[dpdk-dev] [PATCH v13 02/19] bus/pci: fix PCI address compare

[Zhang, Qi Z]

> -----Original Message-----
> From: Gaëtan Rivet [mailto:gaetan.rivet at 6wind.com]
> Sent: Thursday, July 12, 2018 5:32 PM
> To: Burakov, Anatoly <anatoly.burakov at intel.com>
> Cc: Zhang, Qi Z <qi.z.zhang at intel.com>; thomas at monjalon.net; Ananyev,
> Konstantin <konstantin.ananyev at intel.com>; dev at dpdk.org; Richardson,
> Bruce <bruce.richardson at intel.com>; Yigit, Ferruh <ferruh.yigit at intel.com>;
> Shelton, Benjamin H <benjamin.h.shelton at intel.com>; Vangati, Narender
> <narender.vangati at intel.com>; stable at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v13 02/19] bus/pci: fix PCI address compare
> 
> Hi,
> 
> On Thu, Jul 12, 2018 at 10:24:44AM +0100, Burakov, Anatoly wrote:
> > On 12-Jul-18 2:14 AM, Qi Zhang wrote:
> > > When use memcmp to compare two PCI address, sizeof(struct
> > > rte_pci_addr) is 4 bytes aligned, and it is 8. While only 7 byte of
> > > struct rte_pci_addr is valid. So compare the 8th byte will cause the
> > > unexpected result, which happens when repeatedly attach/detach a
> device.
> > >
> > > Fixes: c752998b5e2e ("pci: introduce library and driver")
> 
> Shouldn't be the original commit be
> 
> Fixes: 94c0776b1bad ("vfio: support hotplug")
> 
> instead?

You are right, this should be one that introduce the issue, thanks!

> 
> > > Cc: stable at dpdk.org
> > >
> > > Signed-off-by: Qi Zhang <qi.z.zhang at intel.com>
> > > ---
> > >   drivers/bus/pci/linux/pci_vfio.c | 13 ++++++++++++-
> > >   1 file changed, 12 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/bus/pci/linux/pci_vfio.c
> > > b/drivers/bus/pci/linux/pci_vfio.c
> > > index aeeaa9ed8..dd25c3542 100644
> > > --- a/drivers/bus/pci/linux/pci_vfio.c
> > > +++ b/drivers/bus/pci/linux/pci_vfio.c
> > > @@ -43,6 +43,17 @@ static struct rte_tailq_elem rte_vfio_tailq = {
> > >   };
> > >   EAL_REGISTER_TAILQ(rte_vfio_tailq)
> > > +/* Compair two pci address */
> > > +static int pci_addr_cmp(struct rte_pci_addr *addr1, struct
> > > +rte_pci_addr *addr2) {
> > > +	if (addr1->domain == addr2->domain &&
> > > +		addr1->bus == addr2->bus &&
> > > +		addr1->devid == addr2->devid &&
> > > +		addr1->function == addr2->function)
> > > +		return 0;
> > > +	return 1;
> > > +}
> >
> > Generally, change looks OK to me, but I think we already have this
> > function in PCI library - rte_pci_addr_cmp(). Is there a specific
> > reason to reimplement it here?
> >
> 
> +1
> 
> > > +
> > >   int
> > >   pci_vfio_read_config(const struct rte_intr_handle *intr_handle,
> > >   		    void *buf, size_t len, off_t offs) @@ -642,7 +653,7 @@
> > > pci_vfio_unmap_resource(struct rte_pci_device *dev)
> > >   	vfio_res_list = RTE_TAILQ_CAST(rte_vfio_tailq.head,
> mapped_pci_res_list);
> > >   	/* Get vfio_res */
> > >   	TAILQ_FOREACH(vfio_res, vfio_res_list, next) {
> > > -		if (memcmp(&vfio_res->pci_addr, &dev->addr, sizeof(dev->addr)))
> > > +		if (pci_addr_cmp(&vfio_res->pci_addr, &dev->addr))
> > >   			continue;
> > >   		break;
> > >   	}
> > >
> >
> >
> > --
> > Thanks,
> > Anatoly
> 
> --
> Gaëtan Rivet
> 6WIND