> -----Original Message----- > From: Eric Auger [mailto:eric.auger@xxxxxxxxxx] > Sent: Monday, November 24, 2014 2:36 AM > To: eric.auger@xxxxxx; eric.auger@xxxxxxxxxx; christoffer.dall@xxxxxxxxxx; > marc.zyngier@xxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > kvmarm@xxxxxxxxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; > alex.williamson@xxxxxxxxxx; joel.schopp@xxxxxxx; > kim.phillips@xxxxxxxxxxxxx; paulus@xxxxxxxxx; gleb@xxxxxxxxxx; > pbonzini@xxxxxxxxxx; agraf@xxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx; patches@xxxxxxxxxx; will.deacon@xxxxxxx; > a.motakis@xxxxxxxxxxxxxxxxxxxxxx; a.rigo@xxxxxxxxxxxxxxxxxxxxxx; > john.liuli@xxxxxxxxxx; ming.lei@xxxxxxxxxxxxx; Wu, Feng > Subject: [PATCH v3 0/8] KVM-VFIO IRQ forward control > > This series proposes an integration of "ARM: Forwarding physical > interrupts to a guest VM" (http://lwn.net/Articles/603514/) in > KVM. > > It enables to transform a VFIO platform driver IRQ into a forwarded > IRQ. > > When a physical IRQ is forwarded (to a guest), the host does not > deactivates this latter. Completion ownership is transferred to the > guest. When the guest deactivates the associated virtual IRQ, > the interrupt controler automatically completes the physical IRQ. > Obviously this requires some dedicated HW support in the interrupt > controler. > > The direct benefit is that, for a level sensitive IRQ, it avoids a > VM exit on forwarded IRQ completion. > > When the IRQ is forwarded, the VFIO platform driver does not need to > mask the physical IRQ anymore before signaling the eventfd. Indeed > genirq lowers the running priority, enabling other physical IRQ to hit > except that one. > > Besides, the injection still is based on irqfd triggering. The only > impact on irqfd process is resamplefd is not called anymore on > virtual IRQ completion since this latter becomes "transparent". > > The current integration is based on an extension of the KVM-VFIO > device, previously used by KVM to interact with VFIO groups. The > patch series now enables KVM to directly interact with a VFIO > platform device. The VFIO external API was extended for that purpose. > > Th KVM-VFIO device can get/put the vfio platform device, check its > integrity and type, get the IRQ number associated to an IRQ index. > > The IRQ forward programming is architecture specific (virtual interrupt > controller programming basically). However the whole infrastructure is > kept generic. > > from a user point of view, the functionality is provided through a > new KVM-VFIO group named KVM_DEV_VFIO_DEVICE and 2 associated > attributes: > - KVM_DEV_VFIO_DEVICE_FORWARD_IRQ, > - KVM_DEV_VFIO_DEVICE_UNFORWARD_IRQ. > > The capability can be checked with KVM_HAS_DEVICE_ATTR. > > Forwarding must be activated before VFIO signaling mechanism is set > using VFIO_DEVICE_SET_IRQS and unset while the signaling is disabled. > > --- > > This patch series has the following dependencies: > - "ARM: Forwarding physical interrupts to a guest VM" > (http://lwn.net/Articles/603514/) > - [PATCH v9 00/19] VFIO support for platform and AMBA devices on ARM > (http://www.spinics.net/lists/kvm-arm/msg11745.html) > - [PATCH v2 0/6] vfio: type1: support for ARM SMMUS with > VFIO_IOMMU_TYPE1 > (http://www.spinics.net/lists/kvm-arm/msg11738.html) > > Integrated pieces can be found at > ssh://git.linaro.org/people/eric.auger/linux.git > on branch irqfd_integ_v8 > > This was was tested on Calxeda Midway, assigning the xgmac main IRQ. > Hi Eric, Did you send out the latest QEMU part for this patch set, I notice that v6 of The QEMU part is sent out, but seems some structure in this new version has been changed, such as, struct kvm_arch_forwarded_irq (subindex is added in this version), so a new patchset in QEMU is also needed. Thanks, Feng > v2 -> v3: > - kvm_fwd_irq_action enum replaced by a bool (KVM_VFIO_IRQ_CLEANUP does > not > exist anymore) > - a new struct local to vfio.c was introduced to wrap kvm_fw_irq and make it > linkable: kvm_vfio_fwd_irq_node > - kvm_fwd_irq now is self-contained (includes struct vfio_device *) > - a single list of kvm_vfio_fwd_irq_irq_node is used instead of having > a list of devices and a list of forward irq per device. Having 2 lists > brought extra complexity. > - the VFIO device ref counter is incremented each time a new IRQ is forwarded. > It is not attempted anymore to hold a single reference whatever the number > of forwarded IRQs. > - subindex added on top of index to be closer to VFIO API > - platform device check moved in the arm specific implementation > - enable the KVM-VFIO device for arm64 > - forwarded state change only can happen while the VFIO IRQ handler is not > set; in other words, when the VFIO IRQ signaling is not set. > > v1 -> v2: > - forward control is moved from architecture specific file into generic > vfio.c module. > only kvm_arch_set_fwd_state remains architecture specific > - integrate Kim's patch which enables KVM-VFIO for ARM > - fix vgic state bypass in vgic_queue_hwirq > - struct kvm_arch_forwarded_irq moved from > arch/arm/include/uapi/asm/kvm.h > to include/uapi/linux/kvm.h > also irq_index renamed into index and guest_irq renamed into gsi > - ASSIGN/DEASSIGN renamed into FORWARD/UNFORWARD > - vfio_external_get_base_device renamed into vfio_external_base_device > - vfio_external_get_type removed > - kvm_vfio_external_get_base_device renamed into > kvm_vfio_external_base_device > - __KVM_HAVE_ARCH_KVM_VFIO renamed into > __KVM_HAVE_ARCH_KVM_VFIO_FORWARD > > > Eric Auger (7): > KVM: arm64: Enable the KVM-VFIO device > VFIO: platform: forwarded state tested when selecting IRQ handler > KVM: kvm-vfio: User API for IRQ forwarding > VFIO: External user API device helpers > KVM: kvm-vfio: wrapper to VFIO external API device helpers > KVM: kvm-vfio: generic forwarding control > KVM: arm: kvm-vfio: forwarding control > > Kim Phillips (1): > KVM: arm: Enable the KVM-VFIO device > > Documentation/virtual/kvm/devices/vfio.txt | 34 +++- > arch/arm/include/asm/kvm_host.h | 7 + > arch/arm/kvm/Kconfig | 1 + > arch/arm/kvm/Makefile | 4 +- > arch/arm/kvm/kvm_vfio_arm.c | 101 ++++++++++ > arch/arm64/kvm/Kconfig | 1 + > arch/arm64/kvm/Makefile | 2 +- > drivers/vfio/platform/vfio_platform_irq.c | 7 +- > drivers/vfio/vfio.c | 24 +++ > include/linux/kvm_host.h | 28 +++ > include/linux/vfio.h | 3 + > include/uapi/linux/kvm.h | 10 + > virt/kvm/vfio.c | 294 > ++++++++++++++++++++++++++++- > 13 files changed, 503 insertions(+), 13 deletions(-) > create mode 100644 arch/arm/kvm/kvm_vfio_arm.c > > -- > 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
