Re: [dpdk-dev] [PATCH 14/15] net/virtio: add vDPA op to get notification area

[Tiwei Bie <tiwei.bie@intel.com>]

On Tue, Sep 03, 2019 at 09:36:54AM +0200, Maxime Coquelin wrote:
> On 9/3/19 7:02 AM, Tiwei Bie wrote:
> > On Thu, Aug 29, 2019 at 09:59:59AM +0200, Maxime Coquelin wrote:
> >> This patch implements the vDPA .get_notify_area()
> >> callback.
> >>
> >> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> ---
> >>  drivers/net/virtio/virtio_vdpa.c | 33 ++++++++++++++++++++++++++++++++
> >>  1 file changed, 33 insertions(+)
> >>
> >> diff --git a/drivers/net/virtio/virtio_vdpa.c b/drivers/net/virtio/virtio_vdpa.c
> >> index e0b2f99ba..e681f527a 100644
> >> --- a/drivers/net/virtio/virtio_vdpa.c
> >> +++ b/drivers/net/virtio/virtio_vdpa.c
> >> @@ -707,6 +707,38 @@ virtio_vdpa_get_vfio_device_fd(int vid)
> >>  	return list->dev->vfio_dev_fd;
> >>  }
> >>  
> >> +static int
> >> +virtio_vdpa_get_notify_area(int vid, int qid, uint64_t *offset, uint64_t *size)
> >> +{
> >> +	int did;
> >> +	struct internal_list *list;
> >> +	struct virtio_vdpa_device *dev;
> >> +	struct vfio_region_info reg = { .argsz = sizeof(reg) };
> >> +	int ret;
> >> +
> >> +	did = rte_vhost_get_vdpa_device_id(vid);
> >> +	list = find_internal_resource_by_did(did);
> >> +	if (list == NULL) {
> >> +		DRV_LOG(ERR, "Invalid device id: %d", did);
> >> +		return -1;
> >> +	}
> >> +
> >> +	dev = list->dev;
> >> +
> >> +	reg.index = dev->hw.notify_region;
> >> +	ret = ioctl(dev->vfio_dev_fd, VFIO_DEVICE_GET_REGION_INFO, &reg);
> >> +	if (ret) {
> >> +		DRV_LOG(ERR, "Get not get device region info: %s",
> >> +				strerror(errno));
> >> +		return -1;
> >> +	}
> >> +
> >> +	*offset = dev->vqs[qid].notify_addr - dev->hw.notify_base + reg.offset;
> >> +	*size = 0x1000;
> > 
> > It would be better to check whether the size is no less
> > than 0x1000, otherwise it's possible to give guest the
> > access to other registers of the vdpa device.
> 
> Correct, if offset is not page-aligned, then it would mean one page may
> be mapped while not needed. I took the ifcvf driver as example and
> forgot to fix it. (Maybe it should also be fixed in ifcvf driver?)

The ifcvf hardware will make sure that the notify register will
stay in a separate page, so the size is hardcoded in ifcvf driver.

Regards,
Tiwei

> 
> Thanks,
> Maxime
> > Regards,
> > Tiwei
> > 
> >> +
> >> +	return 0;
> >> +}
> >> +
> >>  static struct rte_vdpa_dev_ops virtio_vdpa_ops = {
> >>  	.get_queue_num = virtio_vdpa_get_queue_num,
> >>  	.get_features = virtio_vdpa_get_features,
> >> @@ -716,6 +748,7 @@ static struct rte_vdpa_dev_ops virtio_vdpa_ops = {
> >>  	.set_features = virtio_vdpa_set_features,
> >>  	.get_vfio_group_fd = virtio_vdpa_get_vfio_group_fd,
> >>  	.get_vfio_device_fd = virtio_vdpa_get_vfio_device_fd,
> >> +	.get_notify_area = virtio_vdpa_get_notify_area,
> >>  };
> >>  
> >>  static inline int
> >> -- 
> >> 2.21.0
> >>