This patchset introduces a KVM dispatch mechanism which can be used for handling MMIO/PIO accesses over file descriptors without returning from ioctl(KVM_RUN). This allows device emulation to run in another task separate from the vCPU task. This is achieved through KVM vm ioctl for registering MMIO/PIO regions and a wire protocol that KVM uses to communicate with a task handling an MMIO/PIO access. TODOs: * Implement KVM_EXIT_IOREGIONFD_FAILURE * Add non-x86 arch support * Add kvm-unittests Elena Afanasova (4): KVM: add initial support for KVM_SET_IOREGION KVM: x86: add support for ioregionfd signal handling KVM: add support for ioregionfd cmds/replies serialization KVM: enforce NR_IOBUS_DEVS limit if kmemcg is disabled arch/x86/kvm/Kconfig | 1 + arch/x86/kvm/Makefile | 1 + arch/x86/kvm/x86.c | 216 ++++++++++++++- include/kvm/iodev.h | 14 + include/linux/kvm_host.h | 34 +++ include/uapi/linux/ioregion.h | 32 +++ include/uapi/linux/kvm.h | 23 ++ virt/kvm/Kconfig | 3 + virt/kvm/eventfd.c | 25 ++ virt/kvm/eventfd.h | 14 + virt/kvm/ioregion.c | 479 ++++++++++++++++++++++++++++++++++ virt/kvm/ioregion.h | 15 ++ virt/kvm/kvm_main.c | 68 ++++- 13 files changed, 905 insertions(+), 20 deletions(-) create mode 100644 include/uapi/linux/ioregion.h create mode 100644 virt/kvm/eventfd.h create mode 100644 virt/kvm/ioregion.c create mode 100644 virt/kvm/ioregion.h -- 2.25.1
