On Tue, Oct 28, 2025 at 04:23:45PM +0100, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <edgar.iglesias@amd.com>
>
> This adds virtio-msg, a new virtio transport. Virtio-msg works by
> exchanging messages over a bus and doesn't rely on trapping and emulation
> making it a good fit for a number of applications such as AMP, real-time
> and safety applications.
>
> Together with the new transport, this series adds a PCI device that
> implements an AMP setup much like it could look if two SoC's would
> use virtio-msg across a PCI link.
>
> Current gaps and limitations:
> Shared memory FIFO layout likely to change in the future.
> Temporarily uses PCI Vendor Xilinx / Device 0x9039.
> Documentation.
I'm happy that the spec effort is making progress finally.
Do you want to repost a version aligned to the latest spec posted?
> The virtio-msg draft spec:
> https://github.com/Linaro/virtio-msg-spec/
>
> QEMU with these patches:
> https://github.com/edgarigl/qemu/tree/edgar/virtio-msg-rfc
>
> Linux with virtio-msg support:
> https://github.com/edgarigl/linux/tree/edgari/virtio-msg-6.17
>
> To try it, first build Linux with the following enabled:
> CONFIG_VIRTIO_MSG=y
> CONFIG_VIRTIO_MSG_AMP=y
> CONFIG_VIRTIO_MSG_AMP_PCI=y
>
> Boot linux on QEMU with a virtio-msg-amp-pci device, in this example
> with a virtio-net device attached to it:
>
> -device virtio-msg-amp-pci
> -device virtio-net-device,netdev=n0
> -netdev user,id=n0
>
> If you're running on a QEMU machine that has virtio-mmio enabled, e.g
> ARM virt, you'll need to specify the virtio-bus for the device, otherwise
> QEMU will connect it to virtio-mmio. For ARM virt machines:
>
> -device virtio-msg-amp-pci
> -device virtio-net-device,netdev=n0,bus=/gpex-pcihost/pcie.0/virtio-msg-amp-pci/fifo0/virtio-msg/bus0/virtio-msg-dev
> -netdev user,id=n0
>
> Cheers,
> Edgar
>
> Edgar E. Iglesias (5):
> virtio: Introduce notify_queue
> virtio: Add virtio_queue_get_rings
> virtio: Add the virtio-msg transport
> hw/misc: Add generic virtio-msg AMP PCI device
> docs: Describe virtio-msg-amp-pci
>
> .../devices/virtio/virtio-msg-amp-pci.rst | 70 ++
> hw/misc/Kconfig | 7 +
> hw/misc/meson.build | 1 +
> hw/misc/virtio-msg-amp-pci.c | 328 +++++++
> hw/virtio/Kconfig | 4 +
> hw/virtio/meson.build | 5 +
> hw/virtio/virtio-msg-bus.c | 89 ++
> hw/virtio/virtio-msg.c | 695 ++++++++++++++
> hw/virtio/virtio.c | 23 +
> include/hw/virtio/spsc_queue.h | 213 +++++
> include/hw/virtio/virtio-bus.h | 1 +
> include/hw/virtio/virtio-msg-bus.h | 95 ++
> include/hw/virtio/virtio-msg-prot.h | 846 ++++++++++++++++++
> include/hw/virtio/virtio-msg.h | 56 ++
> include/hw/virtio/virtio.h | 2 +
> 15 files changed, 2435 insertions(+)
> create mode 100644 docs/system/devices/virtio/virtio-msg-amp-pci.rst
> create mode 100644 hw/misc/virtio-msg-amp-pci.c
> create mode 100644 hw/virtio/virtio-msg-bus.c
> create mode 100644 hw/virtio/virtio-msg.c
> create mode 100644 include/hw/virtio/spsc_queue.h
> create mode 100644 include/hw/virtio/virtio-msg-bus.h
> create mode 100644 include/hw/virtio/virtio-msg-prot.h
> create mode 100644 include/hw/virtio/virtio-msg.h
>
> --
> 2.43.0