Alex, can you take a look at the extension to the irq bypass interface in patch 2? I'm not sure I understand what is the case where you have multiple consumers for the same token.
Paolo On 03/12/2015 19:22, Yunhong Jiang wrote: > When assigning a VFIO device to a KVM guest with low latency requirement, it > is better to handle the interrupt in the hard interrupt context, to reduce > the context switch to/from the IRQ thread. > > Based on discussion on https://lkml.org/lkml/2015/10/26/764, the VFIO msi > interrupt is changed to use request_threaded_irq(). The primary interrupt > handler tries to set the guest interrupt atomically. If it fails to achieve > it, a threaded interrupt handler will be invoked. > > The irq_bypass manager is extended for this purpose. The KVM eventfd will > provide a irqbypass consumer to handle the interrupt at hard interrupt > context. The producer will invoke the consumer's handler then. > > Yunhong Jiang (5): > Extract the irqfd_wakeup_pollin/irqfd_wakeup_pollup > Support runtime irq_bypass consumer > Support threaded interrupt handling on VFIO > Add the irq handling consumer > Expose x86 kvm_arch_set_irq_inatomic() > > arch/x86/kvm/Kconfig | 1 + > drivers/vfio/pci/vfio_pci_intrs.c | 39 ++++++++++-- > include/linux/irqbypass.h | 8 +++ > include/linux/kvm_host.h | 19 +++++- > include/linux/kvm_irqfd.h | 1 + > virt/kvm/Kconfig | 3 + > virt/kvm/eventfd.c | 131 > ++++++++++++++++++++++++++------------ > virt/lib/irqbypass.c | 82 ++++++++++++++++++------ > 8 files changed, 214 insertions(+), 70 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html