Re: [RFC v2] virtio: add virtio-over-PCI driver

[Geert Uytterhoeven]

On Thu, 26 Feb 2009, Arnd Bergmann wrote:
> On Tuesday 24 February 2009, Ira Snyder wrote:
> > +/* Virtio-over-PCI descriptors: 12 bytes. These can chain together via "next" */
> > +struct vop_desc {
> > +	/* Address (host physical) */
> > +	__le32 addr;
               ^^^^
Only 32-bit? Is this future-proof?

> > +	/* Length (bytes) */
> > +	__le32 len;
> > +	/* Flags */
> > +	__le16 flags;
> > +	/* Chaining for descriptors */
> > +	__le16 next;
> > +} __attribute__((packed));
> 
> I would drop the "packed" attribute in the structure definitions.
> It would imply that only byte accesses are allowed on these
> data structures, because the attribute invalidates any assumptions
> about alignment. None of your structures require padding, so
> the attribute does not have any positive effect either.
> 
> > +/* MPC8349EMDS specific get_immrbase() */
> > +#include <sysdev/fsl_soc.h>
> 
> Do you really need get_immrbase? I would expect that you can find
> all the registers you need in the device tree, or exported from
> other low-level drivers per subsystem.
> 
> immrbase is a concept from the time before our device trees.
> 
> > +/*
> > + * These are internal use only versions of the structures that
> > + * are exported over PCI by this driver
> > + *
> > + * They are used internally to keep track of the PowerPC queues so that
> > + * we don't have to keep flipping endianness all the time
> > + */
> > +struct vop_loc_desc {
> > +	u32 addr;
        ^^^
Same here.

With kind regards,

Geert Uytterhoeven
Software Architect

Sony Techsoft Centre Europe
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