Re: [PATCH v2] xen/block: Correctly define structures in public headerson ARM32 and ARM64

From: David Vrabel
Date: Tue Dec 03 2013 - 12:10:58 EST


On 03/12/13 15:40, 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.

I'm now satisfied that this is the right thing to do.

Acked-by: David Vrabel <david.vrabel@xxxxxxxxxx>

David
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