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.
>
> Fixes: 2fd3567e5425 ("pci: use OS generic memory mapping functions")
> Cc: tal...@mellanox.com
>
> Signed-off-by: Alvin Zhang <alvinx.zh...@intel.com>
> ---
> drivers/bus/pci/linux/pci_vfio.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/bus/pci/linux/pci_vfio.c
> b/drivers/bus/pci/linux/pci_vfio.c
> index fdeb9a8..9143bfc 100644
> --- 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.
We can cleanup this code later.
> if (memreg[0].size) {
> /* actual map of first part */
> map_addr = pci_map_resource(bar_addr, vfio_dev_fd,
> --
> 1.8.3.1
>
Thanks.
--
David Marchand
