Hi Michal,
On 18/02/2026 08:36, Orzel, Michal wrote:
But that's not correct for cases where share_xen_page_with_privileged_guest()
is passed SHARE_ro. XENMAPSPACE_gmfn_foreign requests have to result in r/o
mappings in that case.
Yes. Therefore, on Arm:
- p2m_ram_ro is never stored in P2M tables for normal domains
p2m_set_permission() is able to deal with p2m_ram_ro. So this could in
theory happen.
- it's only used by get_page_from_gfn() for DOMID_XEN pages
- it's used as a signal to install p2m_map_foreign_ro mappings
The code should stay as is then and we could modify the comment to say:
> /* Read-only RAM; only used for DOMID_XEN */
With what I wrote above, I don't think we should add such comment.
Cheers,
--
Julien Grall
