[dpdk-dev] [PATCH] bus/pci: fix Windows kernel driver categories

[Ranjit Menon]

On 3/18/2021 12:49 AM, Thomas Monjalon wrote:
> 18/03/2021 00:17, Ranjit Menon:
>> Hi Thomas,
>>
>> On 3/16/2021 4:11 PM, Thomas Monjalon wrote:
>>> In Windows probing, the value RTE_PCI_KDRV_NONE was used
>>> instead of RTE_PCI_KDRV_UNKNOWN (mlx case),
>>> and RTE_PCI_KDRV_NIC_UIO (FreeBSD) was re-used
>>> instead of having a new RTE_PCI_KDRV_NET_UIO for Windows NetUIO.
>> Shouldn't the mlx case actually remain RTE_PCI_KDRV_NONE?
>>
>> mlx does not require a UIO-like kernel driver...No? And NONE implies that no kernel driver is used/required.
>> Not sure what is correct here.
> No this is a bifurcated model, meaning kernel and userland
> work together. The PCI device is bound to the kernel driver,
> but the driver is not listed because no special treatment is required.
>
>>> While adding the new value RTE_PCI_KDRV_NET_UIO,
>>> the enum of kernel driver categories is annotated.
>>>
>>> Fixes: b762221ac24f ("bus/pci: support Windows with bifurcated drivers")
>>> Fixes: c76ec01b4591 ("bus/pci: support netuio on Windows")
>>> Cc: stable at dpdk.org
>>>
>>> Signed-off-by: Thomas Monjalon <thomas at monjalon.net>
>>> ---
>>>    drivers/bus/pci/rte_bus_pci.h | 13 +++++++------
>>>    drivers/bus/pci/windows/pci.c | 14 +++++++-------
>>>    2 files changed, 14 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/drivers/bus/pci/rte_bus_pci.h b/drivers/bus/pci/rte_bus_pci.h
>>> index fdda046515..3d009cc74b 100644
>>> --- a/drivers/bus/pci/rte_bus_pci.h
>>> +++ b/drivers/bus/pci/rte_bus_pci.h
>>> @@ -52,12 +52,13 @@ TAILQ_HEAD(rte_pci_driver_list, rte_pci_driver);
>>>    struct rte_devargs;
>>>    
>>>    enum rte_pci_kernel_driver {
>>> -	RTE_PCI_KDRV_UNKNOWN = 0,
>>> -	RTE_PCI_KDRV_IGB_UIO,
>>> -	RTE_PCI_KDRV_VFIO,
>>> -	RTE_PCI_KDRV_UIO_GENERIC,
>>> -	RTE_PCI_KDRV_NIC_UIO,
>>> -	RTE_PCI_KDRV_NONE,
>>> +	RTE_PCI_KDRV_UNKNOWN = 0,  /* not listed - may be a bifurcated driver */
>>> +	RTE_PCI_KDRV_IGB_UIO,      /* igb_uio for Linux */
>>> +	RTE_PCI_KDRV_VFIO,         /* VFIO for Linux */
>>> +	RTE_PCI_KDRV_UIO_GENERIC,  /* uio_generic for Linux */
>>> +	RTE_PCI_KDRV_NIC_UIO,      /* nic_uio for FreeBSD */
>>> +	RTE_PCI_KDRV_NONE,         /* error */
>>> +	RTE_PCI_KDRV_NET_UIO,      /* NetUIO for Windows */
>>>    };
>>>    
>> Any chance we can re-order the enums, so that _NONE and _UNKNOWN are at
>> the top?
> No, it would break the ABI.
>
>> This will change the value, and break code where this value was
>> hard-coded. But how likely is that...?
> The problem is when loading the new PCI bus driver with an old device driver.
>
>
>
OK. Thanks for the explanation, Thomas.

ranjit m.