From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yunhong Jiang Subject: [PATCH 0/5] Threaded MSI interrupt for VFIO PCI device Date: Thu, 3 Dec 2015 10:22:47 -0800 Message-ID: <1449166972-8894-1-git-send-email-yunhong.jiang@linux.intel.com> Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: alex.williamson@redhat.com, pbonzini@redhat.com Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org 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(-) -- 1.8.3.1