[PATCH 1/2] vdpa: support per virtqueue max queue size

[PATCH 1/2] vdpa: support per virtqueue max queue size

[Jason Wang]

Virtio spec allows the device to specify the per virtqueue max queue
size. vDPA needs to adapt to this flexibility. E.g Qemu advertise a
small control virtqueue for virtio-net.

So this patch adds a index parameter to get_vq_num_max bus operations
for the device to report its per virtqueue max queue size.

Both VHOST_VDPA_GET_VRING_NUM and VDPA_ATTR_DEV_MAX_VQ_SIZE assume a
global maximum size. So we iterate all the virtqueues to return the
minimal size in this case. Actually, the VHOST_VDPA_GET_VRING_NUM is
not a must for the userspace. Userspace may choose to check the
VHOST_SET_VRING_NUM for proving or validating the maximum virtqueue
size. Anyway, we can invent a per vq version of
VHOST_VDPA_GET_VRING_NUM in the future if it's necessary.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vdpa/ifcvf/ifcvf_main.c   |  2 +-
 drivers/vdpa/mlx5/net/mlx5_vnet.c |  2 +-
 drivers/vdpa/vdpa.c               | 22 +++++++++++++++++++++-
 drivers/vdpa/vdpa_sim/vdpa_sim.c  |  2 +-
 drivers/vdpa/virtio_pci/vp_vdpa.c |  2 +-
 drivers/vhost/vdpa.c              |  9 ++++++---
 drivers/virtio/virtio_vdpa.c      |  2 +-
 include/linux/vdpa.h              |  5 ++++-
 8 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index ab0ab5cf0f6e..646b340db2af 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -254,7 +254,7 @@ static void ifcvf_vdpa_set_status(struct vdpa_device *vdpa_dev, u8 status)
 	ifcvf_set_status(vf, status);
 }
 
-static u16 ifcvf_vdpa_get_vq_num_max(struct vdpa_device *vdpa_dev)
+static u16 ifcvf_vdpa_get_vq_num_max(struct vdpa_device *vdpa_dev, u16 qid)
 {
 	return IFCVF_QUEUE_MAX;
 }
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index dda5dc6f7737..afd6114d07b0 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1584,7 +1584,7 @@ static void mlx5_vdpa_set_config_cb(struct vdpa_device *vdev, struct vdpa_callba
 }
 
 #define MLX5_VDPA_MAX_VQ_ENTRIES 256
-static u16 mlx5_vdpa_get_vq_num_max(struct vdpa_device *vdev)
+static u16 mlx5_vdpa_get_vq_num_max(struct vdpa_device *vdev, u16 idx)
 {
 	return MLX5_VDPA_MAX_VQ_ENTRIES;
 }
diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index bb3f1d1f0422..d77d59811389 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -239,6 +239,26 @@ void vdpa_unregister_driver(struct vdpa_driver *drv)
 }
 EXPORT_SYMBOL_GPL(vdpa_unregister_driver);
 
+/**
+ * vdpa_get_vq_num_max - get the maximum virtqueue size
+ * @vdev: vdpa device
+ */
+u16 vdpa_get_vq_num_max(struct vdpa_device *vdev)
+{
+	const struct vdpa_config_ops *ops = vdev->config;
+	u16 s, size = ops->get_vq_num_max(vdev, 0);
+	int i;
+
+	for (i = 1; i < vdev->nvqs; i++) {
+		s = ops->get_vq_num_max(vdev, i);
+		if (s && s < size)
+			size = s;
+	}
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(vdpa_get_vq_num_max);
+
 /**
  * vdpa_mgmtdev_register - register a vdpa management device
  *
@@ -502,7 +522,7 @@ vdpa_dev_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq
 
 	device_id = vdev->config->get_device_id(vdev);
 	vendor_id = vdev->config->get_vendor_id(vdev);
-	max_vq_size = vdev->config->get_vq_num_max(vdev);
+	max_vq_size = vdpa_get_vq_num_max(vdev);
 
 	err = -EMSGSIZE;
 	if (nla_put_string(msg, VDPA_ATTR_DEV_NAME, dev_name(&vdev->dev)))
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 98f793bc9376..49e29056f164 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -422,7 +422,7 @@ static void vdpasim_set_config_cb(struct vdpa_device *vdpa,
 	/* We don't support config interrupt */
 }
 
-static u16 vdpasim_get_vq_num_max(struct vdpa_device *vdpa)
+static u16 vdpasim_get_vq_num_max(struct vdpa_device *vdpa, u16 idx)
 {
 	return VDPASIM_QUEUE_MAX;
 }
diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index c76ebb531212..2926641fb586 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -195,7 +195,7 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
 		vp_vdpa_free_irq(vp_vdpa);
 }
 
-static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
+static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
 {
 	return VP_VDPA_QUEUE_MAX;
 }
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index fb41db3da611..c9ec395b8c42 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -289,11 +289,14 @@ static long vhost_vdpa_set_features(struct vhost_vdpa *v, u64 __user *featurep)
 
 static long vhost_vdpa_get_vring_num(struct vhost_vdpa *v, u16 __user *argp)
 {
-	struct vdpa_device *vdpa = v->vdpa;
-	const struct vdpa_config_ops *ops = vdpa->config;
 	u16 num;
 
-	num = ops->get_vq_num_max(vdpa);
+	/*
+	 * VHOST_VDPA_GET_VRING_NUM asssumes a global max virtqueue
+	 * size. So we need to iterate all the virtqueue and return
+	 * the minimal one here.
+	 */
+	num = vdpa_get_vq_num_max(v->vdpa);
 
 	if (copy_to_user(argp, &num, sizeof(num)))
 		return -EFAULT;
diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
index e28acf482e0c..a43bd5ec5ac6 100644
--- a/drivers/virtio/virtio_vdpa.c
+++ b/drivers/virtio/virtio_vdpa.c
@@ -158,7 +158,7 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
 	if (!info)
 		return ERR_PTR(-ENOMEM);
 
-	num = ops->get_vq_num_max(vdpa);
+	num = ops->get_vq_num_max(vdpa, index);
 	if (num == 0) {
 		err = -ENOENT;
 		goto error_new_virtqueue;
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index f311d227aa1b..0f8977a54783 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -137,6 +137,7 @@ struct vdpa_iova_range {
  *				@cb: virtio-vdev interrupt callback structure
  * @get_vq_num_max:		Get the max size of virtqueue
  *				@vdev: vdpa device
+ *				@idx: virtqueue index
  *				Returns u16: max size of virtqueue
  * @get_device_id:		Get virtio device id
  *				@vdev: vdpa device
@@ -229,7 +230,7 @@ struct vdpa_config_ops {
 	int (*set_features)(struct vdpa_device *vdev, u64 features);
 	void (*set_config_cb)(struct vdpa_device *vdev,
 			      struct vdpa_callback *cb);
-	u16 (*get_vq_num_max)(struct vdpa_device *vdev);
+	u16 (*get_vq_num_max)(struct vdpa_device *vdev, u16 idx);
 	u32 (*get_device_id)(struct vdpa_device *vdev);
 	u32 (*get_vendor_id)(struct vdpa_device *vdev);
 	u8 (*get_status)(struct vdpa_device *vdev);
@@ -270,6 +271,8 @@ void vdpa_unregister_device(struct vdpa_device *vdev);
 int _vdpa_register_device(struct vdpa_device *vdev, int nvqs);
 void _vdpa_unregister_device(struct vdpa_device *vdev);
 
+u16 vdpa_get_vq_num_max(struct vdpa_device *vdev);
+
 /**
  * struct vdpa_driver - operations for a vDPA driver
  * @driver: underlying device driver
-- 
2.25.1

[PATCH 2/2] vdpa: vp_vdpa: don't use hard-coded maximum virtqueue size

[Jason Wang]

This patch switch to read virtqueue size from the capability instead
of depending on the hardcoded value. This allows the per virtqueue
size could be advertised.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vdpa/virtio_pci/vp_vdpa.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index 2926641fb586..198f7076e4d9 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -18,7 +18,6 @@
 #include <linux/virtio_pci.h>
 #include <linux/virtio_pci_modern.h>
 
-#define VP_VDPA_QUEUE_MAX 256
 #define VP_VDPA_DRIVER_NAME "vp_vdpa"
 #define VP_VDPA_NAME_SIZE 256
 
@@ -197,7 +196,10 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
 
 static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
 {
-	return VP_VDPA_QUEUE_MAX;
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+	struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
+
+	return vp_modern_get_queue_size(mdev, qid);
 }
 
 static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
-- 
2.25.1

Re: [PATCH 2/2] vdpa: vp_vdpa: don't use hard-coded maximum virtqueue size

[Michael S. Tsirkin]

On Mon, Jul 05, 2021 at 03:19:10PM +0800, Jason Wang wrote:
> This patch switch to read virtqueue size from the capability instead
> of depending on the hardcoded value. This allows the per virtqueue
> size could be advertised.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>

So let's add an ioctl for this? It's really a bug we don't..

> ---
>  drivers/vdpa/virtio_pci/vp_vdpa.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index 2926641fb586..198f7076e4d9 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -18,7 +18,6 @@
>  #include <linux/virtio_pci.h>
>  #include <linux/virtio_pci_modern.h>
>  
> -#define VP_VDPA_QUEUE_MAX 256
>  #define VP_VDPA_DRIVER_NAME "vp_vdpa"
>  #define VP_VDPA_NAME_SIZE 256
>  
> @@ -197,7 +196,10 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
>  
>  static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
>  {
> -	return VP_VDPA_QUEUE_MAX;
> +	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
> +	struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
> +
> +	return vp_modern_get_queue_size(mdev, qid);
>  }
>  
>  static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
> -- 
> 2.25.1

Re: [PATCH 2/2] vdpa: vp_vdpa: don't use hard-coded maximum virtqueue size

[Jason Wang]

在 2021/7/5 下午3:26, Michael S. Tsirkin 写道:
> On Mon, Jul 05, 2021 at 03:19:10PM +0800, Jason Wang wrote:
>> This patch switch to read virtqueue size from the capability instead
>> of depending on the hardcoded value. This allows the per virtqueue
>> size could be advertised.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
> So let's add an ioctl for this? It's really a bug we don't..


As explained in patch 1. Qemu doesn't use VHOST_VDPA_GET_VRING_NUM 
actually. Instead it checks the result VHOST_VDPA_SET_VRING_NUM.

So I change VHOST_VDPA_GET_VRING_NUM to return the minimal size of all 
the virtqueues.

If you wish we can add a VHOST_VDPA_GET_VRING_NUM2, but I'm not sure it 
will have a user or not.

Thanks


>
>> ---
>>   drivers/vdpa/virtio_pci/vp_vdpa.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
>> index 2926641fb586..198f7076e4d9 100644
>> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
>> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
>> @@ -18,7 +18,6 @@
>>   #include <linux/virtio_pci.h>
>>   #include <linux/virtio_pci_modern.h>
>>   
>> -#define VP_VDPA_QUEUE_MAX 256
>>   #define VP_VDPA_DRIVER_NAME "vp_vdpa"
>>   #define VP_VDPA_NAME_SIZE 256
>>   
>> @@ -197,7 +196,10 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
>>   
>>   static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
>>   {
>> -	return VP_VDPA_QUEUE_MAX;
>> +	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
>> +	struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
>> +
>> +	return vp_modern_get_queue_size(mdev, qid);
>>   }
>>   
>>   static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
>> -- 
>> 2.25.1

Re: [PATCH 2/2] vdpa: vp_vdpa: don't use hard-coded maximum virtqueue size

[Michael S. Tsirkin]

On Mon, Jul 05, 2021 at 03:29:47PM +0800, Jason Wang wrote:
> 
> 在 2021/7/5 下午3:26, Michael S. Tsirkin 写道:
> > On Mon, Jul 05, 2021 at 03:19:10PM +0800, Jason Wang wrote:
> > > This patch switch to read virtqueue size from the capability instead
> > > of depending on the hardcoded value. This allows the per virtqueue
> > > size could be advertised.
> > > 
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > So let's add an ioctl for this? It's really a bug we don't..
> 
> 
> As explained in patch 1. Qemu doesn't use VHOST_VDPA_GET_VRING_NUM actually.
> Instead it checks the result VHOST_VDPA_SET_VRING_NUM.
> 
> So I change VHOST_VDPA_GET_VRING_NUM to return the minimal size of all the
> virtqueues.
> 
> If you wish we can add a VHOST_VDPA_GET_VRING_NUM2, but I'm not sure it will
> have a user or not.
> 
> Thanks

Question is how do we know returning the minimal and not e.g. the max
size is the right thing to do?


> 
> > 
> > > ---
> > >   drivers/vdpa/virtio_pci/vp_vdpa.c | 6 ++++--
> > >   1 file changed, 4 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> > > index 2926641fb586..198f7076e4d9 100644
> > > --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> > > +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> > > @@ -18,7 +18,6 @@
> > >   #include <linux/virtio_pci.h>
> > >   #include <linux/virtio_pci_modern.h>
> > > -#define VP_VDPA_QUEUE_MAX 256
> > >   #define VP_VDPA_DRIVER_NAME "vp_vdpa"
> > >   #define VP_VDPA_NAME_SIZE 256
> > > @@ -197,7 +196,10 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
> > >   static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
> > >   {
> > > -	return VP_VDPA_QUEUE_MAX;
> > > +	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
> > > +	struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
> > > +
> > > +	return vp_modern_get_queue_size(mdev, qid);
> > >   }
> > >   static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
> > > -- 
> > > 2.25.1

Re: [PATCH 2/2] vdpa: vp_vdpa: don't use hard-coded maximum virtqueue size

[Jason Wang]

在 2021/7/6 上午1:59, Michael S. Tsirkin 写道:
> On Mon, Jul 05, 2021 at 03:29:47PM +0800, Jason Wang wrote:
>> 在 2021/7/5 下午3:26, Michael S. Tsirkin 写道:
>>> On Mon, Jul 05, 2021 at 03:19:10PM +0800, Jason Wang wrote:
>>>> This patch switch to read virtqueue size from the capability instead
>>>> of depending on the hardcoded value. This allows the per virtqueue
>>>> size could be advertised.
>>>>
>>>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>>> So let's add an ioctl for this? It's really a bug we don't..
>>
>> As explained in patch 1. Qemu doesn't use VHOST_VDPA_GET_VRING_NUM actually.
>> Instead it checks the result VHOST_VDPA_SET_VRING_NUM.
>>
>> So I change VHOST_VDPA_GET_VRING_NUM to return the minimal size of all the
>> virtqueues.
>>
>> If you wish we can add a VHOST_VDPA_GET_VRING_NUM2, but I'm not sure it will
>> have a user or not.
>>
>> Thanks
> Question is how do we know returning the minimal and not e.g. the max
> size is the right thing to do?


For the new ioctl, it will return the max queue size per vq.

It's probably too late to fix the old one, so it's only safe to return 
the minimal one.

Actually, most of the vDPA parents should be fine except for the 
vp_vdpa. When running in a nested environment, Qemu only advertise cvq 
with 64 entries.

Thanks


>
>
>>>> ---
>>>>    drivers/vdpa/virtio_pci/vp_vdpa.c | 6 ++++--
>>>>    1 file changed, 4 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
>>>> index 2926641fb586..198f7076e4d9 100644
>>>> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
>>>> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
>>>> @@ -18,7 +18,6 @@
>>>>    #include <linux/virtio_pci.h>
>>>>    #include <linux/virtio_pci_modern.h>
>>>> -#define VP_VDPA_QUEUE_MAX 256
>>>>    #define VP_VDPA_DRIVER_NAME "vp_vdpa"
>>>>    #define VP_VDPA_NAME_SIZE 256
>>>> @@ -197,7 +196,10 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
>>>>    static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
>>>>    {
>>>> -	return VP_VDPA_QUEUE_MAX;
>>>> +	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
>>>> +	struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
>>>> +
>>>> +	return vp_modern_get_queue_size(mdev, qid);
>>>>    }
>>>>    static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
>>>> -- 
>>>> 2.25.1

Re: [PATCH 1/2] vdpa: support per virtqueue max queue size

[Stefan Hajnoczi]

[-- Attachment #1: Type: text/plain, Size: 1424 bytes --]

On Mon, Jul 05, 2021 at 03:19:09PM +0800, Jason Wang wrote:
> Virtio spec allows the device to specify the per virtqueue max queue
> size. vDPA needs to adapt to this flexibility. E.g Qemu advertise a
> small control virtqueue for virtio-net.
> 
> So this patch adds a index parameter to get_vq_num_max bus operations
> for the device to report its per virtqueue max queue size.
> 
> Both VHOST_VDPA_GET_VRING_NUM and VDPA_ATTR_DEV_MAX_VQ_SIZE assume a
> global maximum size. So we iterate all the virtqueues to return the
> minimal size in this case. Actually, the VHOST_VDPA_GET_VRING_NUM is
> not a must for the userspace. Userspace may choose to check the
> VHOST_SET_VRING_NUM for proving or validating the maximum virtqueue
> size. Anyway, we can invent a per vq version of
> VHOST_VDPA_GET_VRING_NUM in the future if it's necessary.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  drivers/vdpa/ifcvf/ifcvf_main.c   |  2 +-
>  drivers/vdpa/mlx5/net/mlx5_vnet.c |  2 +-
>  drivers/vdpa/vdpa.c               | 22 +++++++++++++++++++++-
>  drivers/vdpa/vdpa_sim/vdpa_sim.c  |  2 +-
>  drivers/vdpa/virtio_pci/vp_vdpa.c |  2 +-
>  drivers/vhost/vdpa.c              |  9 ++++++---
>  drivers/virtio/virtio_vdpa.c      |  2 +-
>  include/linux/vdpa.h              |  5 ++++-
>  8 files changed, 36 insertions(+), 10 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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Re: [PATCH 1/2] vdpa: support per virtqueue max queue size

[Yongji Xie]

On Mon, Jul 5, 2021 at 3:19 PM Jason Wang <jasowang@redhat.com> wrote:
>
> Virtio spec allows the device to specify the per virtqueue max queue
> size. vDPA needs to adapt to this flexibility. E.g Qemu advertise a
> small control virtqueue for virtio-net.
>
> So this patch adds a index parameter to get_vq_num_max bus operations
> for the device to report its per virtqueue max queue size.
>
> Both VHOST_VDPA_GET_VRING_NUM and VDPA_ATTR_DEV_MAX_VQ_SIZE assume a
> global maximum size. So we iterate all the virtqueues to return the
> minimal size in this case. Actually, the VHOST_VDPA_GET_VRING_NUM is
> not a must for the userspace. Userspace may choose to check the
> VHOST_SET_VRING_NUM for proving or validating the maximum virtqueue
> size. Anyway, we can invent a per vq version of
> VHOST_VDPA_GET_VRING_NUM in the future if it's necessary.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  drivers/vdpa/ifcvf/ifcvf_main.c   |  2 +-
>  drivers/vdpa/mlx5/net/mlx5_vnet.c |  2 +-
>  drivers/vdpa/vdpa.c               | 22 +++++++++++++++++++++-
>  drivers/vdpa/vdpa_sim/vdpa_sim.c  |  2 +-
>  drivers/vdpa/virtio_pci/vp_vdpa.c |  2 +-
>  drivers/vhost/vdpa.c              |  9 ++++++---
>  drivers/virtio/virtio_vdpa.c      |  2 +-
>  include/linux/vdpa.h              |  5 ++++-
>  8 files changed, 36 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> index ab0ab5cf0f6e..646b340db2af 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -254,7 +254,7 @@ static void ifcvf_vdpa_set_status(struct vdpa_device *vdpa_dev, u8 status)
>         ifcvf_set_status(vf, status);
>  }
>
> -static u16 ifcvf_vdpa_get_vq_num_max(struct vdpa_device *vdpa_dev)
> +static u16 ifcvf_vdpa_get_vq_num_max(struct vdpa_device *vdpa_dev, u16 qid)
>  {
>         return IFCVF_QUEUE_MAX;
>  }
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index dda5dc6f7737..afd6114d07b0 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1584,7 +1584,7 @@ static void mlx5_vdpa_set_config_cb(struct vdpa_device *vdev, struct vdpa_callba
>  }
>
>  #define MLX5_VDPA_MAX_VQ_ENTRIES 256
> -static u16 mlx5_vdpa_get_vq_num_max(struct vdpa_device *vdev)
> +static u16 mlx5_vdpa_get_vq_num_max(struct vdpa_device *vdev, u16 idx)
>  {
>         return MLX5_VDPA_MAX_VQ_ENTRIES;
>  }
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index bb3f1d1f0422..d77d59811389 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -239,6 +239,26 @@ void vdpa_unregister_driver(struct vdpa_driver *drv)
>  }
>  EXPORT_SYMBOL_GPL(vdpa_unregister_driver);
>
> +/**
> + * vdpa_get_vq_num_max - get the maximum virtqueue size
> + * @vdev: vdpa device
> + */
> +u16 vdpa_get_vq_num_max(struct vdpa_device *vdev)
> +{
> +       const struct vdpa_config_ops *ops = vdev->config;
> +       u16 s, size = ops->get_vq_num_max(vdev, 0);
> +       int i;
> +
> +       for (i = 1; i < vdev->nvqs; i++) {
> +               s = ops->get_vq_num_max(vdev, i);
> +               if (s && s < size)
> +                       size = s;
> +       }
> +
> +       return size;
> +}
> +EXPORT_SYMBOL_GPL(vdpa_get_vq_num_max);
> +
>  /**
>   * vdpa_mgmtdev_register - register a vdpa management device
>   *
> @@ -502,7 +522,7 @@ vdpa_dev_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq
>
>         device_id = vdev->config->get_device_id(vdev);
>         vendor_id = vdev->config->get_vendor_id(vdev);
> -       max_vq_size = vdev->config->get_vq_num_max(vdev);
> +       max_vq_size = vdpa_get_vq_num_max(vdev);
>
>         err = -EMSGSIZE;
>         if (nla_put_string(msg, VDPA_ATTR_DEV_NAME, dev_name(&vdev->dev)))
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index 98f793bc9376..49e29056f164 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -422,7 +422,7 @@ static void vdpasim_set_config_cb(struct vdpa_device *vdpa,
>         /* We don't support config interrupt */
>  }
>
> -static u16 vdpasim_get_vq_num_max(struct vdpa_device *vdpa)
> +static u16 vdpasim_get_vq_num_max(struct vdpa_device *vdpa, u16 idx)
>  {
>         return VDPASIM_QUEUE_MAX;
>  }
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index c76ebb531212..2926641fb586 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -195,7 +195,7 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
>                 vp_vdpa_free_irq(vp_vdpa);
>  }
>
> -static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
> +static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
>  {
>         return VP_VDPA_QUEUE_MAX;
>  }
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index fb41db3da611..c9ec395b8c42 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -289,11 +289,14 @@ static long vhost_vdpa_set_features(struct vhost_vdpa *v, u64 __user *featurep)
>
>  static long vhost_vdpa_get_vring_num(struct vhost_vdpa *v, u16 __user *argp)
>  {
> -       struct vdpa_device *vdpa = v->vdpa;
> -       const struct vdpa_config_ops *ops = vdpa->config;
>         u16 num;
>
> -       num = ops->get_vq_num_max(vdpa);
> +       /*
> +        * VHOST_VDPA_GET_VRING_NUM asssumes a global max virtqueue

s/asssumes/assumes. Other looks good to me.

Thanks,
Yongji

Re: [PATCH 1/2] vdpa: support per virtqueue max queue size

[Jason Wang]

在 2021/7/7 下午12:04, Yongji Xie 写道:
>>   static long vhost_vdpa_get_vring_num(struct vhost_vdpa *v, u16 __user *argp)
>>   {
>> -       struct vdpa_device *vdpa = v->vdpa;
>> -       const struct vdpa_config_ops *ops = vdpa->config;
>>          u16 num;
>>
>> -       num = ops->get_vq_num_max(vdpa);
>> +       /*
>> +        * VHOST_VDPA_GET_VRING_NUM asssumes a global max virtqueue
> s/asssumes/assumes. Other looks good to me.
>
> Thanks,
> Yongji
>

Will fix.

Thanks