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Re: [PATCH v4 1/7] docs/arm: Document Xen booting protocol on Armv8-R
- To: Luca Fancellu <luca.fancellu@xxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
- From: Ayan Kumar Halder <ayankuma@xxxxxxx>
- Date: Tue, 29 Apr 2025 18:11:00 +0100
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- Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, Bertrand Marquis <bertrand.marquis@xxxxxxx>, Michal Orzel <michal.orzel@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
- Delivery-date: Tue, 29 Apr 2025 17:11:14 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
Hi Luca,
On 29/04/2025 16:20, Luca Fancellu wrote:
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Document the requirement needed to boot Xen on Armv8-R platforms.
Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
Reviewed-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
---
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
--
2.34.1
- Ayan
|
