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Date: Thu, 12 Dec 2013 16:11:59 +0100
From: =?UTF-8?B?Um9nZXIgUGF1IE1vbm7DqQ==?= <roger.pau@citrix.com>
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To: Ian Campbell <Ian.Campbell@citrix.com>,
        Julien Grall <julien.grall@linaro.org>
CC: <xen-devel@lists.xenproject.org>,
        Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
        <linux-kernel@vger.kernel.org>, David Vrabel <david.vrabel@citrix.com>,
        <patches@linaro.org>, Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        <linux-arm-kernel@lists.infradead.org>
Subject: Re: [Xen-devel] [PATCH v2] xen/block: Correctly define structures
 in public headers on ARM32 and ARM64
References: <1386085237-8334-1-git-send-email-julien.grall@linaro.org> <1386857960.11201.57.camel@kazak.uk.xensource.com>
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On 12/12/13 15:19, Ian Campbell wrote:
> On Tue, 2013-12-03 at 15:40 +0000, Julien Grall wrote:
>> On ARM (32 bits and 64 bits), the double-word is 8-bytes aligned. This will
>> result on different structure from Xen and Linux repositories.
>>
>> As Linux is using __packed__ attribute, it must have a 4-bytes padding before
>> each "id" field.
>>
>> This change breaks guest block support with older kernel. IMHO, it's acceptable
>> because Xen on ARM is still on Tech Preview and the hypercall ABI is not yet
>> freezed.
>>
>> Only one architecture (x86_32) doesn't have 64-bit ABI for the block interface.
>> Don't add padding if Linux is compiled for this architecture.
> 
> Konrad asked for confirmation that this didn't change x86.

I've also tested this using various combinations of kernels, and it
seems to be perfectly fine, so:

Acked-by: Roger Pau Monné <roger.pau@citrix.com>