To get the ball rolling after my presentation of the topic at KVM Forum [1] and many fruitful discussions around it, this is a first concrete code series. As discussed, I'm starting with the IVSHMEM implementation of a QEMU device and server. It's RFC because, besides specification and implementation details, there will still be some decisions needed about how to integrate the new version best into the existing code bases.
If you want to play with this, the basic setup of the shared memory device is described in patch 1 and 3. UIO driver and also the virtio-ivshmem prototype can be found at http://git.kiszka.org/?p=linux.git;a=shortlog;h=refs/heads/queues/ivshmem2 Accessing the device via UIO is trivial enough. If you want to use it for virtio, this is additionally to the description in patch 3 needed on the virtio console backend side: modprobe uio_ivshmem echo "1af4 1110 1af4 1100 ffc003 ffffff" > /sys/bus/pci/drivers/uio_ivshmem/new_id linux/tools/virtio/virtio-ivshmem-console /dev/uio0 And for virtio block: echo "1af4 1110 1af4 1100 ffc002 ffffff" > /sys/bus/pci/drivers/uio_ivshmem/new_id linux/tools/virtio/virtio-ivshmem-console /dev/uio0 /path/to/disk.img After that, you can start the QEMU frontend instance with the virtio-ivshmem driver installed which can use the new /dev/hvc* or /dev/vda* as usual. Any feedback welcome! Jan PS: Let me know if I missed someone potentially interested in this topic on CC - or if you would like to be dropped from the list. PPS: The Jailhouse queues are currently out of sync /wrt minor details of this one, primarily the device ID. Will update them when the general direction is clear. [1] https://kvmforum2019.sched.com/event/TmxI Jan Kiszka (3): hw/misc: Add implementation of ivshmem revision 2 device docs/specs: Add specification of ivshmem device revision 2 contrib: Add server for ivshmem revision 2 Makefile | 3 + Makefile.objs | 1 + configure | 1 + contrib/ivshmem2-server/Makefile.objs | 1 + contrib/ivshmem2-server/ivshmem2-server.c | 462 ++++++++++++ contrib/ivshmem2-server/ivshmem2-server.h | 158 +++++ contrib/ivshmem2-server/main.c | 313 +++++++++ docs/specs/ivshmem-2-device-spec.md | 333 +++++++++ hw/misc/Makefile.objs | 2 +- hw/misc/ivshmem2.c | 1091 +++++++++++++++++++++++++++++ include/hw/misc/ivshmem2.h | 48 ++ 11 files changed, 2412 insertions(+), 1 deletion(-) create mode 100644 contrib/ivshmem2-server/Makefile.objs create mode 100644 contrib/ivshmem2-server/ivshmem2-server.c create mode 100644 contrib/ivshmem2-server/ivshmem2-server.h create mode 100644 contrib/ivshmem2-server/main.c create mode 100644 docs/specs/ivshmem-2-device-spec.md create mode 100644 hw/misc/ivshmem2.c create mode 100644 include/hw/misc/ivshmem2.h -- 2.16.4