lkml.org 
[lkml]   [2020]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectDMA, TTM and memory encryption
Date
Hi, Christoph,

It would be good to revisit this to see if we could set a direction for
supporting user-space mapping of dma-coherent memory with TTM.

I think in the end, what TTM needs is a DMA interface similar to the one
outlined here:

https://lore.kernel.org/lkml/b811f66d-2353-23c6-c9fa-e279cdb0f832@shipmail.org/

That could without too much effort be implemented for all architectures
TTM supports and also for those weird architectures you've described
that need special treatment, it would probably suffice with a more
elaborate definition of the dma_pfn_t together with the dma coherent
fault work you were suggesting earlier.

Regardless, once this patchset is in,

https://lore.kernel.org/lkml/20200304114527.3636-1-thomas_os@shipmail.org/

a short term solution would be to export the dma_pgprot() function and
have TTM use it to set the pgprot for dma-coherent memory.

What do you think about this?

Thanks,

Thomas


\
 
 \ /
  Last update: 2020-03-16 16:25    [W:0.037 / U:5.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site