULE);
+
+	return 0;
+err_name:
+	ida_simple_remove(&vduse_ida, dev->minor);
+err_ida:
+	kfree(dev->vqs);
+err_vqs:
+	vduse_domain_destroy(dev->domain);
+err_domain:
+	vduse_dev_destroy(dev);
+	return ret;
+}
+
+static long vduse_ioctl(struct file *file, unsigned int cmd,
+			unsigned long arg)
+{
+	int ret;
+	void __user *argp = (void __user *)arg;
+
+	mutex_lock(&vduse_lock);
+	switch (cmd) {
+	case VDUSE_CREATE_DEV: {
+		struct vduse_dev_config config;
+
+		ret = -EFAULT;
+		if (copy_from_user(&config, argp, sizeof(config)))
+			break;
+
+		ret = vduse_create_dev(&config);
+		break;
+	}
+	case VDUSE_DESTROY_DEV: {
+		char name[VDUSE_NAME_MAX];
+
+		ret = -EFAULT;
+		if (copy_from_user(name, argp, VDUSE_NAME_MAX))
+			break;
+
+		ret = vduse_destroy_dev(name);
+		break;
+	}
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	mutex_unlock(&vduse_lock);
+
+	return ret;
+}
+
+static const struct file_operations vduse_fops = {
+	.owner		= THIS_MODULE,
+	.unlocked_ioctl	= vduse_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.llseek		= noop_llseek,
+};
+
+static char *vduse_devnode(struct device *dev, umode_t *mode)
+{
+	return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));
+}
+
+static struct miscdevice vduse_misc = {
+	.fops = &vduse_fops,
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "vduse",
+	.nodename = "vduse/control",
+};
+
+static void vduse_mgmtdev_release(struct device *dev)
+{
+}
+
+static struct device vduse_mgmtdev = {
+	.init_name = "vduse",
+	.release = vduse_mgmtdev_release,
+};
+
+static struct vdpa_mgmt_dev mgmt_dev;
+
+static int vduse_dev_add_vdpa(struct vduse_dev *dev, const char *name)
+{
+	struct vduse_vdpa *vdev = dev->vdev;
+	int ret;
+
+	if (vdev)
+		return -EEXIST;
+
+	vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, NULL,
+				 &vduse_vdpa_config_ops,
+				 dev->vq_num, name, true);
+	if (!vdev)
+		return -ENOMEM;
+
+	vdev->dev = dev;
+	vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;
+	ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));
+	if (ret)
+		goto err;
+
+	set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);
+	vdev->vdpa.dma_dev = &vdev->vdpa.dev;
+	vdev->vdpa.mdev = &mgmt_dev;
+
+	ret = _vdpa_register_device(&vdev->vdpa);
+	if (ret)
+		goto err;
+
+	dev->vdev = vdev;
+
+	return 0;
+err:
+	put_device(&vdev->vdpa.dev);
+	return ret;
+}
+
+static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
+{
+	struct vduse_dev *dev;
+	int ret = -EINVAL;
+
+	mutex_lock(&vduse_lock);
+	dev = vduse_find_dev(name);
+	if (!dev)
+		goto unlock;
+
+	ret = vduse_dev_add_vdpa(dev, name);
+unlock:
+	mutex_unlock(&vduse_lock);
+
+	return ret;
+}
+
+static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)
+{
+	_vdpa_unregister_device(dev);
+}
+
+static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {
+	.dev_add = vdpa_dev_add,
+	.dev_del = vdpa_dev_del,
+};
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_DEV_ANY_ID, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct vdpa_mgmt_dev mgmt_dev = {
+	.device = &vduse_mgmtdev,
+	.id_table = id_table,
+	.ops = &vdpa_dev_mgmtdev_ops,
+};
+
+static int vduse_mgmtdev_init(void)
+{
+	int ret;
+
+	ret = device_register(&vduse_mgmtdev);
+	if (ret)
+		return ret;
+
+	ret = vdpa_mgmtdev_register(&mgmt_dev);
+	if (ret)
+		goto err;
+
+	return 0;
+err:
+	device_unregister(&vduse_mgmtdev);
+	return ret;
+}
+
+static void vduse_mgmtdev_exit(void)
+{
+	vdpa_mgmtdev_unregister(&mgmt_dev);
+	device_unregister(&vduse_mgmtdev);
+}
+
+static int vduse_init(void)
+{
+	int ret;
+
+	ret = misc_register(&vduse_misc);
+	if (ret)
+		return ret;
+
+	vduse_class = class_create(THIS_MODULE, "vduse");
+	if (IS_ERR(vduse_class)) {
+		ret = PTR_ERR(vduse_class);
+		goto err_class;
+	}
+	vduse_class->devnode = vduse_devnode;
+
+	ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");
+	if (ret)
+		goto err_chardev;
+
+	ret = vduse_domain_init();
+	if (ret)
+		goto err_domain;
+
+	ret = vduse_mgmtdev_init();
+	if (ret)
+		goto err_mgmtdev;
+
+	return 0;
+err_mgmtdev:
+	vduse_domain_exit();
+err_domain:
+	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
+err_chardev:
+	class_destroy(vduse_class);
+err_class:
+	misc_deregister(&vduse_misc);
+	return ret;
+}
+module_init(vduse_init);
+
+static void vduse_exit(void)
+{
+	misc_deregister(&vduse_misc);
+	class_destroy(vduse_class);
+	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
+	vduse_domain_exit();
+	vduse_mgmtdev_exit();
+}
+module_exit(vduse_exit);
+
+MODULE_VERSION(DRV_VERSION);
+MODULE_LICENSE(DRV_LICENSE);
+MODULE_AUTHOR(DRV_AUTHOR);
+MODULE_DESCRIPTION(DRV_DESC);
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
new file mode 100644
index 000000000000..9391c4acfa53
--- /dev/null
+++ b/include/uapi/linux/vduse.h
@@ -0,0 +1,136 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_VDUSE_H_
+#define _UAPI_VDUSE_H_
+
+#include <linux/types.h>
+
+#define VDUSE_CONFIG_DATA_LEN	256
+#define VDUSE_NAME_MAX	256
+
+/* the control messages definition for read/write */
+
+enum vduse_req_type {
+	VDUSE_SET_VQ_NUM,
+	VDUSE_SET_VQ_ADDR,
+	VDUSE_SET_VQ_READY,
+	VDUSE_GET_VQ_READY,
+	VDUSE_SET_VQ_STATE,
+	VDUSE_GET_VQ_STATE,
+	VDUSE_SET_FEATURES,
+	VDUSE_GET_FEATURES,
+	VDUSE_SET_STATUS,
+	VDUSE_GET_STATUS,
+	VDUSE_SET_CONFIG,
+	VDUSE_GET_CONFIG,
+	VDUSE_UPDATE_IOTLB,
+};
+
+struct vduse_vq_num {
+	__u32 index;
+	__u32 num;
+};
+
+struct vduse_vq_addr {
+	__u32 index;
+	__u64 desc_addr;
+	__u64 driver_addr;
+	__u64 device_addr;
+};
+
+struct vduse_vq_ready {
+	__u32 index;
+	__u8 ready;
+};
+
+struct vduse_vq_state {
+	__u32 index;
+	__u16 avail_idx;
+};
+
+struct vduse_dev_config_data {
+	__u32 offset;
+	__u32 len;
+	__u8 data[VDUSE_CONFIG_DATA_LEN];
+};
+
+struct vduse_iova_range {
+	__u64 start;
+	__u64 last;
+};
+
+struct vduse_dev_request {
+	__u32 type; /* request type */
+	__u32 unique; /* request id */
+	__u32 reserved[2]; /* for feature use */
+	union {
+		struct vduse_vq_num vq_num; /* virtqueue num */
+		struct vduse_vq_addr vq_addr; /* virtqueue address */
+		struct vduse_vq_ready vq_ready; /* virtqueue ready status */
+		struct vduse_vq_state vq_state; /* virtqueue state */
+		struct vduse_dev_config_data config; /* virtio device config space */
+		struct vduse_iova_range iova; /* iova range for updating */
+		__u64 features; /* virtio features */
+		__u8 status; /* device status */
+	};
+};
+
+struct vduse_dev_response {
+	__u32 request_id; /* corresponding request id */
+#define VDUSE_REQUEST_OK	0x00
+#define VDUSE_REQUEST_FAILED	0x01
+	__u8 result; /* the result of request */
+	__u8 reserved[11]; /* for feature use */
+	union {
+		struct vduse_vq_ready vq_ready; /* virtqueue ready status */
+		struct vduse_vq_state vq_state; /* virtqueue state */
+		struct vduse_dev_config_data config; /* virtio device config space */
+		__u64 features; /* virtio features */
+		__u8 status; /* device status */
+	};
+};
+
+/* ioctls */
+
+struct vduse_dev_config {
+	char name[VDUSE_NAME_MAX]; /* vduse device name */
+	__u32 vendor_id; /* virtio vendor id */
+	__u32 device_id; /* virtio device id */
+	__u64 bounce_size; /* bounce buffer size for iommu */
+	__u16 vq_num; /* the number of virtqueues */
+	__u16 vq_size_max; /* the max size of virtqueue */
+	__u32 vq_align; /* the allocation alignment of virtqueue's metadata */
+};
+
+struct vduse_iotlb_entry {
+	__u64 offset; /* the mmap offset on fd */
+	__u64 start; /* start of the IOVA range */
+	__u64 last; /* last of the IOVA range */
+#define VDUSE_ACCESS_RO 0x1
+#define VDUSE_ACCESS_WO 0x2
+#define VDUSE_ACCESS_RW 0x3
+	__u8 perm; /* access permission of this range */
+};
+
+struct vduse_vq_eventfd {
+	__u32 index; /* virtqueue index */
+	int fd; /* eventfd, -1 means de-assigning the eventfd */
+};
+
+#define VDUSE_BASE	0x81
+
+/* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */
+#define VDUSE_CREATE_DEV	_IOW(VDUSE_BASE, 0x01, struct vduse_dev_config)
+
+/* Destroy a vduse device. Make sure there are no references to the char device */
+#define VDUSE_DESTROY_DEV	_IOW(VDUSE_BASE, 0x02, char[VDUSE_NAME_MAX])
+
+/* Get a file descriptor for the mmap'able iova region */
+#define VDUSE_IOTLB_GET_FD	_IOWR(VDUSE_BASE, 0x03, struct vduse_iotlb_entry)
+
+/* Setup an eventfd to receive kick for virtqueue */
+#define VDUSE_VQ_SETUP_KICKFD	_IOW(VDUSE_BASE, 0x04, struct vduse_vq_eventfd)
+
+/* Inject an interrupt for specific virtqueue */
+#define VDUSE_INJECT_VQ_IRQ	_IO(VDUSE_BASE, 0x05)
+
+#endif /* _UAPI_VDUSE_H_ */
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 08/11] vduse: Add config interrupt support
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
                   ` (6 preceding siblings ...)
  2021-02-23 11:50 ` [RFC v4 07/11] vduse: Introduce VDUSE - vDPA Device in Userspace Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 09/11] Documentation: Add documentation for VDUSE Xie Yongji
                   ` (2 subsequent siblings)
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

This patch introduces a new ioctl VDUSE_INJECT_CONFIG_IRQ
to support injecting config interrupt.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 24 +++++++++++++++++++++++-
 include/uapi/linux/vduse.h         |  3 +++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 393bf99c48be..8042d3fa57f1 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -66,6 +66,8 @@ struct vduse_dev {
 	struct list_head send_list;
 	struct list_head recv_list;
 	struct list_head list;
+	struct vdpa_callback config_cb;
+	spinlock_t irq_lock;
 	bool connected;
 	int minor;
 	u16 vq_size_max;
@@ -483,6 +485,11 @@ static void vduse_dev_reset(struct vduse_dev *dev)
 	vduse_iotlb_del_range(dev, 0ULL, ULLONG_MAX);
 	vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
 
+	spin_lock(&dev->irq_lock);
+	dev->config_cb.callback = NULL;
+	dev->config_cb.private = NULL;
+	spin_unlock(&dev->irq_lock);
+
 	for (i = 0; i < dev->vq_num; i++) {
 		struct vduse_virtqueue *vq = &dev->vqs[i];
 
@@ -599,7 +606,12 @@ static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
 static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
 				  struct vdpa_callback *cb)
 {
-	/* We don't support config interrupt */
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	spin_lock(&dev->irq_lock);
+	dev->config_cb.callback = cb->callback;
+	dev->config_cb.private = cb->private;
+	spin_unlock(&dev->irq_lock);
 }
 
 static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
@@ -913,6 +925,15 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		spin_unlock_irq(&vq->irq_lock);
 		break;
 	}
+	case VDUSE_INJECT_CONFIG_IRQ:
+		ret = -EINVAL;
+		spin_lock_irq(&dev->irq_lock);
+		if (dev->config_cb.callback) {
+			dev->config_cb.callback(dev->config_cb.private);
+			ret = 0;
+		}
+		spin_unlock_irq(&dev->irq_lock);
+		break;
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
@@ -996,6 +1017,7 @@ static struct vduse_dev *vduse_dev_create(void)
 	INIT_LIST_HEAD(&dev->recv_list);
 	atomic64_set(&dev->msg_unique, 0);
 	spin_lock_init(&dev->iommu_lock);
+	spin_lock_init(&dev->irq_lock);
 	atomic_set(&dev->bounce_map, 0);
 
 	init_waitqueue_head(&dev->waitq);
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index 9391c4acfa53..9070cd512cb4 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -133,4 +133,7 @@ struct vduse_vq_eventfd {
 /* Inject an interrupt for specific virtqueue */
 #define VDUSE_INJECT_VQ_IRQ	_IO(VDUSE_BASE, 0x05)
 
+/* Inject a config interrupt */
+#define VDUSE_INJECT_CONFIG_IRQ	_IO(VDUSE_BASE, 0x06)
+
 #endif /* _UAPI_VDUSE_H_ */
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 09/11] Documentation: Add documentation for VDUSE
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
                   ` (7 preceding siblings ...)
  2021-02-23 11:50 ` [RFC v4 08/11] vduse: Add config interrupt support Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 10/11] vduse: Introduce a workqueue for irq injection Xie Yongji
  2021-02-23 11:50 ` [RFC v4 11/11] vduse: Support binding irq to the specified cpu Xie Yongji
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

VDUSE (vDPA Device in Userspace) is a framework to support
implementing software-emulated vDPA devices in userspace. This
document is intended to clarify the VDUSE design and usage.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 Documentation/userspace-api/index.rst |   1 +
 Documentation/userspace-api/vduse.rst | 112 ++++++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)
 create mode 100644 Documentation/userspace-api/vduse.rst

diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst
index acd2cc2a538d..f63119130898 100644
--- a/Documentation/userspace-api/index.rst
+++ b/Documentation/userspace-api/index.rst
@@ -24,6 +24,7 @@ place where this information is gathered.
    ioctl/index
    iommu
    media/index
+   vduse
 
 .. only::  subproject and html
 
diff --git a/Documentation/userspace-api/vduse.rst b/Documentation/userspace-api/vduse.rst
new file mode 100644
index 000000000000..2a20e686bb59
--- /dev/null
+++ b/Documentation/userspace-api/vduse.rst
@@ -0,0 +1,112 @@
+==================================
+VDUSE - "vDPA Device in Userspace"
+==================================
+
+vDPA (virtio data path acceleration) device is a device that uses a
+datapath which complies with the virtio specifications with vendor
+specific control path. vDPA devices can be both physically located on
+the hardware or emulated by software. VDUSE is a framework that makes it
+possible to implement software-emulated vDPA devices in userspace.
+
+How VDUSE works
+------------
+Each userspace vDPA device is created by the VDUSE_CREATE_DEV ioctl on
+the character device (/dev/vduse/control). Then a device file with the
+specified name (/dev/vduse/$NAME) will appear, which can be used to
+implement the userspace vDPA device's control path and data path.
+
+To implement control path, a message-based communication protocol and some
+types of control messages are introduced in the VDUSE framework:
+
+- VDUSE_SET_VQ_ADDR: Set the vring address of virtqueue.
+
+- VDUSE_SET_VQ_NUM: Set the size of virtqueue
+
+- VDUSE_SET_VQ_READY: Set ready status of virtqueue
+
+- VDUSE_GET_VQ_READY: Get ready status of virtqueue
+
+- VDUSE_SET_VQ_STATE: Set the state for virtqueue
+
+- VDUSE_GET_VQ_STATE: Get the state for virtqueue
+
+- VDUSE_SET_FEATURES: Set virtio features supported by the driver
+
+- VDUSE_GET_FEATURES: Get virtio features supported by the device
+
+- VDUSE_SET_STATUS: Set the device status
+
+- VDUSE_GET_STATUS: Get the device status
+
+- VDUSE_SET_CONFIG: Write to device specific configuration space
+
+- VDUSE_GET_CONFIG: Read from device specific configuration space
+
+- VDUSE_UPDATE_IOTLB: Notify userspace to update the memory mapping in device IOTLB
+
+Those control messages are mostly based on the vdpa_config_ops in
+include/linux/vdpa.h which defines a unified interface to control
+different types of vdpa device. Userspace needs to read()/write()
+on the VDUSE device file to receive/reply those control messages
+from/to VDUSE kernel module as follows:
+
+.. code-block:: c
+
+	static int vduse_message_handler(int dev_fd)
+	{
+		int len;
+		struct vduse_dev_request req;
+		struct vduse_dev_response resp;
+
+		len = read(dev_fd, &req, sizeof(req));
+		if (len != sizeof(req))
+			return -1;
+
+		resp.request_id = req.unique;
+
+		switch (req.type) {
+
+		/* handle different types of message */
+
+		}
+
+		len = write(dev_fd, &resp, sizeof(resp));
+		if (len != sizeof(resp))
+			return -1;
+
+		return 0;
+	}
+
+In the deta path, vDPA device's iova regions will be mapped into userspace
+with the help of VDUSE_IOTLB_GET_FD ioctl on the VDUSE device file:
+
+- VDUSE_IOTLB_GET_FD: get the file descriptor to iova region. Userspace can
+  access this iova region by passing the fd to mmap().
+
+Besides, the following ioctls on the VDUSE device file are provided to support
+interrupt injection and setting up eventfd for virtqueue kicks:
+
+- VDUSE_VQ_SETUP_KICKFD: set the kickfd for virtqueue, this eventfd is used
+  by VDUSE kernel module to notify userspace to consume the vring.
+
+- VDUSE_INJECT_VQ_IRQ: inject an interrupt for specific virtqueue
+
+- VDUSE_INJECT_CONFIG_IRQ: inject a config interrupt
+
+MMU-based IOMMU Driver
+----------------------
+In virtio-vdpa case, VDUSE framework implements an MMU-based on-chip IOMMU
+driver to support mapping the kernel DMA buffer into the userspace iova
+region dynamically.
+
+The basic idea behind this driver is treating MMU (VA->PA) as IOMMU (IOVA->PA).
+The driver will set up MMU mapping instead of IOMMU mapping for the DMA transfer
+so that the userspace process is able to use its virtual address to access
+the DMA buffer in kernel.
+
+And to avoid security issue, a bounce-buffering mechanism is introduced to
+prevent userspace accessing the original buffer directly which may contain other
+kernel data. During the mapping, unmapping, the driver will copy the data from
+the original buffer to the bounce buffer and back, depending on the direction of
+the transfer. And the bounce-buffer addresses will be mapped into the user address
+space instead of the original one.
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 10/11] vduse: Introduce a workqueue for irq injection
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
                   ` (8 preceding siblings ...)
  2021-02-23 11:50 ` [RFC v4 09/11] Documentation: Add documentation for VDUSE Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  2021-02-23 11:50 ` [RFC v4 11/11] vduse: Support binding irq to the specified cpu Xie Yongji
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

This patch introduces a workqueue to support injecting
virtqueue's interrupt asynchronously. This is mainly
for performance considerations which makes sure the push()
and pop() for used vring can be asynchronous.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 8042d3fa57f1..f5adeb9ee027 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -42,6 +42,7 @@ struct vduse_virtqueue {
 	spinlock_t irq_lock;
 	struct eventfd_ctx *kickfd;
 	struct vdpa_callback cb;
+	struct work_struct inject;
 };
 
 struct vduse_dev;
@@ -99,6 +100,7 @@ static DEFINE_IDA(vduse_ida);
 
 static dev_t vduse_major;
 static struct class *vduse_class;
+static struct workqueue_struct *vduse_irq_wq;
 
 static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)
 {
@@ -852,6 +854,17 @@ static int vduse_kickfd_setup(struct vduse_dev *dev,
 	return 0;
 }
 
+static void vduse_vq_irq_inject(struct work_struct *work)
+{
+	struct vduse_virtqueue *vq = container_of(work,
+					struct vduse_virtqueue, inject);
+
+	spin_lock_irq(&vq->irq_lock);
+	if (vq->ready && vq->cb.callback)
+		vq->cb.callback(vq->cb.private);
+	spin_unlock_irq(&vq->irq_lock);
+}
+
 static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 			unsigned long arg)
 {
@@ -917,12 +930,7 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 			break;
 
 		vq = &dev->vqs[arg];
-		spin_lock_irq(&vq->irq_lock);
-		if (vq->ready && vq->cb.callback) {
-			vq->cb.callback(vq->cb.private);
-			ret = 0;
-		}
-		spin_unlock_irq(&vq->irq_lock);
+		queue_work(vduse_irq_wq, &vq->inject);
 		break;
 	}
 	case VDUSE_INJECT_CONFIG_IRQ:
@@ -1109,6 +1117,7 @@ static int vduse_create_dev(struct vduse_dev_config *config)
 
 	for (i = 0; i < dev->vq_num; i++) {
 		dev->vqs[i].index = i;
+		INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);
 		spin_lock_init(&dev->vqs[i].kick_lock);
 		spin_lock_init(&dev->vqs[i].irq_lock);
 	}
@@ -1333,6 +1342,11 @@ static int vduse_init(void)
 	if (ret)
 		goto err_chardev;
 
+	vduse_irq_wq = alloc_workqueue("vduse-irq",
+				WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);
+	if (!vduse_irq_wq)
+		goto err_wq;
+
 	ret = vduse_domain_init();
 	if (ret)
 		goto err_domain;
@@ -1344,6 +1358,8 @@ static int vduse_init(void)
 	return 0;
 err_mgmtdev:
 	vduse_domain_exit();
+err_wq:
+	destroy_workqueue(vduse_irq_wq);
 err_domain:
 	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
 err_chardev:
@@ -1359,6 +1375,7 @@ static void vduse_exit(void)
 	misc_deregister(&vduse_misc);
 	class_destroy(vduse_class);
 	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
+	destroy_workqueue(vduse_irq_wq);
 	vduse_domain_exit();
 	vduse_mgmtdev_exit();
 }
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [RFC v4 11/11] vduse: Support binding irq to the specified cpu
  2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
                   ` (9 preceding siblings ...)
  2021-02-23 11:50 ` [RFC v4 10/11] vduse: Introduce a workqueue for irq injection Xie Yongji
@ 2021-02-23 11:50 ` Xie Yongji
  10 siblings, 0 replies; 12+ messages in thread
From: Xie Yongji @ 2021-02-23 11:50 UTC (permalink / raw)
  To: mst, jasowang, stefanha, sgarzare, parav, bob.liu, hch, rdunlap,
	willy, viro, axboe, bcrl, corbet
  Cc: virtualization, netdev, kvm, linux-aio, linux-fsdevel

Add a parameter for the ioctl VDUSE_INJECT_VQ_IRQ to support
injecting virtqueue's interrupt to the specified cpu.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 22 +++++++++++++++++-----
 include/uapi/linux/vduse.h         |  7 ++++++-
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index f5adeb9ee027..df3d467fff40 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -923,14 +923,27 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		break;
 	}
 	case VDUSE_INJECT_VQ_IRQ: {
+		struct vduse_vq_irq irq;
 		struct vduse_virtqueue *vq;
 
+		ret = -EFAULT;
+		if (copy_from_user(&irq, argp, sizeof(irq)))
+			break;
+
 		ret = -EINVAL;
-		if (arg >= dev->vq_num)
+		if (irq.index >= dev->vq_num)
+			break;
+
+		if (irq.cpu != -1 && (irq.cpu >= nr_cpu_ids ||
+		    !cpu_online(irq.cpu)))
 			break;
 
-		vq = &dev->vqs[arg];
-		queue_work(vduse_irq_wq, &vq->inject);
+		ret = 0;
+		vq = &dev->vqs[irq.index];
+		if (irq.cpu == -1)
+			queue_work(vduse_irq_wq, &vq->inject);
+		else
+			queue_work_on(irq.cpu, vduse_irq_wq, &vq->inject);
 		break;
 	}
 	case VDUSE_INJECT_CONFIG_IRQ:
@@ -1342,8 +1355,7 @@ static int vduse_init(void)
 	if (ret)
 		goto err_chardev;
 
-	vduse_irq_wq = alloc_workqueue("vduse-irq",
-				WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);
+	vduse_irq_wq = alloc_workqueue("vduse-irq", WQ_HIGHPRI, 0);
 	if (!vduse_irq_wq)
 		goto err_wq;
 
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index 9070cd512cb4..9c70fd842ce5 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -116,6 +116,11 @@ struct vduse_vq_eventfd {
 	int fd; /* eventfd, -1 means de-assigning the eventfd */
 };
 
+struct vduse_vq_irq {
+	__u32 index; /* virtqueue index */
+	int cpu; /* bind irq to the specified cpu, -1 means running on the current cpu */
+};
+
 #define VDUSE_BASE	0x81
 
 /* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */
@@ -131,7 +136,7 @@ struct vduse_vq_eventfd {
 #define VDUSE_VQ_SETUP_KICKFD	_IOW(VDUSE_BASE, 0x04, struct vduse_vq_eventfd)
 
 /* Inject an interrupt for specific virtqueue */
-#define VDUSE_INJECT_VQ_IRQ	_IO(VDUSE_BASE, 0x05)
+#define VDUSE_INJECT_VQ_IRQ	_IOW(VDUSE_BASE, 0x05, struct vduse_vq_irq)
 
 /* Inject a config interrupt */
 #define VDUSE_INJECT_CONFIG_IRQ	_IO(VDUSE_BASE, 0x06)
-- 
2.11.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, back to index

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-23 11:50 [RFC v4 00/11] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
2021-02-23 11:50 ` [RFC v4 01/11] eventfd: Increase the recursion depth of eventfd_signal() Xie Yongji
2021-02-23 11:50 ` [RFC v4 02/11] vhost-vdpa: protect concurrent access to vhost device iotlb Xie Yongji
2021-02-23 11:50 ` [RFC v4 03/11] vhost-iotlb: Add an opaque pointer for vhost IOTLB Xie Yongji
2021-02-23 11:50 ` [RFC v4 04/11] vdpa: Add an opaque pointer for vdpa_config_ops.dma_map() Xie Yongji
2021-02-23 11:50 ` [RFC v4 05/11] vdpa: Support transferring virtual addressing during DMA mapping Xie Yongji
2021-02-23 11:50 ` [RFC v4 06/11] vduse: Implement an MMU-based IOMMU driver Xie Yongji
2021-02-23 11:50 ` [RFC v4 07/11] vduse: Introduce VDUSE - vDPA Device in Userspace Xie Yongji
2021-02-23 11:50 ` [RFC v4 08/11] vduse: Add config interrupt support Xie Yongji
2021-02-23 11:50 ` [RFC v4 09/11] Documentation: Add documentation for VDUSE Xie Yongji
2021-02-23 11:50 ` [RFC v4 10/11] vduse: Introduce a workqueue for irq injection Xie Yongji
2021-02-23 11:50 ` [RFC v4 11/11] vduse: Support binding irq to the specified cpu Xie Yongji

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