[PATCH v2 0/3] vdpa: add two ioctl commands to support generic vDPA

[PATCH v2 0/3] vdpa: add two ioctl commands to support generic vDPA

[Longpeng(Mike)]

From: Longpeng <longpeng2@huawei.com>

To support generic vdpa deivce[1], we need add the following ioctls:
  - GET_CONFIG_SIZE: the size of the virtio config space (Patch 1)
  - GET_VQS_COUNT: the count of virtqueues that exposed (Patch 2)

Changes v2 -> v3:
  Patch 2:
    - use a separate patch for the u32 converting. [Jason]

Changes v1(RFC) -> v2:
  Patch 1:
    - be more verbose in commit message and the comment for get_config_size
      [Jason]
  Patch 2:
    - change the type of nvqs to u32 [Jason]
  Patch 3:
    - drop from this series because Gautam sent another proposal[2]

[1] https://lore.kernel.org/all/20220105005900.860-1-longpeng2@huawei.com/
[2] https://patchwork.kernel.org/project/kvm/patch/20220224212314.1326-20-gdawar@xilinx.com/

Longpeng (3):
  vdpa: support exposing the config size to userspace
  vdpa: change the type of nvqs to u32
  vdpa: support exposing the count of vqs to userspace

 drivers/vdpa/vdpa.c        |  6 +++---
 drivers/vhost/vdpa.c       | 40 ++++++++++++++++++++++++++++++++++++----
 include/linux/vdpa.h       |  9 +++++----
 include/uapi/linux/vhost.h |  7 +++++++
 4 files changed, 51 insertions(+), 11 deletions(-)

-- 
1.8.3.1

[PATCH v2 1/3] vdpa: support exposing the config size to userspace

[Longpeng(Mike)]

From: Longpeng <longpeng2@huawei.com>

- GET_CONFIG_SIZE: return the size of the virtio config space.

The size contains the fields which are conditional on feature
bits.

Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Longpeng <longpeng2@huawei.com>
---
 drivers/vhost/vdpa.c       | 17 +++++++++++++++++
 include/linux/vdpa.h       |  3 ++-
 include/uapi/linux/vhost.h |  4 ++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index ec5249e..605c7ae 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -355,6 +355,20 @@ static long vhost_vdpa_get_iova_range(struct vhost_vdpa *v, u32 __user *argp)
 	return 0;
 }
 
+static long vhost_vdpa_get_config_size(struct vhost_vdpa *v, u32 __user *argp)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	u32 size;
+
+	size = ops->get_config_size(vdpa);
+
+	if (copy_to_user(argp, &size, sizeof(size)))
+		return -EFAULT;
+
+	return 0;
+}
+
 static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 				   void __user *argp)
 {
@@ -492,6 +506,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
 	case VHOST_VDPA_GET_IOVA_RANGE:
 		r = vhost_vdpa_get_iova_range(v, argp);
 		break;
+	case VHOST_VDPA_GET_CONFIG_SIZE:
+		r = vhost_vdpa_get_config_size(v, argp);
+		break;
 	default:
 		r = vhost_dev_ioctl(&v->vdev, cmd, argp);
 		if (r == -ENOIOCTLCMD)
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 721089b..a526919 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -207,7 +207,8 @@ struct vdpa_map_file {
  * @reset:			Reset device
  *				@vdev: vdpa device
  *				Returns integer: success (0) or error (< 0)
- * @get_config_size:		Get the size of the configuration space
+ * @get_config_size:		Get the size of the configuration space includes
+ *				fields that are conditional on feature bits.
  *				@vdev: vdpa device
  *				Returns size_t: configuration size
  * @get_config:			Read from device specific configuration space
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index c998860..bc74e95 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -150,4 +150,8 @@
 /* Get the valid iova range */
 #define VHOST_VDPA_GET_IOVA_RANGE	_IOR(VHOST_VIRTIO, 0x78, \
 					     struct vhost_vdpa_iova_range)
+
+/* Get the config size */
+#define VHOST_VDPA_GET_CONFIG_SIZE	_IOR(VHOST_VIRTIO, 0x79, __u32)
+
 #endif
-- 
1.8.3.1

[PATCH v2 2/3] vdpa: change the type of nvqs to u32

[Longpeng(Mike)]

From: Longpeng <longpeng2@huawei.com>

Change vdpa_device.nvqs and vhost_vdpa.nvqs to use u32

Signed-off-by: Longpeng <longpeng2@huawei.com>
---
 drivers/vdpa/vdpa.c  |  6 +++---
 drivers/vhost/vdpa.c | 10 ++++++----
 include/linux/vdpa.h |  6 +++---
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 1ea5254..2b75c00 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -232,7 +232,7 @@ static int vdpa_name_match(struct device *dev, const void *data)
 	return (strcmp(dev_name(&vdev->dev), data) == 0);
 }
 
-static int __vdpa_register_device(struct vdpa_device *vdev, int nvqs)
+static int __vdpa_register_device(struct vdpa_device *vdev, u32 nvqs)
 {
 	struct device *dev;
 
@@ -257,7 +257,7 @@ static int __vdpa_register_device(struct vdpa_device *vdev, int nvqs)
  *
  * Return: Returns an error when fail to add device to vDPA bus
  */
-int _vdpa_register_device(struct vdpa_device *vdev, int nvqs)
+int _vdpa_register_device(struct vdpa_device *vdev, u32 nvqs)
 {
 	if (!vdev->mdev)
 		return -EINVAL;
@@ -274,7 +274,7 @@ int _vdpa_register_device(struct vdpa_device *vdev, int nvqs)
  *
  * Return: Returns an error when fail to add to vDPA bus
  */
-int vdpa_register_device(struct vdpa_device *vdev, int nvqs)
+int vdpa_register_device(struct vdpa_device *vdev, u32 nvqs)
 {
 	int err;
 
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 605c7ae..0c82eb5 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -42,7 +42,7 @@ struct vhost_vdpa {
 	struct device dev;
 	struct cdev cdev;
 	atomic_t opened;
-	int nvqs;
+	u32 nvqs;
 	int virtio_id;
 	int minor;
 	struct eventfd_ctx *config_ctx;
@@ -158,7 +158,8 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
 	struct vdpa_device *vdpa = v->vdpa;
 	const struct vdpa_config_ops *ops = vdpa->config;
 	u8 status, status_old;
-	int ret, nvqs = v->nvqs;
+	u32 nvqs = v->nvqs;
+	int ret;
 	u16 i;
 
 	if (copy_from_user(&status, statusp, sizeof(status)))
@@ -965,7 +966,8 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
 	struct vhost_vdpa *v;
 	struct vhost_dev *dev;
 	struct vhost_virtqueue **vqs;
-	int nvqs, i, r, opened;
+	int r, opened;
+	u32 i, nvqs;
 
 	v = container_of(inode->i_cdev, struct vhost_vdpa, cdev);
 
@@ -1018,7 +1020,7 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
 
 static void vhost_vdpa_clean_irq(struct vhost_vdpa *v)
 {
-	int i;
+	u32 i;
 
 	for (i = 0; i < v->nvqs; i++)
 		vhost_vdpa_unsetup_vq_irq(v, i);
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index a526919..8943a20 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -83,7 +83,7 @@ struct vdpa_device {
 	unsigned int index;
 	bool features_valid;
 	bool use_va;
-	int nvqs;
+	u32 nvqs;
 	struct vdpa_mgmt_dev *mdev;
 };
 
@@ -338,10 +338,10 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
 				       dev_struct, member)), name, use_va), \
 				       dev_struct, member)
 
-int vdpa_register_device(struct vdpa_device *vdev, int nvqs);
+int vdpa_register_device(struct vdpa_device *vdev, u32 nvqs);
 void vdpa_unregister_device(struct vdpa_device *vdev);
 
-int _vdpa_register_device(struct vdpa_device *vdev, int nvqs);
+int _vdpa_register_device(struct vdpa_device *vdev, u32 nvqs);
 void _vdpa_unregister_device(struct vdpa_device *vdev);
 
 /**
-- 
1.8.3.1

[PATCH v2 3/3] vdpa: support exposing the count of vqs to userspace

[Longpeng(Mike)]

From: Longpeng <longpeng2@huawei.com>

- GET_VQS_COUNT: the count of virtqueues that exposed

Signed-off-by: Longpeng <longpeng2@huawei.com>
---
 drivers/vhost/vdpa.c       | 13 +++++++++++++
 include/uapi/linux/vhost.h |  3 +++
 2 files changed, 16 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 0c82eb5..69b3f05 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -370,6 +370,16 @@ static long vhost_vdpa_get_config_size(struct vhost_vdpa *v, u32 __user *argp)
 	return 0;
 }
 
+static long vhost_vdpa_get_vqs_count(struct vhost_vdpa *v, u32 __user *argp)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+
+	if (copy_to_user(argp, &vdpa->nvqs, sizeof(vdpa->nvqs)))
+		return -EFAULT;
+
+	return 0;
+}
+
 static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 				   void __user *argp)
 {
@@ -510,6 +520,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
 	case VHOST_VDPA_GET_CONFIG_SIZE:
 		r = vhost_vdpa_get_config_size(v, argp);
 		break;
+	case VHOST_VDPA_GET_VQS_COUNT:
+		r = vhost_vdpa_get_vqs_count(v, argp);
+		break;
 	default:
 		r = vhost_dev_ioctl(&v->vdev, cmd, argp);
 		if (r == -ENOIOCTLCMD)
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index bc74e95..5d99e7c 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -154,4 +154,7 @@
 /* Get the config size */
 #define VHOST_VDPA_GET_CONFIG_SIZE	_IOR(VHOST_VIRTIO, 0x79, __u32)
 
+/* Get the count of all virtqueues */
+#define VHOST_VDPA_GET_VQS_COUNT	_IOR(VHOST_VIRTIO, 0x80, __u32)
+
 #endif
-- 
1.8.3.1

Re: [PATCH v2 1/3] vdpa: support exposing the config size to userspace

[Stefano Garzarella]

On Tue, Mar 15, 2022 at 11:25:51AM +0800, Longpeng(Mike) wrote:
>From: Longpeng <longpeng2@huawei.com>
>
>- GET_CONFIG_SIZE: return the size of the virtio config space.
>
>The size contains the fields which are conditional on feature
>bits.
>
>Acked-by: Jason Wang <jasowang@redhat.com>
>Signed-off-by: Longpeng <longpeng2@huawei.com>
>---
> drivers/vhost/vdpa.c       | 17 +++++++++++++++++
> include/linux/vdpa.h       |  3 ++-
> include/uapi/linux/vhost.h |  4 ++++
> 3 files changed, 23 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>index ec5249e..605c7ae 100644
>--- a/drivers/vhost/vdpa.c
>+++ b/drivers/vhost/vdpa.c
>@@ -355,6 +355,20 @@ static long vhost_vdpa_get_iova_range(struct vhost_vdpa *v, u32 __user *argp)
> 	return 0;
> }
>
>+static long vhost_vdpa_get_config_size(struct vhost_vdpa *v, u32 __user *argp)
>+{
>+	struct vdpa_device *vdpa = v->vdpa;
>+	const struct vdpa_config_ops *ops = vdpa->config;
>+	u32 size;
>+
>+	size = ops->get_config_size(vdpa);

get_config_size() returns a size_t, perhaps we could have a comment here 
where we say we don't expect there to be an overflow.

I don't have a strong opinion on this, and I wouldn't want to get you to 
repin just for that, so:

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

Re: [PATCH v2 2/3] vdpa: change the type of nvqs to u32

[Stefano Garzarella]

On Tue, Mar 15, 2022 at 11:25:52AM +0800, Longpeng(Mike) wrote:
>From: Longpeng <longpeng2@huawei.com>
>
>Change vdpa_device.nvqs and vhost_vdpa.nvqs to use u32
>
>Signed-off-by: Longpeng <longpeng2@huawei.com>
>---
> drivers/vdpa/vdpa.c  |  6 +++---
> drivers/vhost/vdpa.c | 10 ++++++----
> include/linux/vdpa.h |  6 +++---
> 3 files changed, 12 insertions(+), 10 deletions(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

Re: [PATCH v2 3/3] vdpa: support exposing the count of vqs to userspace

[Stefano Garzarella]

On Tue, Mar 15, 2022 at 11:25:53AM +0800, Longpeng(Mike) wrote:
>From: Longpeng <longpeng2@huawei.com>
>
>- GET_VQS_COUNT: the count of virtqueues that exposed
>
>Signed-off-by: Longpeng <longpeng2@huawei.com>
>---
> drivers/vhost/vdpa.c       | 13 +++++++++++++
> include/uapi/linux/vhost.h |  3 +++
> 2 files changed, 16 insertions(+)
>
>diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>index 0c82eb5..69b3f05 100644
>--- a/drivers/vhost/vdpa.c
>+++ b/drivers/vhost/vdpa.c
>@@ -370,6 +370,16 @@ static long vhost_vdpa_get_config_size(struct vhost_vdpa *v, u32 __user *argp)
> 	return 0;
> }
>
>+static long vhost_vdpa_get_vqs_count(struct vhost_vdpa *v, u32 __user *argp)
>+{
>+	struct vdpa_device *vdpa = v->vdpa;
>+
>+	if (copy_to_user(argp, &vdpa->nvqs, sizeof(vdpa->nvqs)))
>+		return -EFAULT;
>+
>+	return 0;
>+}
>+
> static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
> 				   void __user *argp)
> {
>@@ -510,6 +520,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
> 	case VHOST_VDPA_GET_CONFIG_SIZE:
> 		r = vhost_vdpa_get_config_size(v, argp);
> 		break;
>+	case VHOST_VDPA_GET_VQS_COUNT:
>+		r = vhost_vdpa_get_vqs_count(v, argp);
>+		break;
> 	default:
> 		r = vhost_dev_ioctl(&v->vdev, cmd, argp);
> 		if (r == -ENOIOCTLCMD)
>diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
>index bc74e95..5d99e7c 100644
>--- a/include/uapi/linux/vhost.h
>+++ b/include/uapi/linux/vhost.h
>@@ -154,4 +154,7 @@
> /* Get the config size */
> #define VHOST_VDPA_GET_CONFIG_SIZE	_IOR(VHOST_VIRTIO, 0x79, __u32)
>
>+/* Get the count of all virtqueues */
>+#define VHOST_VDPA_GET_VQS_COUNT	_IOR(VHOST_VIRTIO, 0x80, __u32)

I'd prefer VHOST_VDPA_GET_NUM_QUEUES, since we use "num_queues" also in 
the spec [1].

But I'm fine also with this:

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

[1] 
https://docs.oasis-open.org/virtio/virtio/v1.1/csprd01/virtio-v1.1-csprd01.html#x1-1120003