On Thu, Nov 24, 2022 at 09:59:25AM +0100, Roger Pau Monné wrote: > On Thu, Nov 24, 2022 at 06:15:15AM +0100, Marek Marczykowski-Górecki wrote: > > But to get dom0 display image from BGRT, it seems something else is > > needed too. Linux complains "Incorrect checksum in table [BGRT]". The > > only relevant google result I get is this: > > https://support.citrix.com/article/CTX460227/citrix-hypervisor-acpi-warning-incorrect-checksum-in-table-bgrt > > It blames firmware. But then, it's suspicious that it's also about Xen. > > And also, native Linux on the same hw does not complain about the > > checksum. So, I think it's rather Xen to blame... > > The table lives in area marked as EfiACPIReclaimMemory in memory map, so > > I think it shouldn't be clobbered by Xen, at least in theory. I'll look > > into it later. It's getting off-topic for this thread anyway. > > See commit 89238ef7797023f318f82f4f9dddef59c435b8bd. I wonder whether > the BGRT image region is marked as EFI_MEMORY_RUNTIME, I will have to > check on my system.
Just checked on my system, and the BGRT image is placed in a EfiBootServicesData section with no EFI_MEMORY_RUNTIME attribute. To fix this we would need to change efi_arch_process_memory_map() so it takes the BGRT image address into account and marks the region where it's placed as reserved. I'm not aware of anyway to get such address from EFI data, so we would likely need to parse the BGRT in efi_arch_process_memory_map(). Thanks, Roger.
