Re: [dpdk-dev] [PATCH v3 0/3] enable uio_pci_generic support

[Declan Doherty <declan.doherty@intel.com>]

On 20/02/15 16:59, Bruce Richardson wrote:
> v3 changes
> - made processing of uio devices identical, irrespective of igb_uio or uio_pci_generic
> - removed storage of kernel driver name from dev node as now unneeded.
>
> v2 changes:
> - Change variable name of kernel driver with precise comment
> - Fix a union definition error in v1 patchset
> - Move redefined macro IORESOURCE_MEM to rte_pci.h with comment
>
> Linux kernel provides UIO as well as VFIO mechanism to support writing user
> space device driver. Comparing to UIO which is available since 2.6.32 kernel,
> the VFIO is introduced into kernel since version 3.6.0 with better interrupt
> and memory protection (build on top of Intel VT-d technology) supports.
> Basically, UIO and VFIO do two common things below:
> 1) Map PCIe device's I/O memory space to user space driver
> 2) Support device interrupt notification mechanism that notifies user space
>     driver/application when a device interrupt triggers.
>
> To run an DPDK application and make use of VFIO, two in_kernel modules
> vfio and vfio-pci module must be loaded. To use UIO, a DPDK kernel
> module igb_uio, which was there since DPDK is invented, must be loaded to
> attach to in_kernel uio module. As an solution to deprecate igb_uio,
> this patch serials leverage the uio_pci_generic in_kernel module to support
> DPDK user space PMD in a generic fashion (similar to how VFIO works), to
> remove user space DPDK dependency on GPL code igb_uio in kernel.
>
> Example to bind Network Ports to uio_pci_generic:
>             modprobe uio
>             modprobe uio_pci_generic
>             /* to bind device 08:00.0, to the uio_pci_generic driver */
>             ./tools/dpdk_nic_bind.py -b uio_pci_generic 08:00.0
>
> Note: this patch set does not remove igb_uio support due to igb_uio supports
> creating maximum number of SR-IOV VFs (Virtual Functions) by using max_vfs
> kernel parameter on older kernels (kernel 3.7.x and below).
> Specifically, igb_uio explicitly calls pci_enable_sriov() to create VFs, while
> it is not invoked in either uio or uio_pci_generic kernel modules. On kernel 3.8.x
> and above, user can use the standard sysfs to enable VFs. For examples:
>
> #echo $num_vf_enabled > /sys/class/net/$dev/device/sriov_numvfs  // enable VFs
> #echo 0 > /sys/class/net/$dev/device/sriov_numvfs                // disable VFs
>
>
> Zhou Danny (3):
>    eal: enable uio_pci_generic support
>    eal: add interrupt enable/disable routines for uio_pci_generic
>    tools: enable binding NIC device to uio_pci_generic
>
>   lib/librte_eal/common/include/rte_pci.h            |   3 +
>   lib/librte_eal/linuxapp/eal/eal_interrupts.c       |  68 +++++++--
>   lib/librte_eal/linuxapp/eal/eal_pci.c              |   4 +-
>   lib/librte_eal/linuxapp/eal/eal_pci_uio.c          | 167 ++++++++++-----------
>   .../linuxapp/eal/include/exec-env/rte_interrupts.h |   8 +-
>   tools/dpdk_nic_bind.py                             |   2 +-
>   6 files changed, 144 insertions(+), 108 deletions(-)
>


Series Acked-by: Declan Doherty <declan.doherty@intel.com>