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: - Fix common config map for modern device as was reported by Michael Tsirkin. - 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 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 (5): virtio-pci: Fix common config map for modern device 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 (4): virtio-pci: Introduce APIs to execute legacy IO admin commands vfio/pci: Expose vfio_pci_core_setup_barmap() vfio/pci: Expose vfio_pci_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_core.c | 25 ++ drivers/vfio/pci/vfio_pci_rdwr.c | 38 +- drivers/vfio/pci/virtio/Kconfig | 15 + drivers/vfio/pci/virtio/Makefile | 4 + drivers/vfio/pci/virtio/main.c | 577 +++++++++++++++++++++++++ drivers/virtio/virtio.c | 37 +- drivers/virtio/virtio_pci_common.c | 14 + drivers/virtio/virtio_pci_common.h | 20 +- drivers/virtio/virtio_pci_modern.c | 441 ++++++++++++++++++- 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 | 18 + include/linux/virtio_pci_modern.h | 5 + include/uapi/linux/virtio_config.h | 8 +- include/uapi/linux/virtio_pci.h | 66 +++ 20 files changed, 1295 insertions(+), 40 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 include/linux/virtio_pci_admin.h -- 2.27.0
