> -----Original Message----- > From: Eric Auger [mailto:eric.auger@xxxxxxxxxx] > Sent: Monday, November 24, 2014 4:27 PM > To: Wu, Feng; eric.auger@xxxxxx; 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 > Subject: Re: [PATCH v3 0/8] KVM-VFIO IRQ forward control > > On 11/24/2014 09:14 AM, Wu, Feng wrote: > > > > > >> -----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. > > Hi Feng, > > v7 is available at: > http://lists.gnu.org/archive/html/qemu-devel/2014-10/msg03804.html. It > already illustrates KVM-VFIO device usage. > > v8 which will indeed integrate subindex addition will be delivered this > week. > > Best Regards > > Eric Thanks a lot for the information, Eric! Thanks, Feng > > > > 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
