[PATCH] bus/pci: fix legacy device IO port map in secondary process

[Gupta, Nipun]

Hi Wenwu,

On 8/7/2023 7:28 AM, Wenwu Ma wrote:
> When doing IO port mapping for legacy device
> in secondary process, the region information
> is missing, so, we need to refill it.
> 
> Fixes: 4b741542ecde ("bus/pci: avoid depending on private kernel value")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Wenwu Ma <wenwux.ma at intel.com>
> ---
>   drivers/bus/pci/linux/pci_vfio.c | 21 +++++++++++++++++++++
>   1 file changed, 21 insertions(+)
> 
> diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c
> index e634de8322..eea1c9851e 100644
> --- a/drivers/bus/pci/linux/pci_vfio.c
> +++ b/drivers/bus/pci/linux/pci_vfio.c
> @@ -1306,6 +1306,11 @@ int
>   pci_vfio_ioport_map(struct rte_pci_device *dev, int bar,
>   		    struct rte_pci_ioport *p)
>   {
> +	struct vfio_device_info device_info = { .argsz = sizeof(device_info) };
> +	char pci_addr[PATH_MAX] = {0};
> +	int vfio_dev_fd;
> +	struct rte_pci_addr *loc = &dev->addr;
> +	int ret;
>   	uint64_t size, offset;
>   
>   	if (bar < VFIO_PCI_BAR0_REGION_INDEX ||
> @@ -1314,6 +1319,22 @@ pci_vfio_ioport_map(struct rte_pci_device *dev, int bar,
>   		return -1;
>   	}
>   
> +	if (rte_eal_process_type() == RTE_PROC_SECONDARY) {
> +		/* store PCI address string */
> +		snprintf(pci_addr, sizeof(pci_addr), PCI_PRI_FMT,
> +				loc->domain, loc->bus, loc->devid, loc->function);
> +
> +		ret = rte_vfio_setup_device(rte_pci_get_sysfs_path(), pci_addr,
> +						&vfio_dev_fd, &device_info);

This looks better than fixing in "virtio_remap_pci".

Ideally, these API should be called irrespective of PRIMARY or SECONDARY 
process here. Miao Li mentioned earlier that "rte_pci_map_device" is 
called from primary process, is it via "virtio_read_caps" API? Isn't 
there any other way to detect if it is a virtio legacy device without 
calling "rte_pci_map_device"?


> +		if (ret)
> +			return -1;
> +
> +		ret = pci_vfio_fill_regions(dev, vfio_dev_fd, &device_info);
> +		if (ret)
> +			return -1;

Corresponding cleanup required in "pci_vfio_ioport_unmap"?

Thanks,
Nipun

> +
> +	}
> +
>   	if (pci_vfio_get_region(dev, bar, &size, &offset) != 0) {
>   		RTE_LOG(ERR, EAL, "Cannot get offset of region %d.\n", bar);
>   		return -1;