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

[RFC 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)

Patch 3 supports ctrl vq for vdpasim_net, then guys can test the
generic vDPA device on the vdpasim_net/blk.

[1] https://lore.kernel.org/all/20220105005900.860-1-longpeng2@huawei.com/

Longpeng (3):
  vdpa: support exposing the config size to userspace
  vdpa: support exposing the count of vqs to userspace
  vdpasim_net: control virtqueue support

 drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 83 +++++++++++++++++++++++++++-
 drivers/vhost/vdpa.c                 | 30 ++++++++++
 include/uapi/linux/vhost.h           |  7 +++
 3 files changed, 118 insertions(+), 2 deletions(-)

-- 
2.23.0

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

[Longpeng(Mike)]

From: Longpeng <longpeng2@huawei.com>

- GET_CONFIG_SIZE: the size of the virtio config space

Signed-off-by: Longpeng <longpeng2@huawei.com>
---
 drivers/vhost/vdpa.c       | 17 +++++++++++++++++
 include/uapi/linux/vhost.h |  4 ++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 29cced1cd277..1eea14a4ea56 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/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index c998860d7bbc..bc74e95a273a 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
-- 
2.23.0

[RFC 2/3] 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 1eea14a4ea56..c1074278fc6b 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -369,6 +369,16 @@ 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)
 {
@@ -509,6 +519,9 @@ 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 bc74e95a273a..5d99e7c242a2 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
-- 
2.23.0

[RFC 3/3] vdpasim_net: control virtqueue support

[Longpeng(Mike)]

From: Longpeng <longpeng2@huawei.com>

Introduces the control virtqueue support for vdpasim_net, based on
Jason's RFC [1].

[1] https://patchwork.kernel.org/project/kvm/patch/20200924032125.18619-25-jasowang@redhat.com/

Signed-off-by: Longpeng <longpeng2@huawei.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 83 +++++++++++++++++++++++++++-
 1 file changed, 81 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
index 76dd24abc791..e9e388fd3cff 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
@@ -26,9 +26,85 @@
 #define DRV_LICENSE  "GPL v2"
 
 #define VDPASIM_NET_FEATURES	(VDPASIM_FEATURES | \
-				 (1ULL << VIRTIO_NET_F_MAC))
+				 (1ULL << VIRTIO_NET_F_MAC) | \
+				 (1ULL << VIRTIO_NET_F_CTRL_VQ) | \
+				 (1ULL << VIRTIO_NET_F_CTRL_MAC_ADDR))
 
-#define VDPASIM_NET_VQ_NUM	2
+#define VDPASIM_NET_VQ_NUM	3
+
+virtio_net_ctrl_ack vdpasim_net_handle_ctrl_mac(struct vdpasim *vdpasim,
+						u8 cmd)
+{
+	struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
+	virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
+	struct virtio_net_config *config = vdpasim->config;
+	size_t read;
+
+	switch (cmd) {
+	case VIRTIO_NET_CTRL_MAC_ADDR_SET:
+		read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->out_iov,
+					     (void *)config->mac, ETH_ALEN);
+		if (read == ETH_ALEN)
+			status = VIRTIO_NET_OK;
+		break;
+	default:
+		break;
+	}
+
+	return status;
+}
+
+static void vdpasim_net_handle_cvq(struct vdpasim *vdpasim)
+{
+	struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
+	virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
+	struct virtio_net_ctrl_hdr ctrl;
+	size_t read, write;
+	int err;
+
+	if (!(vdpasim->features & (1ULL << VIRTIO_NET_F_CTRL_VQ)))
+		return;
+
+	if (!cvq->ready)
+		return;
+
+	while (true) {
+		err = vringh_getdesc_iotlb(&cvq->vring, &cvq->out_iov, &cvq->in_iov,
+					   &cvq->head, GFP_ATOMIC);
+		if (err <= 0)
+			break;
+
+		read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->in_iov, &ctrl,
+					     sizeof(ctrl));
+		if (read != sizeof(ctrl))
+			break;
+
+		switch (ctrl.class) {
+		case VIRTIO_NET_CTRL_MAC:
+			status = vdpasim_net_handle_ctrl_mac(vdpasim, ctrl.cmd);
+			break;
+		default:
+			break;
+		}
+
+		/* Make sure data is wrote before advancing index */
+		smp_wmb();
+
+		write = vringh_iov_push_iotlb(&cvq->vring, &cvq->out_iov,
+					      &status, sizeof (status));
+		vringh_complete_iotlb(&cvq->vring, cvq->head, write);
+		vringh_kiov_cleanup(&cvq->in_iov);
+		vringh_kiov_cleanup(&cvq->out_iov);
+
+		/* Make sure used is visible before rasing the interrupt. */
+		smp_wmb();
+
+		local_bh_disable();
+		if (vringh_need_notify_iotlb(&cvq->vring) > 0)
+			vringh_notify(&cvq->vring);
+		local_bh_enable();
+	}
+}
 
 static void vdpasim_net_work(struct work_struct *work)
 {
@@ -42,6 +118,9 @@ static void vdpasim_net_work(struct work_struct *work)
 
 	spin_lock(&vdpasim->lock);
 
+	/* process ctrl vq first */
+	vdpasim_net_handle_cvq(vdpasim);
+
 	if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
 		goto out;
 
-- 
2.23.0

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

[Jason Wang]

在 2022/1/17 下午5:29, Longpeng(Mike) 写道:
> From: Longpeng <longpeng2@huawei.com>
>
> - GET_CONFIG_SIZE: the size of the virtio config space


I think we need to be verbose here. And it would be better to quote what 
spec said:

"

The device MUST allow reading of any device-specific configuration field 
before FEATURES_OK is set by the driver. This includes fields which are 
conditional on feature bits, as long as those feature bits are offered 
by the device.

"

I guess the size should contain the conditional on features bits.

(Or maybe we need to tweak the comment for get_config_size as well).

Other looks good.

Thanks


>
> Signed-off-by: Longpeng <longpeng2@huawei.com>
> ---
>   drivers/vhost/vdpa.c       | 17 +++++++++++++++++
>   include/uapi/linux/vhost.h |  4 ++++
>   2 files changed, 21 insertions(+)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 29cced1cd277..1eea14a4ea56 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/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
> index c998860d7bbc..bc74e95a273a 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

Re: [RFC 2/3] vdpa: support exposing the count of vqs to userspace

[Jason Wang]

在 2022/1/17 下午5:29, Longpeng(Mike) 写道:
> 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 1eea14a4ea56..c1074278fc6b 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -369,6 +369,16 @@ 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;


While at it, I think it's better to change vdpa->nvqs to use u32?

Thanks


> +
> +	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)
>   {
> @@ -509,6 +519,9 @@ 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 bc74e95a273a..5d99e7c242a2 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

Re: [RFC 3/3] vdpasim_net: control virtqueue support

[Jason Wang]

在 2022/1/17 下午5:29, Longpeng(Mike) 写道:
> From: Longpeng <longpeng2@huawei.com>
>
> Introduces the control virtqueue support for vdpasim_net, based on
> Jason's RFC [1].
>
> [1] https://patchwork.kernel.org/project/kvm/patch/20200924032125.18619-25-jasowang@redhat.com/


I'd expect to implement the receive filter as well[1]. This gives us a 
chance to test this.

Thanks

[1] https://lkml.org/lkml/2020/9/23/1269


>
> Signed-off-by: Longpeng <longpeng2@huawei.com>
> ---
>   drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 83 +++++++++++++++++++++++++++-
>   1 file changed, 81 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> index 76dd24abc791..e9e388fd3cff 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> @@ -26,9 +26,85 @@
>   #define DRV_LICENSE  "GPL v2"
>   
>   #define VDPASIM_NET_FEATURES	(VDPASIM_FEATURES | \
> -				 (1ULL << VIRTIO_NET_F_MAC))
> +				 (1ULL << VIRTIO_NET_F_MAC) | \
> +				 (1ULL << VIRTIO_NET_F_CTRL_VQ) | \
> +				 (1ULL << VIRTIO_NET_F_CTRL_MAC_ADDR))
>   
> -#define VDPASIM_NET_VQ_NUM	2
> +#define VDPASIM_NET_VQ_NUM	3
> +
> +virtio_net_ctrl_ack vdpasim_net_handle_ctrl_mac(struct vdpasim *vdpasim,
> +						u8 cmd)
> +{
> +	struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
> +	virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
> +	struct virtio_net_config *config = vdpasim->config;
> +	size_t read;
> +
> +	switch (cmd) {
> +	case VIRTIO_NET_CTRL_MAC_ADDR_SET:
> +		read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->out_iov,
> +					     (void *)config->mac, ETH_ALEN);
> +		if (read == ETH_ALEN)
> +			status = VIRTIO_NET_OK;
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return status;
> +}
> +
> +static void vdpasim_net_handle_cvq(struct vdpasim *vdpasim)
> +{
> +	struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
> +	virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
> +	struct virtio_net_ctrl_hdr ctrl;
> +	size_t read, write;
> +	int err;
> +
> +	if (!(vdpasim->features & (1ULL << VIRTIO_NET_F_CTRL_VQ)))
> +		return;
> +
> +	if (!cvq->ready)
> +		return;
> +
> +	while (true) {
> +		err = vringh_getdesc_iotlb(&cvq->vring, &cvq->out_iov, &cvq->in_iov,
> +					   &cvq->head, GFP_ATOMIC);
> +		if (err <= 0)
> +			break;
> +
> +		read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->in_iov, &ctrl,
> +					     sizeof(ctrl));
> +		if (read != sizeof(ctrl))
> +			break;
> +
> +		switch (ctrl.class) {
> +		case VIRTIO_NET_CTRL_MAC:
> +			status = vdpasim_net_handle_ctrl_mac(vdpasim, ctrl.cmd);
> +			break;
> +		default:
> +			break;
> +		}
> +
> +		/* Make sure data is wrote before advancing index */
> +		smp_wmb();
> +
> +		write = vringh_iov_push_iotlb(&cvq->vring, &cvq->out_iov,
> +					      &status, sizeof (status));
> +		vringh_complete_iotlb(&cvq->vring, cvq->head, write);
> +		vringh_kiov_cleanup(&cvq->in_iov);
> +		vringh_kiov_cleanup(&cvq->out_iov);
> +
> +		/* Make sure used is visible before rasing the interrupt. */
> +		smp_wmb();
> +
> +		local_bh_disable();
> +		if (vringh_need_notify_iotlb(&cvq->vring) > 0)
> +			vringh_notify(&cvq->vring);
> +		local_bh_enable();
> +	}
> +}
>   
>   static void vdpasim_net_work(struct work_struct *work)
>   {
> @@ -42,6 +118,9 @@ static void vdpasim_net_work(struct work_struct *work)
>   
>   	spin_lock(&vdpasim->lock);
>   
> +	/* process ctrl vq first */
> +	vdpasim_net_handle_cvq(vdpasim);
> +
>   	if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
>   		goto out;
>   

RE: [RFC 2/3] vdpa: support exposing the count of vqs to userspace

[Longpeng (Mike, Cloud Infrastructure Service Product Dept.)]

Hi Jason,

> -----Original Message-----
> From: Jason Wang [mailto:jasowang@redhat.com]
> Sent: Tuesday, January 18, 2022 11:08 AM
> To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> <longpeng2@huawei.com>; mst@redhat.com; sgarzare@redhat.com;
> stefanha@redhat.com
> Cc: virtualization@lists.linux-foundation.org; kvm@vger.kernel.org;
> linux-kernel@vger.kernel.org; netdev@vger.kernel.org; Gonglei (Arei)
> <arei.gonglei@huawei.com>; Yechuan <yechuan@huawei.com>; Huangzhichao
> <huangzhichao@huawei.com>
> Subject: Re: [RFC 2/3] vdpa: support exposing the count of vqs to userspace
> 
> 
> 在 2022/1/17 下午5:29, Longpeng(Mike) 写道:
> > 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 1eea14a4ea56..c1074278fc6b 100644
> > --- a/drivers/vhost/vdpa.c
> > +++ b/drivers/vhost/vdpa.c
> > @@ -369,6 +369,16 @@ 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;
> 
> 
> While at it, I think it's better to change vdpa->nvqs to use u32?
> 

struct vhost_vdpa {
    ...
	int nvqs;
    ...
};

struct vdpa_device {
    ...
	int nvqs;
    ...
};

I think we should change both to u32?


> Thanks
> 
> 
> > +
> > +	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)
> >   {
> > @@ -509,6 +519,9 @@ 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 bc74e95a273a..5d99e7c242a2 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