Re: [Xen-devel] [PATCH v2] xen/block: Correctly define structures in public headers on ARM32 and ARM64

[David Vrabel <david.vrabel@xxxxxxxxxx>]

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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