Re: [PATCH v4 4/4] virtio: return 1 to tell the upper layer we don't take over this device

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2016-03-01 07:53, Xie, Huawei:
> On 3/1/2016 3:18 PM, Thomas Monjalon wrote:
> > 2016-02-26 09:53, Huawei Xie:
> >> @@ -1037,8 +1039,11 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev)
> >>  
> >>  	pci_dev = eth_dev->pci_dev;
> >>  
> >> -	if (vtpci_init(pci_dev, hw) < 0)
> >> -		return -1;
> >> +	ret = vtpci_init(pci_dev, hw);
> >> +	if (ret) {
> >> +		rte_free(eth_dev->data->mac_addrs);
> > The freeing seems not related to this patch.
> 
> I can send a separate patch, ok within this patchset?

Yes

> > [...]
> >>  	PMD_INIT_LOG(INFO, "trying with legacy virtio pci.");
> >> -	if (legacy_virtio_resource_init(dev, hw) < 0)
> >> +	if (legacy_virtio_resource_init(dev, hw) < 0) {
> >> +		if (dev->kdrv == RTE_KDRV_UNKNOWN) {
> >> +			PMD_INIT_LOG(INFO,
> >> +				"skip kernel managed virtio device.");
> >> +			return 1;
> >> +		}
> >>  		return -1;
> >> +	}
> > You cannot skip a device if it was whitelisted.
> > I think you should check RTE_DEVTYPE_WHITELISTED_PCI and throw an error
> > in this case.
> 
> I feel there is a subtle difference on the understanding of -w args. To
> me, without it, probe all devices; with it, only probe whiltelisted API.
> That is all.

I don't know if it is clearly documented indeed.

> Do you mean that -w implies that devices whitelisted must be probed
> successfully otherwise we throw an error? If i get it right, then what
> about the devices whitelisted but without PMD driver?

Yes we should probably consider the whitelist as a "forced" init.
Later, we could introduce some device flags for probing/discovery:
PROBE_AUTO, PROBE_FORCE, PROBE_IGNORE. It would make white/black list
more precise.

> I will fix, :).
> if (dev->kdrv == RTE_KDRV_UNKNOWN && dev->devargs->type !=
> RTE_DEVTYPE_WHITELISTED_PCI) {
>         ....
>         return 1;
> }

You should also consider the blacklist case: if there is a blacklist,
the not blacklisted devices must be initialised or throw an error.