On 21 September 2018 at 10:46, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > On Fri, 21 Sep 2018 18:14:43 +0100, > Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx> wrote: >> >> On 9/21/2018 10:32 AM, Ard Biesheuvel wrote: >> > Add support for persistent memory reservations across kexec reboot on EFI >> > systems by introducing a Linux-specific UEFI configuration table that points >> > to a linked list in memory that can be augmented by each successive kexec >> > kernel to describe regions in memory that the subsequent kernel should treat >> > as reserved. >> > >> > The specific use case for this feature is GICv3 ARM systems that are not >> > able to disable DMA access to LPI tables, meaning we have to reserve them >> > and make the next kernel reuse the existing tables rather than allocating >> > them from scratch. >> >> As far as I recall, Shanker Donthineni attempted to address a similar >> (the same?) issue. I think we would be very interested, if that is >> the case. > > Shanker's patches didn't solve the story of preserving the allocated > memory across kexec, and were just expecting to get similar mappings. > > Ard's patches allow us to track the allocation, and to reuse those if > it is safe to do so. > >> Is there another series that depends on these changes? If not, can >> you describe the plan for this? > > I have a series which does exactly that[1], and that rely on Ard's > patches. I'm about to post these patches now the dependency is public. > FYI the efi_reserve_mem_region() function has been renamed to efi_mem_reserve_persistent()
