[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH 5/5] xen/arm: map static memory on demand
- To: Hari Limaye <Hari.Limaye@xxxxxxx>, "Orzel, Michal" <michal.orzel@xxxxxxx>
- From: Ayan Kumar Halder <ayankuma@xxxxxxx>
- Date: Wed, 27 Aug 2025 14:30:31 +0100
- Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=arm.com smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0)
- Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=Vbf0In1LnKfwEYSPb8BqJXhdDpOjyfrFv4TtDjUmTjg=; b=bD+kw3edNGk/gKf/coqipUw26gY7EoWnD9x5tQxh2Yc9avhKH5/lRUns5cp/UFRhdfIwrgJloyPQzDUAz6iMAdQ2JMuGorzTdrOgkamv002xe0gg+N7aTFwo56RG1Grf311Z88rCYvSsO+j60OCQaLgmQ2AhF5xsvma9p1T6QLRIQVXdbS/jqfuhAvy1EuQY/SpBo2lG2YEXdZu6jnrLKqt60Zku5dqAZCEizfecMLA5IGDKQkOG2eLkvQxnT75cGF0br+XHzTl4LmiyxF0Pp9Dy9r1l83wYYXMFCDrB+JkRtOLI0nCAuvWlGA/m6d4/P2pXkz3X6tuij2qIlAPFFA==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=jm6DPZWSj5x135IPaoLKOrmpP4keOju77pCMDNqU/L3ZC949wLWI05gx+Q828z4UAo69gJBibAfTTn0uZLgEvZedPBpTwJwLOEfgEsDZ7kycAkdbw0aoDA5L0ljzQjxQEIf2rrWYv0kZ0OeUY4J3pwAM/bwGCI4oDVWLhfyIbqoIbJN4i3kEv+4jXlYy1kufuG41cpIHRPLyEI7KPNh/Ean5gB0wPxXHtnUz1PE8Ndka6LjIjSKpr2Zd1NFM8o9OpYpqyM2Y1M9BCWr72Yt+MSJY3lAsIPUS4PORLOg3Z/JhM7AXIrxsgVFE38NusPzCx22+T0Cr8HeUMdQACIadqQ==
- Cc: "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>, "Luca Fancellu" <Luca.Fancellu@xxxxxxx>, Penny Zheng <Penny.Zheng@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, 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 Monné <roger.pau@xxxxxxxxxx>, Wei Chen <Wei.Chen@xxxxxxx>
- Delivery-date: Wed, 27 Aug 2025 13:30:56 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 27/08/2025 13:31, Hari Limaye wrote:
CAUTION: This message has originated from an External Source. Please use proper
judgment and caution when opening attachments, clicking links, or responding to
this email.
Hi Michal,
Hi Hari, Michal,
On 22 Aug 2025, at 08:50, Orzel, Michal <michal.orzel@xxxxxxx> wrote:
On 30/07/2025 10:45, Hari Limaye wrote:
From: Penny Zheng <Penny.Zheng@xxxxxxx>
In the function `init_staticmem_pages` we need to have mapped static
memory banks for initialization. Unlike on an MMU system, we cannot map
the entire RAM on an MPU system as we have a limited number of MPU
memory regions. To solve this, transiently map the static memory banks
for initialization.
How does this correspond to Arm32 MPU (R52), where all of the RAM will be
covered? I don't think 'transient' mappings will be needed there but all of your
work targets common (i.e. not only Arm64) MPU code.
~Michal
Hm fair point - when this series was submitted to the ML, I had no knowledge of
the intention for all of the RAM to be mapped on Arm32 MPU systems and imagined
that things would be more aligned here.
Are happy for this to remain common for now? Or would you prefer it to be split
off?
Let's split here between Arm_32 and Arm_64.
As discussed on Matrix, for Arm_32 we are mapping the entire static
memory as a permanent MPU region. In light of Julien's comments and
Alejandro's patch, I will revisit the approach in some time.
However, I don't want to create a dependency for this series.
We can realign later if needed. :)
- Ayan
Many thanks,
Hari
|
