Re: [dpdk-dev] [PATCH] vfio: don't needlessly setup devices in secondary process

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 11/21/18 7:41 PM, Darek Stojaczyk wrote:
> Setting up a device that wasn't setup in the primary
> process will possibly break the primary process. That's
> because the IPC message to retrieve the group fd in the
> primary will also *open* that group if it wasn't opened
> before. Even though the secondary process closes that fd
> soon after as a part of its error handling path, the
> primary process leaks it.
> 
> What's worse, opening that fd on the primary will
> increment the process-local counter of opened groups.
> If it was 0 before, then the group will never be added
> to the vfio container, nor dpdk memory will be ever
> mapped.
> 
> This patch moves the proper error checks earlier in the
> code to fuly prevent setting up devices in secondary

s/fuly/fully/

> processes that weren't setup in the primary process.
> 
> Fixes: 2f4adfad0a69 ("vfio: add multiprocess support")
> Cc: anatoly.burakov@intel.com
> 
> Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
> ---
>   drivers/bus/pci/linux/pci_vfio.c | 12 ++++++------
>   1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c
> index ffd26f195..54a4c959e 100644
> --- a/drivers/bus/pci/linux/pci_vfio.c
> +++ b/drivers/bus/pci/linux/pci_vfio.c
> @@ -794,11 +794,6 @@ pci_vfio_map_resource_secondary(struct rte_pci_device *dev)
>   	snprintf(pci_addr, sizeof(pci_addr), PCI_PRI_FMT,
>   			loc->domain, loc->bus, loc->devid, loc->function);
>   
> -	ret = rte_vfio_setup_device(rte_pci_get_sysfs_path(), pci_addr,
> -					&vfio_dev_fd, &device_info);
> -	if (ret)
> -		return ret;
> -
>   	/* if we're in a secondary process, just find our tailq entry */
>   	TAILQ_FOREACH(vfio_res, vfio_res_list, next) {
>   		if (rte_pci_addr_cmp(&vfio_res->pci_addr,
> @@ -810,9 +805,14 @@ pci_vfio_map_resource_secondary(struct rte_pci_device *dev)
>   	if (vfio_res == NULL) {
>   		RTE_LOG(ERR, EAL, "  %s cannot find TAILQ entry for PCI device!\n",
>   				pci_addr);
> -		goto err_vfio_dev_fd;
> +		return -1;
>   	}
>   
> +	ret = rte_vfio_setup_device(rte_pci_get_sysfs_path(), pci_addr,
> +					&vfio_dev_fd, &device_info);
> +	if (ret)
> +		return ret;
> +
>   	/* map BARs */
>   	maps = vfio_res->maps;
>   
> 

Other than commit message typo:
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime