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

["Ma, WenwuX" <wenwux.ma@intel.com>]

Hi,

> -----Original Message-----
> From: Gupta, Nipun <nipun.gupta@amd.com>
> Sent: 2023年8月13日 14:15
> To: Ma, WenwuX <wenwux.ma@intel.com>; dev@dpdk.org
> Cc: david.marchand@redhat.com; maxime.coquelin@redhat.com; Xia,
> Chenbo <chenbo.xia@intel.com>; Li, Miao <miao.li@intel.com>; Ling, WeiX
> <weix.ling@intel.com>; stable@dpdk.org
> Subject: Re: [PATCH] bus/pci: fix legacy device IO port map in secondary
> process
> 
> 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@dpdk.org
> >
> > Signed-off-by: Wenwu Ma <wenwux.ma@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"?
> 
1. yes, it is via "virtio_read_caps".

2. if (pdev->region[bar].size == 0 && pdev->region[bar].offset == 0)
    Do you think it's better this way?

> 
> > +		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"?
> 
Yes, we need release group fd, I will add it.

Thanks.

> 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;