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

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

On 2015/6/17 18:11, Jan Beulich wrote:
>>>> On 11.06.15 at 03:15, <tiejun.chen@intel.com> 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
>
>
>