On Wed, Dec 23, 2020 at 4:37 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
>
> On 2020/12/22 下午10:52, Xie Yongji wrote:
> > This patch introduces a new method in the vdpa_config_ops to
> > support processing the raw vhost memory mapping message in the
> > vDPA device driver.
> >
> > Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
> > ---
> > drivers/vhost/vdpa.c | 5 ++++-
> > include/linux/vdpa.h | 7 +++++++
> > 2 files changed, 11 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> > index 448be7875b6d..ccbb391e38be 100644
> > --- a/drivers/vhost/vdpa.c
> > +++ b/drivers/vhost/vdpa.c
> > @@ -728,6 +728,9 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
> > if (r)
> > return r;
> >
> > + if (ops->process_iotlb_msg)
> > + return ops->process_iotlb_msg(vdpa, msg);
> > +
> > switch (msg->type) {
> > case VHOST_IOTLB_UPDATE:
> > r = vhost_vdpa_process_iotlb_update(v, msg);
> > @@ -770,7 +773,7 @@ static int vhost_vdpa_alloc_domain(struct vhost_vdpa *v)
> > int ret;
> >
> > /* Device want to do DMA by itself */
> > - if (ops->set_map || ops->dma_map)
> > + if (ops->set_map || ops->dma_map || ops->process_iotlb_msg)
> > return 0;
> >
> > bus = dma_dev->bus;
> > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> > index 656fe264234e..7bccedf22f4b 100644
> > --- a/include/linux/vdpa.h
> > +++ b/include/linux/vdpa.h
> > @@ -5,6 +5,7 @@
> > #include <linux/kernel.h>
> > #include <linux/device.h>
> > #include <linux/interrupt.h>
> > +#include <linux/vhost_types.h>
> > #include <linux/vhost_iotlb.h>
> > #include <net/genetlink.h>
> >
> > @@ -172,6 +173,10 @@ struct vdpa_iova_range {
> > * @vdev: vdpa device
> > * Returns the iova range supported by
> > * the device.
> > + * @process_iotlb_msg: Process vhost memory mapping message (optional)
> > + * Only used for VDUSE device now
> > + * @vdev: vdpa device
> > + * @msg: vhost memory mapping message
> > * @set_map: Set device memory mapping (optional)
> > * Needed for device that using device
> > * specific DMA translation (on-chip IOMMU)
> > @@ -240,6 +245,8 @@ struct vdpa_config_ops {
> > struct vdpa_iova_range (*get_iova_range)(struct vdpa_device *vdev);
> >
> > /* DMA ops */
> > + int (*process_iotlb_msg)(struct vdpa_device *vdev,
> > + struct vhost_iotlb_msg *msg);
> > int (*set_map)(struct vdpa_device *vdev, struct vhost_iotlb *iotlb);
> > int (*dma_map)(struct vdpa_device *vdev, u64 iova, u64 size,
> > u64 pa, u32 perm);
>
>
> Is there any reason that it can't be done via dma_map/dma_unmap or set_map?
>
To get the shmfd, we need the vma rather than physical address. And
it's not necessary to pin the user pages in VDUSE case.
Thanks,
Yongji
