Re: [PATCH RFC] xen-block: correctly define structures in publicheaders

From: David Vrabel
Date: Tue Dec 03 2013 - 06:01:37 EST


On 03/12/13 10:57, Roger Pau Monne wrote:
> Using __packed__ on the public interface is not correct, this
> structures should be compiled using the native ABI, and __packed__
> should only be used in the backend counterpart of those structures
> (which needs to handle different ABIs).
>
> This was even worse in the ARM case, where the Linux kernel was
> incorrectly using the X86_32 protocol ABI. This patch fixes it, but
> also breaks compatibility, so an ARM DomU kernel compiled with
> this patch will fail to communicate with PV disk devices unless the
> Dom0 also has this patch.

This ABI change needs to be justified. Why do you think it is
acceptable to break existing Linux guests? Because I don't think it is.

David
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