On Thu, Aug 06, 2020 at 11:29:16AM +0800, Jason Wang wrote:
>
> On 2020/8/5 下午8:58, Michael S. Tsirkin wrote:
> > On Wed, Jun 17, 2020 at 11:29:47AM +0800, Jason Wang wrote:
> > > This patch introduces a new ioctl for vhost-vdpa device that can
> > > report the iova range by the device. For device that depends on
> > > platform IOMMU, we fetch the iova range via DOMAIN_ATTR_GEOMETRY. For
> > > devices that has its own DMA translation unit, we fetch it directly
> > > from vDPA bus operation.
> > >
> > > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> > > ---
> > > drivers/vhost/vdpa.c | 27 +++++++++++++++++++++++++++
> > > include/uapi/linux/vhost.h | 4 ++++
> > > include/uapi/linux/vhost_types.h | 5 +++++
> > > 3 files changed, 36 insertions(+)
> > >
> > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> > > index 77a0c9fb6cc3..ad23e66cbf57 100644
> > > --- a/drivers/vhost/vdpa.c
> > > +++ b/drivers/vhost/vdpa.c
> > > @@ -332,6 +332,30 @@ static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp)
> > > return 0;
> > > }
> > > +
> > > +static long vhost_vdpa_get_iova_range(struct vhost_vdpa *v, u32 __user *argp)
> > > +{
> > > + struct iommu_domain_geometry geo;
> > > + struct vdpa_device *vdpa = v->vdpa;
> > > + const struct vdpa_config_ops *ops = vdpa->config;
> > > + struct vhost_vdpa_iova_range range;
> > > + struct vdpa_iova_range vdpa_range;
> > > +
> > > + if (!ops->set_map && !ops->dma_map) {
> > Why not just check if (ops->get_iova_range) directly?
>
>
> Because set_map || dma_ops is a hint that the device has its own DMA
> translation logic.
>
> Device without get_iova_range does not necessarily meant it use IOMMU
> driver.
>
> Thanks
OK let's add some code comments please, and check get_iova_range
is actually there before calling.
>
> >
> >
> >
> >
> > > + iommu_domain_get_attr(v->domain,
> > > + DOMAIN_ATTR_GEOMETRY, &geo);
> > > + range.start = geo.aperture_start;
> > > + range.end = geo.aperture_end;
> > > + } else {
> > > + vdpa_range = ops->get_iova_range(vdpa);
> > > + range.start = vdpa_range.start;
> > > + range.end = vdpa_range.end;
> > > + }
> > > +
> > > + return copy_to_user(argp, &range, sizeof(range));
> > > +
> > > +}
> > > +
> > > static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
> > > void __user *argp)
> > > {
> > > @@ -442,6 +466,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
> > > case VHOST_VDPA_SET_CONFIG_CALL:
> > > r = vhost_vdpa_set_config_call(v, argp);
> > > break;
> > > + case VHOST_VDPA_GET_IOVA_RANGE:
> > > + r = vhost_vdpa_get_iova_range(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 0c2349612e77..850956980e27 100644
> > > --- a/include/uapi/linux/vhost.h
> > > +++ b/include/uapi/linux/vhost.h
> > > @@ -144,4 +144,8 @@
> > > /* Set event fd for config interrupt*/
> > > #define VHOST_VDPA_SET_CONFIG_CALL _IOW(VHOST_VIRTIO, 0x77, int)
> > > +
> > > +/* Get the valid iova range */
> > > +#define VHOST_VDPA_GET_IOVA_RANGE _IOW(VHOST_VIRTIO, 0x78, \
> > > + struct vhost_vdpa_iova_range)
> > > #endif
> > > diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
> > > index 669457ce5c48..4025b5a36177 100644
> > > --- a/include/uapi/linux/vhost_types.h
> > > +++ b/include/uapi/linux/vhost_types.h
> > > @@ -127,6 +127,11 @@ struct vhost_vdpa_config {
> > > __u8 buf[0];
> > > };
> > > +struct vhost_vdpa_iova_range {
> > > + __u64 start;
> > > + __u64 end;
> > > +};
> > > +
> >
> > Pls document fields. And I think first/last is a better API ...
> >
> > > /* Feature bits */
> > > /* Log all write descriptors. Can be changed while device is active. */
> > > #define VHOST_F_LOG_ALL 26
> > > --
> > > 2.20.1
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