Re: [dpdk-dev] [PATCH v5 3/3] PCI: don't use vfio ioctl call to access PIO resource

[Maxime Coquelin <maxime.coquelin@redhat.com>]

bus/pci: ...

On 10/22/20 5:51 PM, 谢华伟(此时此刻） wrote:
> From: "huawei.xhw" <huawei.xhw@alibaba-inc.com>
> 
> VFIO should use the same way to map/read/write PORT IO as UIO, for
> virtio PMD.

Please provide more details in the commit message on why the way VFIO
works today is wrong (The cover letter is lost once applied).

> Signed-off-by: huawei.xhw <huawei.xhw@alibaba-inc.com>

Same comment about name format as on previous patches.

> ---
>  drivers/bus/pci/linux/pci.c     | 8 ++++----
>  drivers/bus/pci/linux/pci_uio.c | 4 +++-
>  2 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
> index 0dc99e9..2ed9f2b 100644
> --- a/drivers/bus/pci/linux/pci.c
> +++ b/drivers/bus/pci/linux/pci.c
> @@ -687,7 +687,7 @@ int rte_pci_write_config(const struct rte_pci_device *device,
>  #ifdef VFIO_PRESENT
>  	case RTE_PCI_KDRV_VFIO:
>  		if (pci_vfio_is_enabled())
> -			ret = pci_vfio_ioport_map(dev, bar, p);
> +			ret = pci_uio_ioport_map(dev, bar, p);

Doesn't it create a regression with regards to needed capabilities?
My understanding is that before this patch we don't need to call iopl(),
whereas once applied it is required, correct?

Regards,
Maxime