Re: [PATCH 3/4] vdpa: get_iova_range() is mandatory for device specific DMA translation
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2020-08-05 17:21:53
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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.
quoted hunk ↗ jump to hunk
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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