Re: [dpdk-dev] [PATCH] pci: properly parse 32-bit domain numbers

["Gaëtan Rivet" <grive@u256.net>]

On 12/05/20 11:16 -0700, Stephen Hemminger wrote:
> 
> 
> On Tue, May 12, 2020 at 3:30 pm, Darek Stojaczyk
> <dariusz.stojaczyk@intel.com> wrote:
> > The parsing code was bailing on domains greater than UINT16_MAX,
> > but domain numbers like that are still valid and present on some
> > systems.
> > One example is Intel VMD (Volume Management Device), which acts somewhat
> > as a software-managed PCI switch and its upstream linux driver assigns
> > all downstream devices a PCI domain of 0x10000.
> > 
> > Parsing a BDF like 10000:01:00.0 was failing before. To fix it, increase
> > the upper limit of domain number to UINT32_MAX. This matches the size of
> > struct rte_pci_addr->domain (uint32).
> > 
> > Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com
> > <mailto:dariusz.stojaczyk@intel.com>>

The original code predates the change from macro in commit c742e8d3110b.

Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org

Thanks for the fix,
Acked-by: Gaetan Rivet <grive@u256.net>

> > ---
> >  lib/librte_pci/rte_pci.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/lib/librte_pci/rte_pci.c b/lib/librte_pci/rte_pci.c
> > index d1ab6b414d..ad2cdfebb2 100644
> > --- a/lib/librte_pci/rte_pci.c
> > +++ b/lib/librte_pci/rte_pci.c
> > @@ -72,9 +72,9 @@ pci_dbdf_parse(const char *input, struct rte_pci_addr
> > *dev_addr)
> > 
> >  	errno = 0;
> >  	val = strtoul(in, &end, 16);
> > -	if (errno != 0 || end[0] != ':' || val > UINT16_MAX)
> > +	if (errno != 0 || end[0] != ':' || val > UINT32_MAX)
> >  		return -EINVAL;
> > -	dev_addr->domain = (uint16_t)val;
> > +	dev_addr->domain = (uint32_t)val;
> >  	in = end + 1;
> >  	in = get_u8_pciaddr_field(in, &dev_addr->bus, ':');
> >  	if (in == NULL)
> > --
> > 2.17.1
> 
> 
> Agree this came up before on Hyper-V as well. It meant fixing libpci.
> 
> Not sure the cast of val is necessary, other than an attempt to silence some
> static checker
> about implicit type conversion causing loss of precision.
> 
> 
> > 
> 

The cast is useless indeed. Remnants from the original macro.
For now best to leave it as-is, make another patch to remove those
casts.

There are other potential bugs in parsing, -FFFFFFFFFFFF0001 is
considered valid (-FFFFFFFF00000001 with this patch) as well as an empty domain.
I will send a fix for those.

-- 
Gaëtan