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Re: [XEN][PATCH 0/8] xen/arm64: make aarch32 support optional
- To: Julien Grall <julien@xxxxxxx>, "Orzel, Michal" <michal.orzel@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- From: Grygorii Strashko <grygorii_strashko@xxxxxxxx>
- Date: Thu, 24 Jul 2025 17:24:22 +0300
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- Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>, Bertrand Marquis <bertrand.marquis@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Anthony PERARD <anthony.perard@xxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxx>, Roger Pau Monne <roger.pau@xxxxxxxxxx>
- Delivery-date: Thu, 24 Jul 2025 14:24:37 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
Hi All,
On 23.07.25 15:12, Grygorii Strashko wrote:
On 23.07.25 15:02, Julien Grall wrote:
Hi,
On 23/07/2025 12:48, Grygorii Strashko wrote:
On 23.07.25 13:54, Orzel, Michal wrote:
On 23/07/2025 10:06, Julien Grall wrote:
On 23/07/2025 08:58, Grygorii Strashko wrote:
From: Grygorii Strashko <grygorii_strashko@xxxxxxxx>
Hi,
Hi Grygorii,
Now Arm64 AArch32 guest support is always enabled and built-in while not
all Arm64 platforms supports AArch32 or this support might not be needed.
I am not entirely sure I like the proliferation of using CONFIG_* for
every single feature. This makes the testing a bit more complicated.
Can you clarify what the goal with this patch?
AArch32 is used quite rarely in embedded systems. Also, in Armv9A it might only
be implemented at EL0 if at all. When focusing on safety certification, AArch32
related code in Xen leaves a gap in terms of coverage that cannot really be
justified in words. This leaves us with two options: either support it (lots of
additional testing, requirements and documents would be needed) or compile it
out.
FYI. bloat-o-meter report for this series with CONFIG_ARM64_AARCH32=n,
CONFIG_EXPERT=y
Thanks for sharing the bloat-o-meter. But I don't think the result below
warrant a new config.
The reason provided by Michal is a better reason as the impact on safety
certification is more significant.
It just an additional info to illustrate achieved build-time optimization
results
which reduces coverage gaps.
Would it be reasonable to send patches which split arm64/arm32 code separately
(Patches 1,3,4,7)?
(with comments applied).
--
Best regards,
-grygorii
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