Re: [PATCH v6 06/26] virtio_ring: packed: extrace the logic of creating vring

[Jason Wang <jasowang@xxxxxxxxxx>]

在 2022/3/8 下午3:01, Xuan Zhuo 写道:
> On Mon, 7 Mar 2022 17:17:51 -0500, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
> > On Thu, Feb 24, 2022 at 04:10:42PM +0800, Xuan Zhuo wrote:
> > > Separate the logic of packed to create vring queue.
> > >
> > > For the convenience of passing parameters, add a structure
> > > vring_packed.
> > >
> > > This feature is required for subsequent virtuqueue reset vring.
> > >
> > > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > Subject has a typo.
> I will fix it.
>
> > Besides:
> >
> > > ---
> > >   drivers/virtio/virtio_ring.c | 121 ++++++++++++++++++++++++++---------
> > >   1 file changed, 92 insertions(+), 29 deletions(-)
> > >
> > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > > index dc6313b79305..41864c5e665f 100644
> > > --- a/drivers/virtio/virtio_ring.c
> > > +++ b/drivers/virtio/virtio_ring.c
> > > @@ -92,6 +92,18 @@ struct vring_split {
> > >   	struct vring vring;
> > >   };
> > >
> > > +struct vring_packed {
> > > +	u32 num;
> > > +	struct vring_packed_desc *ring;
> > > +	struct vring_packed_desc_event *driver;
> > > +	struct vring_packed_desc_event *device;
> > > +	dma_addr_t ring_dma_addr;
> > > +	dma_addr_t driver_event_dma_addr;
> > > +	dma_addr_t device_event_dma_addr;
> > > +	size_t ring_size_in_bytes;
> > > +	size_t event_size_in_bytes;
> > > +};
> > > +
> > >   struct vring_virtqueue {
> > >   	struct virtqueue vq;
> > >
> > > @@ -1683,45 +1695,101 @@ static struct vring_desc_extra *vring_alloc_desc_extra(struct vring_virtqueue *v
> > >   	return desc_extra;
> > >   }
> > >
> > > -static struct virtqueue *vring_create_virtqueue_packed(
> > > -	unsigned int index,
> > > -	unsigned int num,
> > > -	unsigned int vring_align,
> > > -	struct virtio_device *vdev,
> > > -	bool weak_barriers,
> > > -	bool may_reduce_num,
> > > -	bool context,
> > > -	bool (*notify)(struct virtqueue *),
> > > -	void (*callback)(struct virtqueue *),
> > > -	const char *name)
> > > +static void vring_free_vring_packed(struct vring_packed *vring,
> > > +				    struct virtio_device *vdev)
> > > +{
> > > +	dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr;
> > > +	struct vring_packed_desc_event *driver, *device;
> > > +	size_t ring_size_in_bytes, event_size_in_bytes;
> > > +	struct vring_packed_desc *ring;
> > > +
> > > +	ring                  = vring->ring;
> > > +	driver                = vring->driver;
> > > +	device                = vring->device;
> > > +	ring_dma_addr         = vring->ring_size_in_bytes;
> > > +	event_size_in_bytes   = vring->event_size_in_bytes;
> > > +	ring_dma_addr         = vring->ring_dma_addr;
> > > +	driver_event_dma_addr = vring->driver_event_dma_addr;
> > > +	device_event_dma_addr = vring->device_event_dma_addr;
> > > +
> > > +	if (device)
> > > +		vring_free_queue(vdev, event_size_in_bytes, device, device_event_dma_addr);
> > > +
> > > +	if (driver)
> > > +		vring_free_queue(vdev, event_size_in_bytes, driver, driver_event_dma_addr);
> > > +
> > > +	if (ring)
> > > +		vring_free_queue(vdev, ring_size_in_bytes, ring, ring_dma_addr);
> > ring_size_in_bytes is uninitialized here.
> >
> > Which begs the question how was this tested patchset generally and
> > this patch in particular.
> > Please add note on tested configurations and tests run to the patchset.
> Sorry, my environment is running in split mode. I did not retest the packed mode
> before sending patches. Because my dpdk vhost-user is not easy to use, I
> need to change the kernel of the host.
>
> I would like to ask if there are other lightweight environments that can be used
> to test packed mode.


You can use Qemu's dataplane. It has support for packed virtqueue.

Thanks


> Thanks.
>
>
> > > +}
> > > +
> > > +static int vring_create_vring_packed(struct vring_packed *vring,
> > > +				    struct virtio_device *vdev,
> > > +				    u32 num)
> > >   {
> > > -	struct vring_virtqueue *vq;
> > >   	struct vring_packed_desc *ring;
> > >   	struct vring_packed_desc_event *driver, *device;
> > >   	dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr;
> > >   	size_t ring_size_in_bytes, event_size_in_bytes;
> > >
> > > +	memset(vring, 0, sizeof(*vring));
> > > +
> > >   	ring_size_in_bytes = num * sizeof(struct vring_packed_desc);
> > >
> > >   	ring = vring_alloc_queue(vdev, ring_size_in_bytes,
> > >   				 &ring_dma_addr,
> > >   				 GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
> > >   	if (!ring)
> > > -		goto err_ring;
> > > +		goto err;
> > > +
> > > +	vring->num = num;
> > > +	vring->ring = ring;
> > > +	vring->ring_size_in_bytes = ring_size_in_bytes;
> > > +	vring->ring_dma_addr = ring_dma_addr;
> > >
> > >   	event_size_in_bytes = sizeof(struct vring_packed_desc_event);
> > > +	vring->event_size_in_bytes = event_size_in_bytes;
> > >
> > >   	driver = vring_alloc_queue(vdev, event_size_in_bytes,
> > >   				   &driver_event_dma_addr,
> > >   				   GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
> > >   	if (!driver)
> > > -		goto err_driver;
> > > +		goto err;
> > > +
> > > +	vring->driver = driver;
> > > +	vring->driver_event_dma_addr = driver_event_dma_addr;
> > >
> > >   	device = vring_alloc_queue(vdev, event_size_in_bytes,
> > >   				   &device_event_dma_addr,
> > >   				   GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
> > >   	if (!device)
> > > -		goto err_device;
> > > +		goto err;
> > > +
> > > +	vring->device = device;
> > > +	vring->device_event_dma_addr = device_event_dma_addr;
> > > +	return 0;
> > > +
> > > +err:
> > > +	vring_free_vring_packed(vring, vdev);
> > > +	return -ENOMEM;
> > > +}
> > > +
> > > +static struct virtqueue *vring_create_virtqueue_packed(
> > > +	unsigned int index,
> > > +	unsigned int num,
> > > +	unsigned int vring_align,
> > > +	struct virtio_device *vdev,
> > > +	bool weak_barriers,
> > > +	bool may_reduce_num,
> > > +	bool context,
> > > +	bool (*notify)(struct virtqueue *),
> > > +	void (*callback)(struct virtqueue *),
> > > +	const char *name)
> > > +{
> > > +	struct vring_virtqueue *vq;
> > > +	struct vring_packed vring;
> > > +
> > > +	if (vring_create_vring_packed(&vring, vdev, num))
> > > +		goto err_vq;
> > >
> > >   	vq = kmalloc(sizeof(*vq), GFP_KERNEL);
> > >   	if (!vq)
> > > @@ -1753,17 +1821,17 @@ static struct virtqueue *vring_create_virtqueue_packed(
> > >   	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
> > >   		vq->weak_barriers = false;
> > >
> > > -	vq->packed.ring_dma_addr = ring_dma_addr;
> > > -	vq->packed.driver_event_dma_addr = driver_event_dma_addr;
> > > -	vq->packed.device_event_dma_addr = device_event_dma_addr;
> > > +	vq->packed.ring_dma_addr = vring.ring_dma_addr;
> > > +	vq->packed.driver_event_dma_addr = vring.driver_event_dma_addr;
> > > +	vq->packed.device_event_dma_addr = vring.device_event_dma_addr;
> > >
> > > -	vq->packed.ring_size_in_bytes = ring_size_in_bytes;
> > > -	vq->packed.event_size_in_bytes = event_size_in_bytes;
> > > +	vq->packed.ring_size_in_bytes = vring.ring_size_in_bytes;
> > > +	vq->packed.event_size_in_bytes = vring.event_size_in_bytes;
> > >
> > >   	vq->packed.vring.num = num;
> > > -	vq->packed.vring.desc = ring;
> > > -	vq->packed.vring.driver = driver;
> > > -	vq->packed.vring.device = device;
> > > +	vq->packed.vring.desc = vring.ring;
> > > +	vq->packed.vring.driver = vring.driver;
> > > +	vq->packed.vring.device = vring.device;
> > >
> > >   	vq->packed.next_avail_idx = 0;
> > >   	vq->packed.avail_wrap_counter = 1;
> > > @@ -1804,12 +1872,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
> > >   err_desc_state:
> > >   	kfree(vq);
> > >   err_vq:
> > > -	vring_free_queue(vdev, event_size_in_bytes, device, device_event_dma_addr);
> > > -err_device:
> > > -	vring_free_queue(vdev, event_size_in_bytes, driver, driver_event_dma_addr);
> > > -err_driver:
> > > -	vring_free_queue(vdev, ring_size_in_bytes, ring, ring_dma_addr);
> > > -err_ring:
> > > +	vring_free_vring_packed(&vring, vdev);
> > >   	return NULL;
> > >   }
> > >
> > > --
> > > 2.31.0