On Tue, 19 Dec 2023 11:32:38 +0200 Yishai Hadas <yishaih@xxxxxxxxxx> wrote: > This series introduce a vfio driver over virtio devices to support the > legacy interface functionality for VFs. > > Background, from the virtio spec [1]. > -------------------------------------------------------------------- > In some systems, there is a need to support a virtio legacy driver with > a device that does not directly support the legacy interface. In such > scenarios, a group owner device can provide the legacy interface > functionality for the group member devices. The driver of the owner > device can then access the legacy interface of a member device on behalf > of the legacy member device driver. > > For example, with the SR-IOV group type, group members (VFs) can not > present the legacy interface in an I/O BAR in BAR0 as expected by the > legacy pci driver. If the legacy driver is running inside a virtual > machine, the hypervisor executing the virtual machine can present a > virtual device with an I/O BAR in BAR0. The hypervisor intercepts the > legacy driver accesses to this I/O BAR and forwards them to the group > owner device (PF) using group administration commands. > -------------------------------------------------------------------- > > The first 6 patches are in the virtio area and handle the below: > - Introduce the admin virtqueue infrastcture. > - Expose the layout of the commands that should be used for > supporting the legacy access. > - Expose APIs to enable upper layers as of vfio, net, etc > to execute admin commands. > > The above follows the virtio spec that was lastly accepted in that area > [1]. > > The last 3 patches are in the vfio area and handle the below: > - Expose some APIs from vfio/pci to be used by the vfio/virtio driver. > - Introduce a vfio driver over virtio devices to support the legacy > interface functionality for VFs. > > The series was tested successfully over virtio-net VFs in the host, > while running in the guest both modern and legacy drivers. > > [1] > https://github.com/oasis-tcs/virtio-spec/commit/03c2d32e5093ca9f2a17797242fbef88efe94b8c > > Changes from V9: https://lore.kernel.org/kvm/20231218083755.96281-1-yishaih@xxxxxxxxxx/ > Virtio: > - Introduce a new config option VIRTIO_PCI_ADMIN_LEGACY which considers X86 or > COMPILE_TEST, then use it instead of CONFIG_X86. > Vfio: > Patch #9: > - Change Kconfig to depend on VIRTIO_PCI_ADMIN_LEGACY. > - Drop a redundant blank line at the end of Makefile. > > The above changes were suggested by Alex. > > Changes from V8: https://lore.kernel.org/kvm/20231214123808.76664-1-yishaih@xxxxxxxxxx/ > Virtio: > - Adapt to support the legacy IO functionality only on X86, as > was suggested by Michael. > Vfio: > Patch #9: > - Change Kconfig to depend on X86, as suggested by Alex. > - Add Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>. > > Changes from V7: https://lore.kernel.org/kvm/20231207102820.74820-1-yishaih@xxxxxxxxxx/ > Virtio: > Patch #6 > - Let virtio_pci_admin_has_legacy_io() return false on non X86 systems, > as was discussed with Michael. > Vfio: > Patch #7, #8: > - Add Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx> > Patch #9: > - Improve the Kconfig description and the commit log, as was suggested by Kevin. > - Rename translate_io_bar_to_mem_bar() to virtiovf_pci_bar0_rw(), as > was suggested by Kevin. > - Refactor to have virtiovf_pci_write_config() as we have > virtiovf_pci_read_config(), as was suggested by Kevin. > - Drop a note about MSIX which doesn't give any real value, as was > suggested by Kevin. > > Changes from V6: https://lore.kernel.org/kvm/20231206083857.241946-1-yishaih@xxxxxxxxxx/ > Vfio: > - Put the pm_runtime stuff into translate_io_bar_to_mem_bar() and > organize the callers to be more success oriented, as suggested by Jason. > - Add missing 'ops' (i.e. 'detach_ioas' and 'device_feature'), as mentioned by Jason. > - Clean virtiovf_bar0_exists() to cast to bool automatically, as > suggested by Jason. > - Add Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>. > > Changes from V5: https://lore.kernel.org/kvm/20231205170623.197877-1-yishaih@xxxxxxxxxx/ > Vfio: > - Rename vfio_pci_iowrite64 to vfio_pci_core_iowrite64 as was mentioned > by Alex. > > Changes from V4: https://lore.kernel.org/all/20231129143746.6153-7-yishaih@xxxxxxxxxx/T/ > Virtio: > - Drop the unused macro 'VIRTIO_ADMIN_MAX_CMD_OPCODE' as was asked by > Michael. > - Add Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > Vfio: > - Export vfio_pci_core_setup_barmap() in place and rename > vfio_pci_iowrite/read<xxx> to have the 'core' prefix as part of the > functions names, as was discussed with Alex. > - Improve packing of struct virtiovf_pci_core_device, as was suggested > by Alex. > - Upon reset, set 'pci_cmd' back to zero, in addition, if > the user didn't set the 'PCI_COMMAND_IO' bit, return -EIO upon any > read/write towards the IO bar, as was suggested by Alex. > - Enforce by BUILD_BUG_ON that 'bar0_virtual_buf_size' is power of 2 as > part of virtiovf_pci_init_device() and clean the 'sizing calculation' > code accordingly, as was suggested by Alex. > > Changes from V3: https://www.spinics.net/lists/kvm/msg333008.html > Virtio: > - Rebase on top of 6.7 rc3. > Vfio: > - Fix a typo, drop 'acc' from 'virtiovf_acc_vfio_pci_tran_ops'. > > Changes from V2: https://lore.kernel.org/all/20231029155952.67686-8-yishaih@xxxxxxxxxx/T/ > Virtio: > - Rebase on top of 6.7 rc1. > - Add a mutex to serialize admin commands execution and virtqueue > deletion, as was suggested by Michael. > - Remove the 'ref_count' usage which is not needed any more. > - Reduce the depth of the admin vq to match a single command at a given time. > - Add a supported check upon command execution and move to use a single > flow of virtqueue_exec_admin_cmd(). > - Improve the description of the exported commands to better match the > specification and the expected usage as was asked by Michael. > > Vfio: > - Upon calling to virtio_pci_admin_legacy/common_device_io_read/write() > supply the 'offset' within the relevant configuration area, following > the virtio exported APIs. > > Changes from V1: https://lore.kernel.org/all/20231023104548.07b3aa19.alex.williamson@xxxxxxxxxx/T/ > Virtio: > - Drop its first patch, it was accepted upstream already. > - Add a new patch (#6) which initializes the supported admin commands > upon admin queue activation as was suggested by Michael. > - Split the legacy_io_read/write commands per common/device > configuration as was asked by Michael. > - Don't expose any more the list query/used APIs outside of virtio. > - Instead, expose an API to check whether the legacy io functionality is > supported as was suggested by Michael. > - Fix some Krobot's note by adding the missing include file. > > Vfio: > - Refer specifically to virtio-net as part of the driver/module description > as Alex asked. > - Change to check MSIX enablement based on the irq type of the given vfio > core device. In addition, drop its capable checking from the probe flow > as was asked by Alex. > - Adapt to use the new virtio exposed APIs and clean some code accordingly. > - Adapt to some cleaner style code in some places (if/else) as was suggested > by Alex. > - Fix the range_intersect_range() function and adapt its usage as was > pointed by Alex. > - Make struct virtiovf_pci_core_device better packed. > - Overwrite the subsystem vendor ID to be 0x1af4 as was discussed in > the ML. > - Add support for the 'bar sizing negotiation' as was asked by Alex. > - Drop the 'acc' from the 'ops' as Alex asked. > > Changes from V0: https://www.spinics.net/lists/linux-virtualization/msg63802.html > > Virtio: > - Fix the common config map size issue that was reported by Michael > Tsirkin. > - Do not use vp_dev->vqs[] array upon vp_del_vqs() as was asked by > Michael, instead skip the AQ specifically. > - Move admin vq implementation into virtio_pci_modern.c as was asked by > Michael. > - Rename structure virtio_avq to virtio_pci_admin_vq and some extra > corresponding renames. > - Remove exported symbols virtio_pci_vf_get_pf_dev(), > virtio_admin_cmd_exec() as now callers are local to the module. > - Handle inflight commands as part of the device reset flow. > - Introduce APIs per admin command in virtio-pci as was asked by Michael. > > Vfio: > - Change to use EXPORT_SYMBOL_GPL instead of EXPORT_SYMBOL for > vfio_pci_core_setup_barmap() and vfio_pci_iowrite#xxx() as pointed by > Alex. > - Drop the intermediate patch which prepares the commands and calls the > generic virtio admin command API (i.e. virtio_admin_cmd_exec()). > - Instead, call directly to the new APIs per admin command that are > exported from Virtio - based on Michael's request. > - Enable only virtio-net as part of the pci_device_id table to enforce > upon binding only what is supported as suggested by Alex. > - Add support for byte-wise access (read/write) over the device config > region as was asked by Alex. > - Consider whether MSIX is practically enabled/disabled to choose the > right opcode upon issuing read/write admin command, as mentioned > by Michael. > - Move to use VIRTIO_PCI_CONFIG_OFF instead of adding some new defines > as was suggested by Michael. > - Set the '.close_device' op to vfio_pci_core_close_device() as was > pointed by Alex. > - Adapt to Vfio multi-line comment style in a few places. > - Add virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx in the MAINTAINERS file > to be CCed for the new driver as was suggested by Jason. > > Yishai > > Feng Liu (4): > virtio: Define feature bit for administration virtqueue > virtio-pci: Introduce admin virtqueue > virtio-pci: Introduce admin command sending function > virtio-pci: Introduce admin commands > > Yishai Hadas (5): > virtio-pci: Initialize the supported admin commands > virtio-pci: Introduce APIs to execute legacy IO admin commands > vfio/pci: Expose vfio_pci_core_setup_barmap() > vfio/pci: Expose vfio_pci_core_iowrite/read##size() > vfio/virtio: Introduce a vfio driver over virtio devices > > MAINTAINERS | 7 + > drivers/vfio/pci/Kconfig | 2 + > drivers/vfio/pci/Makefile | 2 + > drivers/vfio/pci/vfio_pci_rdwr.c | 57 +- > drivers/vfio/pci/virtio/Kconfig | 15 + > drivers/vfio/pci/virtio/Makefile | 3 + > drivers/vfio/pci/virtio/main.c | 576 ++++++++++++++++++++ > drivers/virtio/Kconfig | 5 + > drivers/virtio/Makefile | 1 + > drivers/virtio/virtio.c | 37 +- > drivers/virtio/virtio_pci_admin_legacy_io.c | 244 +++++++++ > drivers/virtio/virtio_pci_common.c | 14 + > drivers/virtio/virtio_pci_common.h | 42 +- > drivers/virtio/virtio_pci_modern.c | 259 ++++++++- > drivers/virtio/virtio_pci_modern_dev.c | 24 +- > include/linux/vfio_pci_core.h | 20 + > include/linux/virtio.h | 8 + > include/linux/virtio_config.h | 4 + > include/linux/virtio_pci_admin.h | 23 + > include/linux/virtio_pci_modern.h | 2 + > include/uapi/linux/virtio_config.h | 8 +- > include/uapi/linux/virtio_pci.h | 68 +++ > 22 files changed, 1385 insertions(+), 36 deletions(-) > create mode 100644 drivers/vfio/pci/virtio/Kconfig > create mode 100644 drivers/vfio/pci/virtio/Makefile > create mode 100644 drivers/vfio/pci/virtio/main.c > create mode 100644 drivers/virtio/virtio_pci_admin_legacy_io.c > create mode 100644 include/linux/virtio_pci_admin.h > The vfio parts look good to me. I'll merge the last 3 patches in the series through the vfio tree once virtio maintainers are satisfied and provide a branch or tag to merge the dependencies. Thanks, Alex
