[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [RFC] virtio_ring: check dma_mem for xen_domain



On Mon, Jan 21, 2019 at 04:51:57AM +0000, Peng Fan wrote:
> on i.MX8QM, M4_1 is communicating with DomU using rpmsg with a fixed
> address as the dma mem buffer which is predefined.
> 
> Without this patch, the flow is:
> vring_map_one_sg -> vring_use_dma_api
>                  -> dma_map_page
>                      -> __swiotlb_map_page
>                               ->swiotlb_map_page
>                               ->__dma_map_area(phys_to_virt(dma_to_phys(dev, 
> dev_addr)), size, dir);
> However we are using per device dma area for rpmsg, phys_to_virt
> could not return a correct virtual address for virtual address in
> vmalloc area. Then kernel panic.

And that is the right thing to do.  You must not call dma_map_* on
memory that was allocated from dma_alloc_*.

We actually have another thread which appears to be for this same issue.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel

 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.