Re: [Xen-devel] [v3][PATCH 04/16] xen/passthrough: extend hypercall to support rdm reservation policy

["Chen, Tiejun" <tiejun.chen@xxxxxxxxx>]

On 2015/6/17 18:11, Jan Beulich wrote:
> > > > On 11.06.15 at 03:15, <tiejun.chen@xxxxxxxxx> wrote:
> > @@ -899,7 +899,7 @@ int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, 
> > mfn_t mfn,
> >   }
> >
> >   int set_identity_p2m_entry(struct domain *d, unsigned long gfn,
> > -                           p2m_access_t p2ma)
> > +                           p2m_access_t p2ma, u32 flag)
> Please avoid using fixed width types unless really needed. Using
> uint32_t in the public interface is the right thing to do, but in all
> internal parts affected this can simply be (unsigned) int.
Will do.

> > --- a/xen/drivers/passthrough/device_tree.c
> > +++ b/xen/drivers/passthrough/device_tree.c
> > @@ -52,7 +52,8 @@ int iommu_assign_dt_device(struct domain *d, struct 
> > dt_device_node *dev)
> >               goto fail;
> >       }
> >
> > -    rc = hd->platform_ops->assign_device(d, 0, dt_to_dev(dev));
> > +    rc = hd->platform_ops->assign_device(d, 0, dt_to_dev(dev),
> > +                                         XEN_DOMCTL_DEV_NO_RDM);
> >
> >       if ( rc )
> >           goto fail;
> > @@ -148,6 +149,14 @@ int iommu_do_dt_domctl(struct xen_domctl *domctl, struct 
> > domain *d,
> >           if ( domctl->u.assign_device.dev != XEN_DOMCTL_DEV_DT )
> >               break;
> >
> > +        if ( domctl->u.assign_device.flag == XEN_DOMCTL_DEV_NO_RDM )
> > +        {
> > +            printk(XENLOG_G_ERR "XEN_DOMCTL_assign_device: assign \"%s\""
> > +                   " to dom%u failed (%d) since we don't support RDM.\n",
> > +                   dt_node_full_name(dev), d->domain_id, ret);
> > +            break;
> > +        }
> Isn't the condition inverted, i.e. don't you mean != there?
You're right and thanks.

> > @@ -1577,9 +1578,10 @@ int iommu_do_pci_domctl(
> >           seg = machine_sbdf >> 16;
> >           bus = PCI_BUS(machine_sbdf);
> >           devfn = PCI_DEVFN2(machine_sbdf);
> > +        flag = domctl->u.assign_device.flag;
> >
> >           ret = device_assigned(seg, bus, devfn) ?:
> > -              assign_device(d, seg, bus, devfn);
> > +              assign_device(d, seg, bus, devfn, flag);
> I think you should range check the flag passed to make future
> extensions possible (and to avoid ambiguity on what out of
> range values would mean).
Yeah.

Maybe I can set this comment,

    /* Make sure this is always the last. */ 

#define XEN_DOMCTL_DEV_NO_RDM           2 

    uint32_t  flag;   /* flag of assigned device */


and then

        flag = domctl->u.assign_device.flag;
        if ( flag > XEN_DOMCTL_DEV_NO_RDM )
        {
            printk(XENLOG_G_ERR "XEN_DOMCTL_assign_device: "
                   "assign %04x:%02x:%02x.%u to dom%d failed "
                   "with unknown rdm flag %x. (%d)\n",
                   seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
                   d->domain_id, flag, ret);
            ret = -EINVAL;
            break;
        }


Thanks
Tiejun
> Jan
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