- Virtio-msg - lists.linaro.org

Notes and updated PR from Oct 23 meeting

by Bill Mills

All, The notes from today's meeting are on the wiki page: https://linaro.atlassian.net/wiki/spaces/HVAC/pages/30311874561/2025-10+Upd… PR #25 has been updated as discussed today and the PR header comment updated with changes. https://github.com/Linaro/virtio-msg-spec/pull/25 Thanks, Bill -- Bill Mills Principal Technical Consultant, Linaro +1-240-643-0836 TZ: US Eastern Work Schedule: Tues/Wed/Thur

31 minutes

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[PATCH v1 0/4] virtio: Add the virtio-msg transport

by Edgar E. Iglesias

Hi all, This the RFC I'm preparing to send to upstream QEMU for initial RFC review. A couple of limitations: I've not updated the protocol with the new msg_token field yet. We only support a single device per bus (dev_num = 0). The kernel driver only works as a module, when building it into the kernel it panics. ------------------- This adds virtio-msg, a new virtio transport. Virtio-msg works by exchanging messages over a bus and doesn't rely on trapping and emulating 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 would look if two SoC's would use virtio-msg across a PCI link. The virtio-msg spec: https://github.com/Linaro/virtio-msg-spec/ Linux with virtio-msg: https://github.com/edgarigl/linux/tree/edgari/virtio-msg-6.17 To try it, first build Linux with the following as modules: CONFIG_VIRTIO_MSG=m CONFIG_VIRTIO_MSG_AMP=m CONFIG_VIRTIO_MSG_AMP_PCI=m Boot linux in QEMU with a virtio-msg-amp-pci device, in this example with a virtio-net device attached to it (x86/q35 machine): -device virtio-msg-amp-pci -device virtio-net-device,netdev=n1,bus=/q35-pcihost/pcie.0/virtio-msg-amp-pci/vmsg.0 -netdev user,id=nc Modprobe: modprobe virtio_msg_transport.ko modprobe virtio_msg_amp.ko modprobe virtio_msg_amp_pci.ko You now should see the virtio device. Cheers, Edgar Edgar E. Iglesias (4): virtio: Introduce notify_queue virtio: Add virtio_queue_get_rings virtio: Add the virtio-msg transport virtio-msg-bus: amp-pci: Add generic AMP PCI device hw/misc/Kconfig | 7 + hw/misc/meson.build | 1 + hw/misc/virtio-msg-amp-pci.c | 324 ++++++++++++ hw/virtio/Kconfig | 4 + hw/virtio/meson.build | 5 + hw/virtio/virtio-msg-bus.c | 89 ++++ hw/virtio/virtio-msg.c | 596 ++++++++++++++++++++++ hw/virtio/virtio.c | 23 + include/hw/virtio/virtio-bus.h | 1 + include/hw/virtio/virtio-msg-bus.h | 95 ++++ include/hw/virtio/virtio-msg-prot.h | 747 ++++++++++++++++++++++++++++ include/hw/virtio/virtio-msg.h | 45 ++ include/hw/virtio/virtio.h | 2 + 13 files changed, 1939 insertions(+) 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/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

10 hours, 26 minutes

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Virtio Message Bus over FF-A 1.0 ALP0 released

by Bertrand Marquis

Hi Everyone, Today, Arm is releasing the first public version of the Virtio Message Bus over FF-A in version 1.0 and in quality state Alpha 0. The document is available for download here: https://developer.arm.com/documentation/den0153/0100 Please contact me if you have any comment, remarks, questions or improvements to suggest so that i can handle them before the spec reaches Beta quality. Regards Bertrand IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

2 days, 19 hours

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Notes and fixed up PR from meeting on 2025/10/16

by Bill Mills

All, The notes from the meeting are here: https://linaro.atlassian.net/wiki/spaces/HVAC/pages/30311874561/2025-10+Upd… PR #25 has been redone to include Bertrand's commits as well as my own. https://github.com/Linaro/virtio-msg-spec/pull/25 I am most interested to know everyones opinion on the removal of the redundant length fields. I am 60/40 against. Thanks, Bill -- Bill Mills Principal Technical Consultant, Linaro +1-240-643-0836 TZ: US Eastern Work Schedule: Tues/Wed/Thur

3 days, 18 hours

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Watch Live TV on Apple TV: Everything You Should Know

by andrew100mills＠gmail.com

Wondering does Apple TV have live TV? The answer is yes — but with a twist. Apple TV itself doesn’t stream live channels directly. Instead, it lets you access live TV through different apps and streaming services. Think of it as a smart hub that connects all your favorite entertainment in one place. You can watch live news, sports, and local channels using apps like YouTube TV, Hulu + Live TV, Sling TV, or fuboTV. These apps stream live content right through your Apple TV device, so you never miss your favorite shows or games. Plus, Apple TV’s clean interface and Siri voice control make browsing super easy and fun. If you’re subscribed to Apple TV+, you’ll get original series and movies, but not traditional live channels. To enjoy live TV, just download your preferred streaming app, sign in, and start watching. So, does Apple TV have live TV? Absolutely — through partner apps and services. It’s the perfect choice for cord-cutters who want flexibility, high quality, and convenience in one device. For more tech tips and guides like this, visit Home Tech Nerves and stay tuned for smarter streaming solutions! Visit Now: https://hometechnerves.com/does-apple-tv-have-live-tv/

2 weeks

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New pull request for RFCv3 spec

by Bertrand Marquis

Hi, I pushed the following pull request to github: https://github.com/Linaro/virtio-msg-spec/pull/24 It is a proposal to handle some things we agreed on modifying in the spec: - header size 8 byte - unique identifier in header - relax error handling to let bus report errors and be coherent with current linux implementation This is a draft and i am definitely open to comments :-) Cheers Bertrand IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

2 weeks

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[vmsg][RFC V2 PATCH 0/6] virtio: Add support for Virtio message transport

by Viresh Kumar

Hello, I will try to send this upstream early next week. V2: - Don't limit get/set config to 8 bytes only. - Improved direct/indirect message handling. - Take care of EBUSY error during indirect message. - Static assertions. -------------------------8<------------------------- Hello, This RFC series introduces support for a new Virtio transport type: "virtio-msg", as proposed in [1]. Unlike existing transport types like virtio-mmio or virtio-pci which rely on memory-mapped registers, virtio-msg implements transport operations via structured messages. Those messages can be transported through different mechanisms such as mailboxes, shared memory based FIFO or specific protocols such as FF-A on Arm. This series includes: - Core virtio-msg transport support. - Two message transport bus implementations: - virtio-msg-ffa: based on ARM's Firmware Framework for Arm (FF-A). - virtio-msg-loopback: a loopback device for testing and validation. The code is available here for reference: [3] and virtio-msg loopback test setup is explained here: [2]. This series is based on v6.16-rc6 and depends on commit [4] from linux-next. ### Memory Mapping and Reserved Memory Usage The first two patches enhance the reserved-memory subsystem to support attaching struct device`s that do not originate from DT nodes—essential for virtual or dynamically discovered devices like the FF-A or loopback buses. This reserved-memory region enables: - Restricting all DMA-coherent and streaming DMA memory to a controlled range. - Allowing the remote endpoint to pre-map this memory, reducing runtime overhead. - Preventing unintentional data leaks, since memory is typically shared at page granularity. - For the loopback bus, it restricts the portion of kernel memory that can be mapped into userspace, improving safety. Device association with reserved-memory regions is based on DT node naming conventions, such as vmsglb@ or vmsgffa@, similar to the remoteproc framework’s approach. Feedback on the design, API, and approach is welcome. -- Viresh [1] https://lore.kernel.org/all/20250620224426.3923880-2-bill.mills@linaro.org/ [2] https://linaro.atlassian.net/wiki/spaces/HVAC/pages/30104092673 [3] git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/linux.git virtio/msg-rfc-v1 [4] From linux-next: 5be53630b4f0 virtio-mmio: Remove virtqueue list from mmio device Viresh Kumar (6): of: reserved-memory: Add reserved_mem_device_init() of: reserved-memory: Add of_reserved_mem_lookup_by_name virtio: Add support for virtio-msg transport virtio-msg: Add optional userspace interface for message I/O virtio-msg: Add support for FF-A (Firmware Framework for Arm) bus virtio-msg: Add support for loopback bus MAINTAINERS | 7 + drivers/of/of_reserved_mem.c | 91 ++-- drivers/virtio/Kconfig | 34 ++ drivers/virtio/Makefile | 5 + drivers/virtio/virtio_msg.c | 611 +++++++++++++++++++++++++++ drivers/virtio/virtio_msg.h | 88 ++++ drivers/virtio/virtio_msg_ffa.c | 505 ++++++++++++++++++++++ drivers/virtio/virtio_msg_loopback.c | 323 ++++++++++++++ drivers/virtio/virtio_msg_user.c | 119 ++++++ include/linux/of_reserved_mem.h | 13 + include/uapi/linux/virtio_msg.h | 221 ++++++++++ include/uapi/linux/virtio_msg_ffa.h | 94 +++++ include/uapi/linux/virtio_msg_lb.h | 22 + 13 files changed, 2109 insertions(+), 24 deletions(-) create mode 100644 drivers/virtio/virtio_msg.c create mode 100644 drivers/virtio/virtio_msg.h create mode 100644 drivers/virtio/virtio_msg_ffa.c create mode 100644 drivers/virtio/virtio_msg_loopback.c create mode 100644 drivers/virtio/virtio_msg_user.c create mode 100644 include/uapi/linux/virtio_msg.h create mode 100644 include/uapi/linux/virtio_msg_ffa.h create mode 100644 include/uapi/linux/virtio_msg_lb.h -- 2.31.1.272.g89b43f80a514

3 weeks, 2 days

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Release v0.6 of hvac-demo

by Bill Mills

All, I have pushed and tagged a new version of the hvac-demo repo. I have also updated the pre-built container image at: docker.io/wmills/hvac-demo Remember you may need to pull the container image again to see the new version: podman pull docker.io/wmills/hvac-demo - or - docker pull docker.io/wmills/hvac-demo Changes include: * added demo-loopback to show virtio-msg-loopback (based on Viresh's work) * added demo-amp-qemu-pci with virtio-msg-amp on an emulated pcie card in QEMU * renamed all the demos to describe the demo instead of numbers * rebased demo-ffa-xen to use Viresh's latest kernel and rust code * other demos are just renamed Old name New name ---------------------------------- new demo-loopback new demo-amp-qemu-pci demo1 demoo-ffa-xen demo2a (deleted) demo2b demo-proxy-qemu demo3 demo-amp-zephyr demo4 demo-amp-dual-linux The following issues are known: 1) demo-ffa-xen hangs or crashes 1 out of 5 or 10 times Just run again if you see this 2) ./Build all does not build linux-virtio-msg-v2, use ./Build all linux-virtio-msg-amp-v2 You do not need to build the demos to run them 3) The timeout in demo-amp-dual-linux to too short for VERY slow systems Most people won't see this issue. I was testing on a RPiv5 Fixes for the last two issues are in the wip-v0.6-fixes branch. -- Bill Mills Principal Technical Consultant, Linaro +1-240-643-0836 TZ: US Eastern Work Schedule: Tues/Wed/Thur

2 months, 2 weeks

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[RFC PATCH 0/6] virtio: Add support for Virtio message transport

by Viresh Kumar

Hello, This RFC series introduces support for a new Virtio transport type: "virtio-msg", as proposed in [1]. Unlike existing transport types like virtio-mmio or virtio-pci, which rely on memory-mapped registers, virtio-msg implements transport operations via structured messages. Those messages can be transported through different mechanisms such as mailboxes, shared memory based FIFO or specific protocols such as FF-A on Arm. This series includes: - Core virtio-msg transport support. - Two message transport bus implementations: - virtio-msg-ffa: based on ARM's Firmware Framework for Arm (FF-A). - virtio-msg-loopback: a loopback device for testing and validation. The code is available here for reference: [2] and virtio-msg loopback and FF-A test setups are explained here: [3] and [4]. This series is based on v6.16 and depends on commit [5]. ### Memory Mapping and Reserved Memory Usage The first two patches enhance the reserved-memory subsystem to support attaching struct device`s that do not originate from DT nodes — essential for virtual or dynamically discovered devices like the FF-A or loopback buses. This reserved-memory region enables: - Restricting all DMA-coherent and streaming DMA memory to a controlled range. - Allowing the remote endpoint to pre-map this memory, reducing runtime overhead. - Preventing unintentional data leaks, since memory is typically shared at page granularity. - For the loopback bus, it restricts the portion of kernel memory that can be mapped into userspace, improving safety. Device association with reserved-memory regions is based on DT node naming conventions, such as vmsglb@ or vmsgffa@, similar to the remoteproc framework’s approach. Feedback on the design, API, and approach is welcome. -- Viresh [1] https://lore.kernel.org/all/20250620224426.3923880-2-bill.mills@linaro.org/ [2] git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/linux.git virtio/msg-rfc-v1 [3] https://linaro.atlassian.net/wiki/spaces/HVAC/pages/30104092673 [4] https://linaro.atlassian.net/wiki/spaces/HVAC/pages/29657792513 [5] From linux-next: 5be53630b4f0 virtio-mmio: Remove virtqueue list from mmio device Viresh Kumar (6): of: reserved-memory: Add reserved_mem_device_init() of: reserved-memory: Add of_reserved_mem_lookup_by_name virtio: Add support for virtio-msg transport virtio-msg: Add optional userspace interface for message I/O virtio-msg: Add support for FF-A (Firmware Framework for Arm) bus virtio-msg: Add support for loopback bus MAINTAINERS | 7 + drivers/of/of_reserved_mem.c | 91 +++- drivers/virtio/Kconfig | 34 ++ drivers/virtio/Makefile | 5 + drivers/virtio/virtio_msg.c | 655 +++++++++++++++++++++++++++ drivers/virtio/virtio_msg_ffa.c | 505 +++++++++++++++++++++ drivers/virtio/virtio_msg_internal.h | 88 ++++ drivers/virtio/virtio_msg_loopback.c | 323 +++++++++++++ drivers/virtio/virtio_msg_user.c | 140 ++++++ include/linux/of_reserved_mem.h | 13 + include/uapi/linux/virtio_msg.h | 213 +++++++++ include/uapi/linux/virtio_msg_ffa.h | 94 ++++ include/uapi/linux/virtio_msg_lb.h | 22 + 13 files changed, 2166 insertions(+), 24 deletions(-) create mode 100644 drivers/virtio/virtio_msg.c create mode 100644 drivers/virtio/virtio_msg_ffa.c create mode 100644 drivers/virtio/virtio_msg_internal.h create mode 100644 drivers/virtio/virtio_msg_loopback.c create mode 100644 drivers/virtio/virtio_msg_user.c create mode 100644 include/uapi/linux/virtio_msg.h create mode 100644 include/uapi/linux/virtio_msg_ffa.h create mode 100644 include/uapi/linux/virtio_msg_lb.h -- 2.31.1.272.g89b43f80a514

2 months, 3 weeks

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[RFC PATCH 0/6] virtio: Add support for Virtio message transport

by Viresh Kumar

Hi everyone, Over the last few weeks, I have made numerous changes in the design and code to get it ready for mainline. I have now prepared the initial RFC patchset to be sent to LKML. Please have a look and provide your valuable feedback. -------------------------8<------------------------- Hello, This RFC series introduces support for a new Virtio transport type: "virtio-msg", as proposed in [1]. Unlike existing transport types like virtio-mmio or virtio-pci which rely on memory-mapped registers, virtio-msg implements transport operations via structured message exchanges using standard virtqueues. This series includes: - Core virtio-msg transport support. - Two message transport bus implementations: - virtio-msg-ffa: based on ARM's Firmware Framework for Arm (FF-A). - virtio-msg-loopback: a loopback device for testing and validation. The code is available here for reference: [3] and virtio-msg loopback test setup is explained here: [2]. This series is based on v6.16-rc6 and depends on commit [4] from linux-next. ### Memory Mapping and Reserved Memory Usage The first two patches enhance the reserved-memory subsystem to support attaching `struct device`s that do not originate from DT nodes—essential for virtual or dynamically discovered devices like the FF-A or loopback buses. This reserved-memory region enables: - Restricting all DMA-coherent and streaming DMA memory to a controlled range. - Allowing the remote endpoint to pre-map this memory, reducing runtime overhead. - Preventing unintentional data leaks, since memory is typically shared at page granularity. - For the loopback bus, it restricts the portion of kernel memory that can be mapped into userspace, improving safety. Feedback on the design, API, and approach is welcome. -- Viresh [1] https://lore.kernel.org/all/20250620224426.3923880-2-bill.mills@linaro.org/ [2] https://linaro.atlassian.net/wiki/spaces/HVAC/pages/30104092673 [3] git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/linux.git virtio/msg-rfc-v1 [4] From linux-next: 5be53630b4f0 virtio-mmio: Remove virtqueue list from mmio device Viresh Kumar (6): of: reserved-memory: Add reserved_mem_device_init() of: reserved-memory: Add of_reserved_mem_lookup_by_name virtio: Add support for virtio-msg transport virtio-msg: Add optional userspace interface for message I/O virtio-msg: Add support for FF-A (Firmware Framework for Arm) bus virtio-msg: Add support for loopback bus MAINTAINERS | 7 + drivers/of/of_reserved_mem.c | 91 +++-- drivers/virtio/Kconfig | 34 ++ drivers/virtio/Makefile | 5 + drivers/virtio/virtio_msg.c | 546 +++++++++++++++++++++++++++ drivers/virtio/virtio_msg.h | 88 +++++ drivers/virtio/virtio_msg_ffa.c | 501 ++++++++++++++++++++++++ drivers/virtio/virtio_msg_loopback.c | 323 ++++++++++++++++ drivers/virtio/virtio_msg_user.c | 119 ++++++ include/linux/of_reserved_mem.h | 13 + include/uapi/linux/virtio_msg.h | 221 +++++++++++ include/uapi/linux/virtio_msg_ffa.h | 94 +++++ include/uapi/linux/virtio_msg_lb.h | 22 ++ 13 files changed, 2040 insertions(+), 24 deletions(-) create mode 100644 drivers/virtio/virtio_msg.c create mode 100644 drivers/virtio/virtio_msg.h create mode 100644 drivers/virtio/virtio_msg_ffa.c create mode 100644 drivers/virtio/virtio_msg_loopback.c create mode 100644 drivers/virtio/virtio_msg_user.c create mode 100644 include/uapi/linux/virtio_msg.h create mode 100644 include/uapi/linux/virtio_msg_ffa.h create mode 100644 include/uapi/linux/virtio_msg_lb.h -- 2.31.1.272.g89b43f80a514

3 months

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2025

2024

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