Hi, Rob
On 03/18/2017 02:22 PM, Rob Clark wrote:
On Fri, Mar 17, 2017 at 1:39 PM, Oleksandr Andrushchenko
<andr2000@xxxxxxxxx> wrote:
Hello,
I am writing a para-virtualized DRM driver for Xen hypervisor
and it now works with DRM CMA helpers, but I would also like
to make it work with non-contigous memory: virtual machine
that the driver runs in can't guarantee that CMA is actually
physically contigous (that is not a problem because of IPMMU
and other means, the only constraint I have is that I cannot mmap
with pgprot == noncached). So, I am planning to use *drm_gem_get_pages* +
*shmem_read_mapping_page_gfp* to allocate memory for GEM objects
(scanout buffers + dma-bufs shared with virtual GPU)
Do you think this is the right approach to take?
I guess if you had some case where you needed to "migrate" buffers
between host and guest memory,
yes, this is the case. but, I can "map" buffers between host and guests
then TTM might be useful.
I was looking into it, but it seems to be an overkill in my case
And isn't it that GEM should be used for new drivers, not TTM?
Otherwise
this sounds like the right approach.
Thank you. Actually, I am playing with alloc_pages + remap_pfn_range now,
but what DRM provides (_get_pages + shmem_read) seem to be more portable
and generic. So, I'll probably stick to it
BR,
-R
Thank you for helping,
Oleksandr Andrushchenko
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
