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 * Flush waiters if ioregion is deleted v3: - add FAST_MMIO bus support - add KVM_IOREGION_DEASSIGN flag - rename kvm_ioregion read/write file descriptors - split ioregionfd signal handling support into two patches - move ioregion_interrupted flag to ioregion_ctx - reorder ioregion_ctx fields - rework complete_ioregion operations - add signal handling support for crossing a page boundary case - change wire protocol license - fix ioregionfd state machine - remove ioregionfd_cmd info and drop appropriate macros - add comment on ioregionfd cmds/replies serialization - drop kvm_io_bus_finish/prepare() Elena Afanasova (5): KVM: add initial support for KVM_SET_IOREGION KVM: x86: add support for ioregionfd signal handling KVM: implement wire protocol KVM: add ioregionfd context KVM: enforce NR_IOBUS_DEVS limit if kmemcg is disabled arch/x86/kvm/Kconfig | 1 + arch/x86/kvm/Makefile | 1 + arch/x86/kvm/vmx/vmx.c | 40 ++- arch/x86/kvm/x86.c | 273 +++++++++++++++++- include/linux/kvm_host.h | 28 ++ include/uapi/linux/ioregion.h | 30 ++ include/uapi/linux/kvm.h | 25 ++ virt/kvm/Kconfig | 3 + virt/kvm/eventfd.c | 25 ++ virt/kvm/eventfd.h | 14 + virt/kvm/ioregion.c | 529 ++++++++++++++++++++++++++++++++++ virt/kvm/ioregion.h | 15 + virt/kvm/kvm_main.c | 36 ++- 13 files changed, 996 insertions(+), 24 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
