This RFC series aims at enabling KVM platform device passthrough. It implements a VFIO platform device and offers the capability to instantiate this VFIO device in mach-virt. The VFIO platform device uses an host VFIO platform driver which must be bound to the assigned device prior to the QEMU system start. - the guest can directly access the device register space - assigned device IRQs are transparently routed to the guest by QEMU/KVM (2 methods currently are supported) - iommu is transparently programmed to prevent the device from accessing physical pages outside of the guest address space The patch series is made of the following patch files 1) provides a mach_virt implementation where a VFIO device is instantiated at a fixed location 2) addresses A.Williamson's comment to have the platform device code separated from the PCI device code. The VFIO device is moved in a new directory hw/vfio/ 3) provides a VFIO platform device that supports MMIO direct accesses. the vfio device was reworked to factorize at best the code between the PCI device and the platform device. 4) simplifies pci device trace calls using common "name" field 5) provides initial IRQ support. The device IRQ now are routed to the guest. IRQ handling is based on eventfds handled on user side. End of interrupt is detected by trapping guest access to MMIO. Functional but suffers from some performance limitations. 6) enables the QEMU end-user to dynamically assign the device from command line, using -device option. Request a minimal knowledge from the end-user (vfio driver name and compatibility). From that point on the VFIO platform device becomes fully generic. a single compat string is supported. A single MMIO region is supported. 7) regions are IOMMU mapped as executable. This feature is requested for some DMA devices that fetch code from some regions (typically the PL330). 8) Add support for multi compat strings. This feature is requested for Primecell devices 9) forces eventfd notifying mechanism 10) Introduces a new way of IRQ routing (based on KVM irqfd/GSI routing). This method is far more performant than the one introduced in 4) since eventfds are handled on host kernel side and also interrupt completion is trapped at GIC level. v1 (Kim Phillips): Initial versions for 1, 2, 3 v1->v2 changes (Kim Phillips, Eric Auger): - reworked split between PCI and platform (3) - IRQ initial support (5) - dynamic instantiation (6) v2->v3 changes (Alvise Rigo, Eric Auger): - Following Alex recommandations, further efforts to factorize the code between PCI, platform usage of VFIOPlatform and VFIORegion as base classes (3, 4) - cleanup following Kim's comments - multiple IRQ support mechanics should be in place although not tested - Better handling of MMIO multiple regions - New features and fixes by Alvise (7, 8, 9) - irqfd support (10) This patch has the following dependencies on kernel side: - [RFC Patch v5 0/11] VFIO support for platform devices http://www.spinics.net/lists/kvm/msg102309.html - [Patch] ARM: KVM: Handle IPA unmapping on memory region deletion https://patches.linaro.org/27691/ - [PATCH v2] ARM: KVM: add irqfd and irq routing support https://patches.linaro.org/29896/ - [PATCH] ARM: KVM: Enable the KVM-VFIO device https://lists.cs.columbia.edu/pipermail/kvmarm/2014-March/008629.html - [PATCH] ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping https://lists.cs.columbia.edu/pipermail/kvmarm/2014-March/008630.html The patch series was tested on Calxeda Midway (ARMv7) where one xgmac is assigned to KVM host while the second one is assigned to the guest. Tentative Plan: - further IRQ handling optimizations (removal of maintenance IRQ) - unbind/migration/reset problematics - multi-instantiation testing - multiple IRQ testing - management of platform devices with more complex device tree node Here are the instructions to test on a Calxeda Midway: https://wiki.linaro.org/LEG/Engineering/Virtualization/Platform_Device_Passthrough_on_Midway git://git.linaro.org/people/eric.auger/linux.git (branch irqfd_integ_v2) git://git.linaro.org/people/eric.auger/qemu.git (branch vfio-dev-integ-RFCv3) Best Regards Eric Alvise Rigo (3): Add EXEC_FLAG to VFIO DMA mappings Add AMBA devices support to VFIO Always use eventfd as notifying mechanism Eric Auger (4): vfio: simplifed DPRINTF calls using device name vfio: Add initial IRQ support in platform device virt: Assign a VFIO platform device with -device option vfio: Add irqfd support in platform device Kim Phillips (3): hw/arm/virt: add a xgmac device vfio: move hw/misc/vfio.c to hw/vfio/pci.c vfio: add vfio-platform support LICENSE | 2 +- MAINTAINERS | 2 +- hw/Makefile.objs | 1 + hw/arm/virt.c | 238 +++++- hw/intc/arm_gic_kvm.c | 1 + hw/misc/Makefile.objs | 1 - hw/vfio/Makefile.objs | 5 + hw/vfio/common.c | 854 ++++++++++++++++++++++ hw/{misc/vfio.c => vfio/pci.c} | 1562 ++++++++++------------------------------ hw/vfio/platform.c | 733 +++++++++++++++++++ hw/vfio/vfio-common.h | 153 ++++ linux-headers/linux/vfio.h | 3 + 12 files changed, 2378 insertions(+), 1177 deletions(-) create mode 100644 hw/vfio/Makefile.objs create mode 100644 hw/vfio/common.c rename hw/{misc/vfio.c => vfio/pci.c} (65%) create mode 100644 hw/vfio/platform.c create mode 100644 hw/vfio/vfio-common.h -- 1.8.3.2 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
