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Date:   Thu, 12 May 2022 09:47:26 -0300
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Abhishek Sahu <abhsahu@nvidia.com>
Cc:     Alex Williamson <alex.williamson@redhat.com>,
        Cornelia Huck <cohuck@redhat.com>,
        Yishai Hadas <yishaih@nvidia.com>,
        Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>,
        Kevin Tian <kevin.tian@intel.com>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Max Gurtovoy <mgurtovoy@nvidia.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-pm@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH v3 8/8] vfio/pci: Add the support for PCI D3cold state
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On Thu, May 12, 2022 at 05:57:05PM +0530, Abhishek Sahu wrote:
> On 5/10/2022 7:00 PM, Jason Gunthorpe wrote:
> > On Tue, May 10, 2022 at 06:56:02PM +0530, Abhishek Sahu wrote:
> >>> We can add a directive to enforce an alignment regardless of the field
> >>> size.  I believe the feature ioctl header is already going to be eight
> >>> byte aligned, so it's probably not strictly necessary, but Jason seems
> >>> to be adding more of these directives elsewhere, so probably a good
> >>> idea regardless.  Thanks,
> > 
> >> So, should I change it like
> >>
> >> __u8    low_power_state __attribute__((aligned(8)));
> >>
> >>  Or
> >>
> >> __aligned_u64 low_power_state
> > 
> > You should be explicit about padding, add a reserved to cover the gap.
> > 
> > Jasno
> 
> 
>  Thanks Jason.
> 
>  So, I need to make it like following. Correct ?
> 
>  __u8 low_power_state;
>  __u8 reserved[7];
> 
>  It seems, then this aligned attribute should not be required.

Yes

Jason