On Thu, Jun 18, 2015 at 10:14:40AM +0200, Gerd Hoffmann wrote:
> Hi,
>
> > > +static struct resource *request_capability(struct pci_dev *dev, int off,
> > > + const char *name)
> > > +{
> > > + u8 bar;
> > > + u32 offset, length;
> > > +
> > > + pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
> > > + bar),
> > > + &bar);
> > > + pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap,
> > > offset),
> > > + &offset);
> > > + pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap,
> > > length),
> > > + &length);
> > > +
> > > + return request_mem_region(pci_resource_start(dev, bar) + offset,
> > > + length, name);
> > > +}
> > > +
> >
> > For device config, this might request too much. The spec says:
> > The drivers SHOULD only map part of configuration structure large enough
> > for device operation.
>
> We don't map it here though. We just reserve what belongs to virtio
> according to the capabilities.
>
> > I think you should limit this to PAGE_SIZE like we do for map_capability.
>
> notify is much larger than PAGE_SIZE.
Yes - I mean for the device config.
> > > err = -EINVAL;
> > > vp_dev->common = map_capability(pci_dev, common,
> > > sizeof(struct virtio_pci_common_cfg), 4,
> >
> > map_capability has a bunch of checks in place to validate the capability
> > structure. With request_capability called earlier, they are now done too
> > late.
>
> Hmm, lets move the checks to find_capability then?
>
> cheers,
> Gerd
>
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