Re: [PATCH v2 00/11] Remove device private pages from physical address space

Balbir Singh
2026-01-07T21:02:38Z

On 1/8/26 06:54, Jason Gunthorpe wrote:
> On Wed, Jan 07, 2026 at 12:06:08PM -0800, Andrew Morton wrote:
>
>>> 2) Attempting to add the device private pages to the linear map at
>>> addresses beyond the actual physical memory causes issues on
>>> architectures like aarch64 - meaning the feature does not work there [0].
>>
>> Can you better help us understand the seriousness of these problems?
>> How much are our users really hurting from this?
>
> We think it is pretty serious, in the future HW support sense, as it
> means real systems being built do not work :)
>
> Also Willy and others were cheering this work on at LPC. I think the
> possible followup to move DEVICE_PRIVATE from struct page and reduce
> the memory allocation would be well celebrated.
>
> The Intel Xe and AMD GPU teams are the two drivers most important to
> be testing this as they consume the feature.
>

And the ultravisor usage in powerpc as well (book3s_hv_uvmem).

Balbir