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Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , "Michael Kelley (EOSG)" , "kvm@vger.kernel.org" , Paolo Bonzini , =?utf-8?B?UmFkaW0gS3LEjW3DocWZ?= , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , Roman Kagan Content-Transfer-Encoding: quoted-printable Message-Id: References: <20181126154732.23025-1-vkuznets@redhat.com> <20181126154732.23025-2-vkuznets@redhat.com> <20181126200413.GA7852@rkaganb.sw.ru> <87wooyk6na.fsf@vitty.brq.redhat.com> <20181127184835.GA5147@rkaganip.lan> <8A215F49-BB8F-4E93-AC62-EC33B4734F24@gmail.com> <87a7ltjxnz.fsf@vitty.brq.redhat.com> To: Thomas Gleixner , Vitaly Kuznetsov X-Mailer: Apple Mail (2.3445.101.1) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Nov 28, 2018, at 5:07 AM, Thomas Gleixner = wrote: >=20 > On Wed, 28 Nov 2018, Vitaly Kuznetsov wrote: >=20 >> Nadav Amit writes: >>=20 >>> On a different note: how come all of the hyper-v structs are not = marked >>> with the =E2=80=9Cpacked" attribute? >>=20 >> "packed" should not be needed with proper padding; I vaguely remember >> someone (from x86@?) arguing _against_ "packed". >=20 > 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. >=20 > 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.