[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [PATCH 3/7] xen/arm64: head: Add missing isb in setup_fixmap()
- To: Julien Grall <julien@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- From: Henry Wang <Henry.Wang@xxxxxxx>
- Date: Tue, 20 Jun 2023 03:06:53 +0000
- Accept-language: zh-CN, en-US
- Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none
- Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; 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=iQvsWGMcUsWsCUgqcEUW5ONcfXrYVIDEyG9/G794PDE=; b=lEqOh+AopRONdVxH1mofTtqTXG6eP3XHmig9V1Fq9UeoHc8nevQaScmjicdVrNlMYBu1QztkTzc0ZgcNIIItisdnBILwVbEgfEoLJJFhFDXahDpYsTyzC6Ce0JxhL9MpuvUyUngz45zvx2iilEOZ4bYbEXGkqQp/u2edy9Qyiit2wPRMNLsAlGCU6V/pdio7gSjy7QYUfrVPL8adqJbLaH3k9ryPOXkoMpeq/gwPz08jr75zWUZNnywWjmBwsSZAkvQ+Mz95VioIaKKxoaYMLQ/5CzBSCKugkhlRb0zTC6JCmAS+V1VuBdlDUb2qk2Ar3DDrqzd08ajGC2Bc7En2lw==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=BiusLp9pzDaYeCN/+bdaZAF3hNRrh5+JhDzPwbVwqGqvc8h3Z/B3JjBUXAtVnWxyocz5xHEGVN7PGXmunkakD50c/J695CTrP15T3Da+IqjEdHYqprv7w5Zc7EiO8X5JwV8vtcBe+xuDoveayT4/aVmWJK4l5zs9eVG6P4yoOmujmTpEYB19UBcGGALj0SNHEUMWNpGoPhVXdfFlimcoWFlK8aGZMfhsnTdBs1uDZPhe8Pwbcbr8DfRKyhpqwpgt6Ean4Yk/sURJTiuLIjKUioxkm8i6RnKMv6adc5QJrEM6aoh8fWvBOAYXvmED8hfaKPCa60V11Lnk79cA7wdQYA==
- Authentication-results-original: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com;
- Cc: Luca Fancellu <Luca.Fancellu@xxxxxxx>, "michal.orzel@xxxxxxx" <michal.orzel@xxxxxxx>, Julien Grall <jgrall@xxxxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Bertrand Marquis <Bertrand.Marquis@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
- Delivery-date: Tue, 20 Jun 2023 03:07:08 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
- Nodisclaimer: true
- Original-authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com;
- Thread-index: AQHZos+3tMp+ZtyHWUyoGXqmHpGIuK+S1Uuw
- Thread-topic: [PATCH 3/7] xen/arm64: head: Add missing isb in setup_fixmap()
Hi Julien,
> -----Original Message-----
> Subject: [PATCH 3/7] xen/arm64: head: Add missing isb in setup_fixmap()
>
> From: Julien Grall <jgrall@xxxxxxxxxx>
>
> On older version of the Arm Arm (ARM DDI 0487E.a, B2-125) there were
> the following paragraph:
>
> "DMB and DSB instructions affect reads and writes to the memory system
> generated by Load/Store instructions and data or unified cache
> maintenance instructions being executed by the PE. Instruction fetches
> or accesses caused by a hardware translation table access are not
> explicit accesses."
>
> Newer revision (e.g. ARM DDI 0487J.a) doesn't have the second sentence
> (it might be somewhere else in the Arm Arm). But the interpretation is
> not much different.
>
> In setup_fixmap(), we write the fixmap area and may be used soon after,
> for instance, to write to the UART. IOW, there could be hardware
> translation table access. So we need to ensure the 'dsb' has completed
> before continuing. Therefore add an 'isb'.
>
> Fixes: 2b11c3646105 ("xen/arm64: head: Remove 1:1 mapping as soon as it is
> not used")
> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
Reviewed-by: Henry Wang <Henry.Wang@xxxxxxx>
I've also tested this patch on top of today's staging by our internal CI, which
includes some arm64 emulated platforms and also real hardware, and this patch
looks good, so:
Tested-by: Henry Wang <Henry.Wang@xxxxxxx>
Kind regards,
Henry
|
