From: Ayan Kumar Halder <ayankuma@amd.com>
To: Julien Grall <julien@xen.org>,
"Stabellini, Stefano" <stefano.stabellini@amd.com>,
bertrand Marquis <Bertrand.Marquis@arm.com>,
"Volodymyr_Babchuk@epam.com" <Volodymyr_Babchuk@epam.com>,
Henry Wang <Henry.Wang@arm.com>,
Penny Zheng <Penny.Zheng@arm.com>
Cc: Jaxson Han <jaxson.han@arm.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Need guidance to support reading GICR_TYPER (64 bit register) on Aarch32_v8r
Date: Thu, 13 Oct 2022 12:47:39 +0100 [thread overview]
Message-ID: <e2d041b2-3b38-f19b-2d8e-3a255b0ac07e@amd.com> (raw)
Hi Arm mantainers/Folks,
Please refer to the discussion
https://github.com/zephyrproject-rtos/zephyr/pull/51163 .
We intend to run Zephyr as a domU guest on Xen on Aarch32_v8R fixed
virtual platform.
Zephyr is trying to read GICR_TYPER which is a 64 bit register using
ldrd instruction.
As GICR is emulated by Xen, so this instruction gets trapped with HSR =
0x9200000c.
As ISV is 0, so Xen cannot emulate this instruction.
The proposed solution is to use two sys_read32() on GICR_TYPER to return
the lower and upper 32 bits.
With this, HSR = 0x9383 000c, ISV=1 so ISS is valid.
Now, for Xen to emulate this read, I have proposed the modifications (in
my last comment).
1. Does the proposed modifications look sane ? Or could there be a
better alternative ?
2. As there is no 32 bit variant for GICR_TYPER, so does it make sense
to read this register at all ?
Kind regards,
Ayan
next reply other threads:[~2022-10-13 11:48 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-13 11:47 Ayan Kumar Halder [this message]
2022-10-13 13:20 ` Need guidance to support reading GICR_TYPER (64 bit register) on Aarch32_v8r Julien Grall
2022-10-13 14:30 ` Ayan Kumar Halder
2022-10-13 14:47 ` Julien Grall
2022-10-13 15:13 ` Ayan Kumar Halder
2022-10-13 15:38 ` Julien Grall
2022-10-13 16:05 ` Ayan Kumar Halder
2022-10-13 16:23 ` Julien Grall
2022-10-14 18:09 ` Stefano Stabellini
2022-10-15 9:28 ` Julien Grall
2022-10-17 9:17 ` Bertrand Marquis
2022-10-17 9:27 ` Julien Grall
2022-10-17 9:52 ` Bertrand Marquis
2022-10-17 9:50 ` Bertrand Marquis
2022-10-17 10:22 ` Bertrand Marquis
2022-10-18 1:26 ` Stefano Stabellini
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