From: David Marchand <david.marchand@redhat.com>
To: "Zhang, AlvinX" <alvinx.zhang@intel.com>
Cc: dev <dev@dpdk.org>, Beilei Xing <beilei.xing@intel.com>,
Jeff Guo <jia.guo@intel.com>
Subject: Re: [dpdk-dev] [PATCH] bus/pci: fix mmap PCI resource
Date: Fri, 10 Jul 2020 11:54:02 +0200 [thread overview]
Message-ID: <CAJFAV8xNh2XHS1YO4TwAi54_UAVaYj60jwAovnqgaPySS3yKbQ@mail.gmail.com> (raw)
In-Reply-To: <20200708092435.9776-1-alvinx.zhang@intel.com>
On Wed, Jul 8, 2020 at 11:26 AM <alvinx.zhang@intel.com> wrote:
>
> From: Alvin Zhang <alvinx.zhang@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: talshn@mellanox.com
>
> Signed-off-by: Alvin Zhang <alvinx.zhang@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
next prev parent reply other threads:[~2020-07-10 9:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 9:24 alvinx.zhang
2020-07-08 9:38 ` David Marchand
2020-07-08 13:58 ` Xia, Chenbo
2020-07-09 5:13 ` Zhang, AlvinX
2020-07-09 5:21 ` Xia, Chenbo
2020-07-09 2:25 ` Xiao, QimaiX
2020-07-10 9:54 ` David Marchand [this message]
2020-07-10 10:07 ` Thomas Monjalon
2020-07-10 12:31 ` Thomas Monjalon
2020-07-10 12:43 ` [dpdk-dev] [dpdk-ci] " Lincoln Lavoie
2020-09-23 7:34 ` [dpdk-dev] " David Marchand
2020-07-11 6:57 ` Zhang, AlvinX
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