On Wed, Oct 16, 2024 at 07:49:31PM -0400, Peter Xu wrote:
On Wed, Oct 16, 2024 at 07:51:57PM -0300, Jason Gunthorpe wrote:
On Wed, Oct 16, 2024 at 04:16:17PM -0400, Peter Xu wrote:
Is there chance that when !CoCo will be supported, then external modules (e.g. VFIO) can reuse the old user mappings, just like before gmemfd?
To support CoCo, I understand gmem+offset is required all over the places. However in a non-CoCo context, I wonder whether the other modules are required to stick with gmem+offset, or they can reuse the old VA ways, because how it works can fundamentally be the same as before, except that the folios now will be managed by gmemfd.
My intention with iommufd was to see fd + offest as the "new" way to refer to all guest memory and discourage people from using VMA handles.
Does it mean anonymous memory guests will not be supported at all for iommufd?
No, they can use the "old" way with normal VMA's still, or they can use an anonymous memfd with the new way..
I just don't expect to have new complex stuff built on the VMA interface - I don't expect guestmemfd VMAs to work.
Jason