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SubjectRe: [PATCH v2 1/4] x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h
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> On Nov 28, 2018, at 5:07 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> On Wed, 28 Nov 2018, Vitaly Kuznetsov wrote:
>
>> Nadav Amit <nadav.amit@gmail.com> writes:
>>
>>> On a different note: how come all of the hyper-v structs are not marked
>>> with the “packed" attribute?
>>
>> "packed" should not be needed with proper padding; I vaguely remember
>> someone (from x86@?) arguing _against_ "packed".
>
> Packed needs to be used, when describing fixed format data structures in
> hardware or other ABIs, so the compiler cannot put alignment holes into
> them.
>
> Using packed for generic data structures might result in suboptimal layouts
> and prevents layout randomization.

Right, I forgot about the structs randomization. So at least for it, the
attribute should be needed.

To prevent conflicts, I think that this series should also add the
attribute in a first patch, which would be tagged for stable.

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