From 7d59c1a9189549283654cd68892f7122cdd8fd14 Mon Sep 17 00:00:00 2001 From: Dirk Behme Date: Mon, 25 Apr 2016 17:42:54 +0200 Subject: [PATCH] xen: arm: doc: Add firmware requirements Add a section about what the firmware should do in EL3 before starting Xen. E.g guest will use HVC instruction to issue hypercall. As this can be set only at EL3, i.e. outside Xen, document this boot requirement. Signed-off-by: Dirk Behme Reviewed-by: Stefano Stabellini --- docs/misc/arm/booting.txt | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/docs/misc/arm/booting.txt b/docs/misc/arm/booting.txt index 9802e5e20f..c7c1d7ea58 100644 --- a/docs/misc/arm/booting.txt +++ b/docs/misc/arm/booting.txt @@ -23,6 +23,17 @@ The exceptions to this on 32-bit ARM are as follows: There are no exception on 64-bit ARM. + +Firmware/bootloader requirements +-------------------------------- + +Xen relies on some settings the firmware has to configure in EL3 before starting Xen. + +* Xen must be entered in NS EL2 mode + +* The bit SCR_EL3.HCR (resp. SCR.HCE for 32-bit ARM) must be set to 1. + + [1] linux/Documentation/arm/Booting Latest version: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/arm/Booting -- 2.30.2