This series of patches provides a way to implement IRQFD support without having to implement IRQ routing, and adds IRQFD support for the XICS interrupt controller emulation. (XICS is the interrupt controller defined for the pSeries machine type, used on IBM POWER servers). The basic approach is to make it easy for code other than irqchip.c to provide a mapping from a global interrupt number (GSI) to an irq routing entry (struct kvm_kernel_irq_routing_entry). To make the lifetime of this routing entry easier to manage, we change the IRQFD code to keep a copy of the routing entry (for the MSI fast-path case) rather than a pointer to the routing entry. Since the copy can't be updated atomically, we add a seqcount_t to make sure that when reading it we get a copy that hasn't been half-way updated. Next we replace the hard-coded accesses outside irqchip.c to the fields of the kvm_irq_routing_table struct with calls to accessor functions in irqchip.c, namely kvm_irq_map_gsi() and kvm_irq_map_chip_pin(). That enables us to move all references to the kvm_irq_routing_table struct, and the definition of that struct, into irqchip.c. Then we move the irq notifier implementation from irqchip.c into eventfd.c and add a separate Kconfig option to enable IRQFD. With that we can enable IRQFD without irq routing, which we achieve by compiling in eventfd.c but not irqchip.c, and providing an alternative implementation of kvm_irq_map_gsi() and kvm_irq_map_chip_pin(). The last patch does that for XICS. With this series I can use vhost-net with KVM guests, and I see the TCP bandwidth between guest and host on a POWER8 machine go from around 700MB/s to over 2GB/s. I would like to see this go into 3.17. arch/ia64/kvm/Kconfig | 1 + arch/powerpc/kvm/Kconfig | 3 + arch/powerpc/kvm/book3s_hv_rm_xics.c | 5 ++ arch/powerpc/kvm/book3s_xics.c | 55 +++++++++++--- arch/powerpc/kvm/book3s_xics.h | 2 + arch/powerpc/kvm/mpic.c | 4 +- arch/s390/kvm/Kconfig | 1 + arch/s390/kvm/interrupt.c | 3 +- arch/x86/kvm/Kconfig | 1 + include/linux/kvm_host.h | 43 ++++------- virt/kvm/Kconfig | 3 + virt/kvm/eventfd.c | 134 ++++++++++++++++++++++++++--------- virt/kvm/irq_comm.c | 24 +++---- virt/kvm/irqchip.c | 98 ++++++++++--------------- virt/kvm/kvm_main.c | 2 +- 15 files changed, 227 insertions(+), 152 deletions(-) -- 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
