[Intel-gfx] [PATCH v12 18/24] vfio: Add VFIO_DEVICE_BIND_IOMMUFD

[Alex Williamson]

On Tue, 13 Jun 2023 14:42:46 +0000
"Liu, Yi L" <yi.l.liu at intel.com> wrote:

> > From: Alex Williamson <alex.williamson at redhat.com>
> > Sent: Tuesday, June 13, 2023 10:40 PM
> > 
> > On Tue, 13 Jun 2023 14:28:43 +0000
> > "Liu, Yi L" <yi.l.liu at intel.com> wrote:
> >   
> > > > From: Alex Williamson <alex.williamson at redhat.com>
> > > > Sent: Tuesday, June 13, 2023 10:18 PM  
> > >  
> > > > > > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> > > > > > > index 83cc5dc28b7a..e80a8ac86e46 100644
> > > > > > > --- a/include/linux/vfio.h
> > > > > > > +++ b/include/linux/vfio.h
> > > > > > > @@ -66,6 +66,7 @@ struct vfio_device {
> > > > > > >  	struct iommufd_device *iommufd_device;
> > > > > > >  	bool iommufd_attached;
> > > > > > >  #endif
> > > > > > > +	bool cdev_opened:1;  
> > > > > >
> > > > > > Perhaps a more strongly defined data type here as well and roll
> > > > > > iommufd_attached into the same bit field scheme.  
> > > > >
> > > > > Ok, then needs to make iommufd_attached always defined.  
> > > >
> > > > That does not follow.  Thanks,  
> > >
> > > Well, I meant the iommufd_attached now is defined only when
> > > CONFIG_IOMMUFD is enabled. To toll it with cdev_opened, needs
> > > to change this.  
> > 
> > Understood, but I don't think it's true.  If defined we use one more
> > bit of the bit field, which is a consideration when we approach filling
> > it, but we're not using bit-shift operations to address these bits, so
> > why does it matter if one has compiler conditional usage?  Thanks,  
> 
> Aha, I see. So you are suggesting something like the below. Is it?
> 
> #if IS_ENABLED(CONFIG_IOMMUFD)
> 	struct iommufd_device *iommufd_device;
> 	u8 iommufd_attached:1;
> #endif
> 	u8 cdev_opened:1;


Precisely.  Thanks,

Alex