[Nouveau] [PATCH] nouveau/hmm: map pages after migration

[Christoph Hellwig]

On Mon, Aug 12, 2019 at 12:42:30PM -0700, Ralph Campbell wrote:
>
> On 8/10/19 4:13 AM, Christoph Hellwig wrote:
>> On something vaguely related to this patch:
>>
>> You use the NVIF_VMM_PFNMAP_V0_V* defines from nvif/if000c.h, which are
>> a little odd as we only ever set these bits, but they also don't seem
>> to appear to be in values that are directly fed to the hardware.
>>
>> On the other hand mmu/vmm.h defines a set of NVIF_VMM_PFNMAP_V0_*
>
> Yes, I see NVKM_VMM_PFN_*
>
>> constants with similar names and identical values, and those are used
>> in mmu/vmmgp100.c and what appears to finally do the low-level dma
>> mapping and talking to the hardware.  Are these two sets of constants
>> supposed to be the same?  Are the actual hardware values or just a
>> driver internal interface?
>
> It looks a bit odd to me too.
> I don't really know the structure/history of nouveau.
> Perhaps Ben Skeggs can shed more light on your question.

Ben, do you have any insights on these constants?