10/07/2020 11:54, David Marchand:
> On Wed, Jul 8, 2020 at 11:26 AM <alvinx.zh...@intel.com> wrote:
> > From: Alvin Zhang <alvinx.zh...@intel.com>
> >
> > When mapping a PCI BAR containing an MSI-X table, some devices do not
> > need to actually map this BAR or only need to map part of them, which
> > may cause the mapping to fail. Now some checks are added and a non-NULL
> > initial value is set to the variable to avoid this situation.
Note: this regression would not have happened if we had some CI tests
for simple device probing.
Please let's invest more in CI.
> > Fixes: 2fd3567e5425 ("pci: use OS generic memory mapping functions")
> > Cc: tal...@mellanox.com
No he was not Cc in the thread. Same for Anatoly.
Adding more people in Cc...
> > Signed-off-by: Alvin Zhang <alvinx.zh...@intel.com>
> > ---
> > --- a/drivers/bus/pci/linux/pci_vfio.c
> > +++ b/drivers/bus/pci/linux/pci_vfio.c
> > @@ -547,6 +547,14 @@
> > bar_index,
> > memreg[0].offset, memreg[0].size,
> > memreg[1].offset, memreg[1].size);
> > +
> > + if (memreg[0].size == 0 && memreg[1].size == 0) {
> > + /* No need to map this BAR */
> > + RTE_LOG(DEBUG, EAL, "Skipping BAR%d\n", bar_index);
> > + bar->size = 0;
> > + bar->addr = 0;
> > + return 0;
> > + }
>
> We already have a check on bar size == 0.
> Why would we have this condition?
> Broken hw?
>
>
> > } else {
> > memreg[0].offset = bar->offset;
> > memreg[0].size = bar->size;
> > @@ -556,7 +564,9 @@
> > bar_addr = mmap(bar->addr, bar->size, 0, MAP_PRIVATE |
> > MAP_ANONYMOUS | additional_flags, -1, 0);
> > if (bar_addr != MAP_FAILED) {
> > - void *map_addr = NULL;
> > + /* Set non NULL initial value for in case of no PCI mapping
> > */
> > + void *map_addr = bar_addr;
> > +
>
> It took me some time to understand this code...
> Anyway, we have a regression in the librte_pci.
> This is where the fix should be.
Yes, I am going to send a fix.
> We can cleanup this code later.
Yes please, this function isn't understandable and lack of comments.
Anatoly please?
