As promised, here's a (compile-tested only) patchset that proposes an alternative interrupt injection interface, not using eventfd.
The idea here is that we give user the ability to create "virtual device" file descriptors from kvm context, and bind them to in-kernel drivers. One kind of such device would be virt_irq which let the user inject interrupts. This seems to solve all potential lifetime and locking issues because we control file_operations for both kvm fd and the device(irq) fd. Another kind of device could be kernel-level virtio_net_host implementation (which is really why I started writing this code). As an attempt to make virtual devices more useful, they actually use an abstract virt_hypervisor interface. I have currently only implemented it in kvm, but it will be possible to have lguest implement it as well, and then lguest will be able to use e.g. in-kernel virtio-net. Let's discuss whether we want this, or eventfd, or both. -- MST Michael S. Tsirkin (3): virt-core: binding together drivers and hypervisors kvm: virtual device support virt_irq: virtual device for injecting interrupts arch/x86/kvm/Kconfig | 1 + drivers/Makefile | 1 + drivers/virt/Kconfig | 11 +++++ drivers/virt/Makefile | 2 + drivers/virt/virt_core.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++ drivers/virt/virt_irq.c | 78 ++++++++++++++++++++++++++++++++ include/linux/kvm.h | 13 +++++ include/linux/kvm_host.h | 3 + include/linux/virt.h | 94 +++++++++++++++++++++++++++++++++++++++ include/linux/virt_irq.h | 19 ++++++++ virt/kvm/kvm_main.c | 47 +++++++++++++++++++ 11 files changed, 380 insertions(+), 0 deletions(-) create mode 100644 drivers/virt/Kconfig create mode 100644 drivers/virt/Makefile create mode 100644 drivers/virt/virt_core.c create mode 100644 drivers/virt/virt_irq.c create mode 100644 include/linux/virt.h create mode 100644 include/linux/virt_irq.h -- 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