On 8/4/2016 12:51 PM, Igor Ryzhov wrote:
> Hello Ferruh,
>
>> 4 ???. 2016 ?., ? 14:33, Ferruh Yigit <ferruh.yigit at intel.com> ???????(?):
>>
>> Hi Igor,
>>
>> On 8/3/2016 5:58 PM, Igor Ryzhov wrote:
>>> Hello.
>>>
>>> Function rte_eth_dev_attach can return false positive result.
>>> It happens because rte_eal_pci_probe_one returns zero if no driver is found
>>> for the device:
>>> ret = pci_probe_all_drivers(dev);
>>> if (ret < 0)
>>> goto err_return;
>>> return 0;
>>> (pci_probe_all_drivers returns 1 in that case)
>>>
>>> For example, it can be easily reproduced by trying to attach virtio device,
>>> managed by kernel driver.
>>
>> You are right, and I did able to reproduce this issue with virtio as you
>> suggest.
>>
>> But I wonder why rte_eth_dev_get_port_by_addr() is not catching this.
>> Perhaps a dev->attached check needs to be added into this function.
With a second check, rte_eth_dev_get_port_by_addr() catches it if the
driver is missing.
But for virtio case, problem is not missing driver.
Problem is eth_virtio_dev_init() is returning a positive value on fail.
Call stack is:
rte_eal_pci_probe_one
pci_probe_all_drivers
rte_eal_pci_probe_one_driver
rte_eth_dev_init
eth_virtio_dev_init
So rte_eal_pci_probe_one_driver() also returns positive value, as no
driver found, and rte_eth_dev_get_port_by_addr() returns a valid
port_id, since rte_eth_dev_init() allocated an eth_dev.
Briefly, this can be fixed in virtio pmd, instead of eal pci.
>>
>>>
>>> I think it should be:
>>> ret = pci_probe_all_drivers(dev);
>>> if (ret)
>>> goto err_return;
>>> return 0;
>>
>> Your proposal looks good to me. Will you send a patch?
>
Original code silently ignores the if driver is missing for that dev,
although it is still questionable, I think we can keep this as it is.
> Patch sent.
Sorry for this, but can you please test with following modification in
virtio:
index 07d6449..c74eeee 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1156,7 +1156,7 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev)
if (pci_dev) {
ret = vtpci_init(pci_dev, hw, &dev_flags);
if (ret)
- return ret;
+ return -1;
}
/* Reset the device although not necessary at startup */
>
>>
>>> Best regards,
>>> Igor
>>>
>>
>
