Hi Michal, > On 30 Apr 2025, at 07:37, Orzel, Michal <michal.or...@amd.com> wrote: > > > > On 29/04/2025 17:20, Luca Fancellu wrote: >> Document the requirement needed to boot Xen on Armv8-R platforms. >> >> Signed-off-by: Luca Fancellu <luca.fance...@arm.com> >> --- >> v4 changes: >> - New patch >> --- >> docs/misc/arm/booting.txt | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/docs/misc/arm/booting.txt b/docs/misc/arm/booting.txt >> index 21ae74837dcc..719af74f1e69 100644 >> --- a/docs/misc/arm/booting.txt >> +++ b/docs/misc/arm/booting.txt >> @@ -62,6 +62,14 @@ Xen relies on some settings the firmware has to configure >> in EL3 before starting >> >> * The bit SCR_EL3.HCE (resp. SCR.HCE for 32-bit ARM) must be set to 1. >> >> +When Xen runs on Armv8-R, the highest exception level is EL2 and the only >> +available state is secure (S) on Arm64 and non secure (NS) on Arm32, hence >> the >> +above requirements need to be adjusted to this case: >> + >> +* Xen must be entered in S EL2 mode on Arm64 and in NS EL2 mode on Arm32. >> + >> +* Xen must be entered with MPU off and data cache disabled (SCTLR_EL2.M bit >> and >> + SCTLR_EL2.C set to 0). >> >> [1] linux/Documentation/arm/booting.rst >> Latest version: >> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/arch/arm/booting.rst > > Is the goal of this patch to only write firmware/bootloader requirements or > accommodate booting protocol in general? Asking because in this file there is > a > requirement that Xen should be loaded below 10TB which afaict does not fit > Armv8-R.
Yes you are right, but I think this still holds since we support 1TB on Armv8-R at the moment? Cheers, Luca
