Messages in this thread | | | Date | Wed, 5 Aug 2020 08:55:27 -0400 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH 3/4] vdpa: get_iova_range() is mandatory for device specific DMA translation |
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On Wed, Jun 17, 2020 at 11:29:46AM +0800, Jason Wang wrote: > In order to let userspace work correctly, get_iova_range() is a must > for the device that has its own DMA translation logic.
I guess you mean for a device.
However in absence of ths op, I don't see what is wrong with just assuming device can access any address.
> > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > drivers/vdpa/vdpa.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c > index de211ef3738c..ab7af978ef70 100644 > --- a/drivers/vdpa/vdpa.c > +++ b/drivers/vdpa/vdpa.c > @@ -82,6 +82,10 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent, > if (!!config->dma_map != !!config->dma_unmap) > goto err; > > + if ((config->dma_map || config->set_map) && > + !config->get_iova_range) > + goto err; > + > err = -ENOMEM; > vdev = kzalloc(size, GFP_KERNEL); > if (!vdev)
What about devices using an IOMMU for translation? IOMMUs generally have a limited IOVA range too, right?
> -- > 2.20.1
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