Re: [PATCH v2 1/4] x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h

From: Thomas Gleixner
Date: Wed Nov 28 2018 - 08:07:56 EST

On Wed, 28 Nov 2018, Vitaly Kuznetsov wrote:

> Nadav Amit <nadav.amit@xxxxxxxxx> writes:
> >
> > On a different note: how come all of the hyper-v structs are not marked
> > with the âpacked" 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

Using packed for generic data structures might result in suboptimal layouts
and prevents layout randomization.