Messages in this thread | | | Subject | Re: [PATCH 0/9] vfio/fsl-mc: VFIO support for FSL-MC devices | From | Diana Craciun OSS <> | Date | Mon, 30 Mar 2020 18:32:05 +0300 |
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Thanks for looking into this.
On 3/27/2020 11:11 PM, Alex Williamson wrote: > On Mon, 23 Mar 2020 19:19:02 +0200 > Diana Craciun <diana.craciun@oss.nxp.com> wrote: > >> DPAA2 (Data Path Acceleration Architecture) consists in >> mechanisms for processing Ethernet packets, queue management, >> accelerators, etc. >> >> The Management Complex (mc) is a hardware entity that manages the DPAA2 >> hardware resources. It provides an object-based abstraction for software >> drivers to use the DPAA2 hardware. The MC mediates operations such as >> create, discover, destroy of DPAA2 objects. >> The MC provides memory-mapped I/O command interfaces (MC portals) which >> DPAA2 software drivers use to operate on DPAA2 objects. >> >> A DPRC is a container object that holds other types of DPAA2 objects. >> Each object in the DPRC is a Linux device and bound to a driver. >> The MC-bus driver is a platform driver (different from PCI or platform >> bus). The DPRC driver does runtime management of a bus instance. It >> performs the initial scan of the DPRC and handles changes in the DPRC >> configuration (adding/removing objects). >> >> All objects inside a container share the same hardware isolation >> context, meaning that only an entire DPRC can be assigned to >> a virtual machine. >> When a container is assigned to a virtual machine, all the objects >> within that container are assigned to that virtual machine. >> The DPRC container assigned to the virtual machine is not allowed >> to change contents (add/remove objects) by the guest. The restriction >> is set by the host and enforced by the mc hardware. >> >> The DPAA2 objects can be directly assigned to the guest. However >> the MC portals (the memory mapped command interface to the MC) need >> to be emulated because there are commands that configure the >> interrupts and the isolation IDs which are virtual in the guest. >> >> Example: >> echo vfio-fsl-mc > /sys/bus/fsl-mc/devices/dprc.2/driver_override >> echo dprc.2 > /sys/bus/fsl-mc/drivers/vfio-fsl-mc/bind >> >> The dprc.2 is bound to the VFIO driver and all the objects within >> dprc.2 are going to be bound to the VFIO driver. > What's the composition of the IOMMU group, does it start with the DPRC > and each of the objects within the container are added to the same > group as they're created?
Yes, the IOMMU group starts with the DPRC and the other objects are then added to that group.
> > For an alternative to the driver_override mechanism used in this series > of passing the override through various scan/create callbacks, you > might consider something like I did for PCI SR-IOV: > > https://lore.kernel.org/lkml/158396395214.5601.11207416598267070486.stgit@gimli.home/ > > ie. using the bus notifier to setup the driver_override before driver > matching is done. Thanks,
Thanks, I like your approach. I will give it a try.
Diana
> > Alex > >> More details about the DPAA2 objects can be found here: >> Documentation/networking/device_drivers/freescale/dpaa2/overview.rst >> >> The patches are dependent on some changes in the mc-bus (bus/fsl-mc) >> driver. The changes were needed in order to re-use code and to export >> some more functions that are needed by the VFIO driver. >> Currenlty the mc-bus patches are under review: >> https://www.spinics.net/lists/kernel/msg3447567.html >> >> Bharat Bhushan (1): >> vfio/fsl-mc: Add VFIO framework skeleton for fsl-mc devices >> >> Diana Craciun (8): >> vfio/fsl-mc: Scan DPRC objects on vfio-fsl-mc driver bind >> vfio/fsl-mc: Implement VFIO_DEVICE_GET_INFO ioctl >> vfio/fsl-mc: Implement VFIO_DEVICE_GET_REGION_INFO ioctl call >> vfio/fsl-mc: Allow userspace to MMAP fsl-mc device MMIO regions >> vfio/fsl-mc: Added lock support in preparation for interrupt handling >> vfio/fsl-mc: Add irq infrastructure for fsl-mc devices >> vfio/fsl-mc: trigger an interrupt via eventfd >> vfio/fsl-mc: Add read/write support for fsl-mc devices >> >> MAINTAINERS | 6 + >> drivers/vfio/Kconfig | 1 + >> drivers/vfio/Makefile | 1 + >> drivers/vfio/fsl-mc/Kconfig | 9 + >> drivers/vfio/fsl-mc/Makefile | 4 + >> drivers/vfio/fsl-mc/vfio_fsl_mc.c | 660 ++++++++++++++++++++++ >> drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c | 221 ++++++++ >> drivers/vfio/fsl-mc/vfio_fsl_mc_private.h | 56 ++ >> include/uapi/linux/vfio.h | 1 + >> 9 files changed, 959 insertions(+) >> create mode 100644 drivers/vfio/fsl-mc/Kconfig >> create mode 100644 drivers/vfio/fsl-mc/Makefile >> create mode 100644 drivers/vfio/fsl-mc/vfio_fsl_mc.c >> create mode 100644 drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c >> create mode 100644 drivers/vfio/fsl-mc/vfio_fsl_mc_private.h >>
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