February 2022 - Stratos-dev - op-lists.linaro.org

Xen Rust VirtIO demos work breakdown for Project Stratos

by Alex Bennée

Hi, The following is a breakdown (as best I can figure) of the work needed to demonstrate VirtIO backends in Rust on the Xen hypervisor. It requires work across a number of projects but notably core rust and virtio enabling in the Xen project (building on the work EPAM has already done) and the start of enabling rust-vmm crate to work with Xen. The first demo is a fairly simple toy to exercise the direct hypercall approach for a unikernel backend. On it's own it isn't super impressive but hopefully serves as a proof of concept for the idea of having backends running in a single exception level where latency will be important. The second is a much more ambitious bridge between Xen and vhost-user to allow for re-use of the existing vhost-user backends with the bridge acting as a proxy for what would usually be a full VMM in the type-2 hypervisor case. With that in mind the rust-vmm work is only aimed at doing the device emulation and doesn't address the larger question of how type-1 hypervisors can be integrated into the rust-vmm hypervisor model. A quick note about the estimates. They are exceedingly rough guesses plucked out of the air and I would be grateful for feedback from the appropriate domain experts on if I'm being overly optimistic or pessimistic. The links to the Stratos JIRA should be at least read accessible to all although they contain the same information as the attached document (albeit with nicer PNG renderings of my ASCII art ;-). There is a Stratos sync-up call next Thursday: https://calendar.google.com/event?action=TEMPLATE&tmeid=MWpidm5lbzM5NjlydnA… and I'm sure there will also be discussion in the various projects (hence the wide CC list). The Stratos calls are open to anyone who wants to attend and we welcome feedback from all who are interested. So on with the work breakdown: ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ STRATOS PLANNING FOR 21 TO 22 Alex Bennée ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Table of Contents ───────────────── 1. Xen Rust Bindings ([STR-51]) .. 1. Upstream an "official" rust crate for Xen ([STR-52]) .. 2. Basic Hypervisor Interactions hypercalls ([STR-53]) .. 3. [#10] Access to XenStore service ([STR-54]) .. 4. VirtIO support hypercalls ([STR-55]) 2. Xen Hypervisor Support for Stratos ([STR-56]) .. 1. Stable ABI for foreignmemory mapping to non-dom0 ([STR-57]) .. 2. Tweaks to tooling to launch VirtIO guests 3. rust-vmm support for Xen VirtIO ([STR-59]) .. 1. Make vm-memory Xen aware ([STR-60]) .. 2. Xen IO notification and IRQ injections ([STR-61]) 4. Stratos Demos .. 1. Rust based stubdomain monitor ([STR-62]) .. 2. Xen aware vhost-user master ([STR-63]) 1 Xen Rust Bindings ([STR-51]) ══════════════════════════════ There exists a [placeholder repository] with the start of a set of x86_64 bindings for Xen and a very basic hello world uni-kernel example. This forms the basis of the initial Xen Rust work and will be available as a [xen-sys crate] via cargo. [STR-51] <https://linaro.atlassian.net/browse/STR-51> [placeholder repository] <https://gitlab.com/cardoe/oxerun.git> [xen-sys crate] <https://crates.io/crates/xen-sys> 1.1 Upstream an "official" rust crate for Xen ([STR-52]) ──────────────────────────────────────────────────────── To start with we will want an upstream location for future work to be based upon. The intention is the crate is independent of the version of Xen it runs on (above the baseline version chosen). This will entail: • ☐ agreeing with upstream the name/location for the source • ☐ documenting the rules for the "stable" hypercall ABI • ☐ establish an internal interface to elide between ioctl mediated and direct hypercalls • ☐ ensure the crate is multi-arch and has feature parity for arm64 As such we expect the implementation to be standalone, i.e. not wrapping the existing Xen libraries for mediation. There should be a close (1-to-1) mapping between the interfaces in the crate and the eventual hypercall made to the hypervisor. Estimate: 4w (elapsed likely longer due to discussion) [STR-52] <https://linaro.atlassian.net/browse/STR-52> 1.2 Basic Hypervisor Interactions hypercalls ([STR-53]) ─────────────────────────────────────────────────────── These are the bare minimum hypercalls implemented as both ioctl and direct calls. These allow for a very basic binary to: • ☐ console_io - output IO via the Xen console • ☐ domctl stub - basic stub for domain control (different API?) • ☐ sysctl stub - basic stub for system control (different API?) The idea would be this provides enough hypercall interface to query the list of domains and output their status via the xen console. There is an open question about if the domctl and sysctl hypercalls are way to go. Estimate: 6w [STR-53] <https://linaro.atlassian.net/browse/STR-53> 1.3 [#10] Access to XenStore service ([STR-54]) ─────────────────────────────────────────────── This is a shared configuration storage space accessed via either Unix sockets (on dom0) or via the Xenbus. This is used to access configuration information for the domain. Is this needed for a backend though? Can everything just be passed direct on the command line? Estimate: 4w [STR-54] <https://linaro.atlassian.net/browse/STR-54> 1.4 VirtIO support hypercalls ([STR-55]) ──────────────────────────────────────── These are the hypercalls that need to be implemented to support a VirtIO backend. This includes the ability to map another guests memory into the current domains address space, register to receive IOREQ events when the guest knocks at the doorbell and inject kicks into the guest. The hypercalls we need to support would be: • ☐ dmop - device model ops (*_ioreq_server, setirq, nr_vpus) • ☐ foreignmemory - map and unmap guest memory The DMOP space is larger than what we need for an IOREQ backend so I've based it just on what arch/arm/dm.c exports which is the subset introduced for EPAM's virtio work. Estimate: 12w [STR-55] <https://linaro.atlassian.net/browse/STR-55> 2 Xen Hypervisor Support for Stratos ([STR-56]) ═══════════════════════════════════════════════ These tasks include tasks needed to support the various different deployments of Stratos components in Xen. [STR-56] <https://linaro.atlassian.net/browse/STR-56> 2.1 Stable ABI for foreignmemory mapping to non-dom0 ([STR-57]) ─────────────────────────────────────────────────────────────── Currently the foreign memory mapping support only works for dom0 due to reference counting issues. If we are to support backends running in their own domains this will need to get fixed. Estimate: 8w [STR-57] <https://linaro.atlassian.net/browse/STR-57> 2.2 Tweaks to tooling to launch VirtIO guests ───────────────────────────────────────────── There might not be too much to do here. The EPAM work already did something similar for their PoC for virtio-block. Essentially we need to ensure: • ☐ DT bindings are passed to the guest for virtio-mmio device discovery • ☐ Our rust backend can be instantiated before the domU is launched This currently assumes the tools and the backend are running in dom0. Estimate: 4w 3 rust-vmm support for Xen VirtIO ([STR-59]) ════════════════════════════════════════════ This encompasses the tasks required to get a vhost-user server up and running while interfacing to the Xen hypervisor. This will require the xen-sys.rs crate for the actual interface to the hypervisor. We need to work out how a Xen configuration option would be passed to the various bits of rust-vmm when something is being built. [STR-59] <https://linaro.atlassian.net/browse/STR-59> 3.1 Make vm-memory Xen aware ([STR-60]) ─────────────────────────────────────── The vm-memory crate is the root crate for abstracting access to the guests memory. It currently has multiple configuration builds to handle difference between mmap on Windows and Unix. Although mmap isn't directly exposed the public interfaces support a mmap like interface. We would need to: • ☐ work out how to expose foreign memory via the vm-memory mechanism I'm not sure if this just means implementing the GuestMemory trait for a GuestMemoryXen or if we need to present a mmap like interface. Estimate: 8w [STR-60] <https://linaro.atlassian.net/browse/STR-60> 3.2 Xen IO notification and IRQ injections ([STR-61]) ───────────────────────────────────────────────────── The KVM world provides for ioeventfd (notifications) and irqfd (injection) to signal asynchronously between the guest and the backend. As far a I can tell this is currently handled inside the various VMMs which assume a KVM backend. While the vhost-user slave code doesn't see the register_ioevent/register_irqfd events it does deal with EventFDs throughout the code. Perhaps the best approach here would be to create a IOREQ crate that can create EventFD descriptors which can then be passed to the slaves to use for notification and injection. Otherwise there might be an argument for a new crate that can encapsulate this behaviour for both KVM/ioeventd and Xen/IOREQ setups? Estimate: 8w? [STR-61] <https://linaro.atlassian.net/browse/STR-61> 4 Stratos Demos ═══════════════ These tasks cover the creation of demos that brig together all the previous bits of work to demonstrate a new area of capability that has been opened up by Stratos work. 4.1 Rust based stubdomain monitor ([STR-62]) ──────────────────────────────────────────── This is a basic demo that is a proof of concept for a unikernel style backend written in pure Rust. This work would be a useful precursor for things such as the RTOS Dom0 on a safety island ([STR-11]) or as a carrier for the virtio-scmi backend. The monitor program will periodically poll the state of the other domains and echo their status to the Xen console. Estimate: 4w #+name: stub-domain-example #+begin_src ditaa :cmdline -o :file stub_domain_example.png Dom0 | DomU | DomStub | | : /-------------\ : | |cPNK | | | | | | | | | | /------------------------------------\ | | GuestOS | | |cPNK | | | | | EL0 | Dom0 Userspace (xl tools, QEMU) | | | | | /---------------\ | | | | | | |cYEL | \------------------------------------/ | | | | | | +------------------------------------+ | | | | | Rust Monitor | EL1 |cA1B Dom0 Kernel | | | | | | | +------------------------------------+ | \-------------/ | \---------------/ -------------------------------------------------------------------------------=------------------ +-------------------------------------------------------------------------------------+ EL2 |cC02 Xen Hypervisor | +-------------------------------------------------------------------------------------+ #+end_src [STR-62] <https://linaro.atlassian.net/browse/STR-62> [STR-11] <https://linaro.atlassian.net/browse/STR-11> 4.2 Xen aware vhost-user master ([STR-63]) ────────────────────────────────────────── Usually the master side of a vhost-user system is embedded directly in the VMM itself. However in a Xen deployment their is no overarching VMM but a series of utility programs that query the hypervisor directly. The Xen tooling is also responsible for setting up any support processes that are responsible for emulating HW for the guest. The task aims to bridge the gap between Xen's normal HW emulation path (ioreq) and VirtIO's userspace device emulation (vhost-user). The process would be started with some information on where the virtio-mmio address space is and what the slave binary will be. It will then: • map the guest into Dom0 userspace and attach to a MemFD • register the appropriate memory regions as IOREQ regions with Xen • create EventFD channels for the virtio kick notifications (one each way) • spawn the vhost-user slave process and mediate the notifications and kicks between the slave and Xen itself #+name: xen-vhost-user-master #+begin_src ditaa :cmdline -o :file xen_vhost_user_master.png Dom0 DomU | | | | | | +-------------------+ +-------------------+ | | |----------->| | | | vhost-user | vhost-user | vhost-user | : /------------------------------------\ | slave | protocol | master | | | | | (existing) |<-----------| (rust) | | | | +-------------------+ +-------------------+ | | | ^ ^ | ^ | | Guest Userspace | | | | | | | | | | | IOREQ | | | | | | | | | | | v v V | | \------------------------------------/ +---------------------------------------------------+ | +------------------------------------+ | ^ ^ | ioctl ^ | | | | | | iofd/irqfd eventFD | | | | | | Guest Kernel | | +---------------------------+ | | | | | +-------------+ | | | | | | | | virtio-dev | | | Host Kernel V | | | | +-------------+ | +---------------------------------------------------+ | +------------------------------------+ | ^ | | ^ | hyper | | | ----------------------=------------- | -=--- | ----=------ | -----=- | --------=------------------ | call | Trap | | IRQ V | V | +-------------------------------------------------------------------------------------+ | | ^ | ^ | | | +-------------+ | | EL2 | Xen Hypervisor | | | | +-------------------------------+ | | | +-------------------------------------------------------------------------------------+ #+end_src [STR-63] <https://linaro.atlassian.net/browse/STR-63> -- Alex Bennée

2 years

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[PATCH V2 0/4] libgpiod: Add Rust bindings

by Viresh Kumar

Hi Bartosz, This patch adds rust bindings for libgpiod v2.0, this is already partially tested with the virtio rust backend I am developing, which uses these to talk to the host kernel. This is based of the next/post-libgpiod-2.0 branch. I will be adding testing infrastructure later on, once other bindings are converted to use gpiosim. V1->V2: - Added examples (I tested everything except gpiomon.rs, didn't have right hardware/mock device to test). - Build rust bindings as part of Make, update documentation. Thanks. -- Viresh Viresh Kumar (4): libgpiod: Generate rust FFI bindings libgpiod: Add rust wrappers rust: Add examples rust: Integrate building of rust bindings with make .gitignore | 5 + README | 8 +- TODO | 8 - bindings/Makefile.am | 6 + bindings/rust/Cargo.toml | 14 + bindings/rust/Makefile.am | 29 ++ bindings/rust/build.rs | 60 ++++ bindings/rust/examples/gpiodetect.rs | 38 +++ bindings/rust/examples/gpiofind.rs | 43 +++ bindings/rust/examples/gpioget.rs | 45 +++ bindings/rust/examples/gpioinfo.rs | 90 ++++++ bindings/rust/examples/gpiomon.rs | 73 +++++ bindings/rust/examples/gpioset.rs | 55 ++++ bindings/rust/src/bindings.rs | 16 + bindings/rust/src/chip.rs | 197 ++++++++++++ bindings/rust/src/edge_event.rs | 78 +++++ bindings/rust/src/event_buffer.rs | 59 ++++ bindings/rust/src/info_event.rs | 70 +++++ bindings/rust/src/lib.rs | 268 +++++++++++++++++ bindings/rust/src/line_config.rs | 431 +++++++++++++++++++++++++++ bindings/rust/src/line_info.rs | 186 ++++++++++++ bindings/rust/src/line_request.rs | 217 ++++++++++++++ bindings/rust/src/request_config.rs | 118 ++++++++ bindings/rust/wrapper.h | 2 + configure.ac | 16 + 25 files changed, 2121 insertions(+), 11 deletions(-) create mode 100644 bindings/rust/Cargo.toml create mode 100644 bindings/rust/Makefile.am create mode 100644 bindings/rust/build.rs create mode 100644 bindings/rust/examples/gpiodetect.rs create mode 100644 bindings/rust/examples/gpiofind.rs create mode 100644 bindings/rust/examples/gpioget.rs create mode 100644 bindings/rust/examples/gpioinfo.rs create mode 100644 bindings/rust/examples/gpiomon.rs create mode 100644 bindings/rust/examples/gpioset.rs create mode 100644 bindings/rust/src/bindings.rs create mode 100644 bindings/rust/src/chip.rs create mode 100644 bindings/rust/src/edge_event.rs create mode 100644 bindings/rust/src/event_buffer.rs create mode 100644 bindings/rust/src/info_event.rs create mode 100644 bindings/rust/src/lib.rs create mode 100644 bindings/rust/src/line_config.rs create mode 100644 bindings/rust/src/line_info.rs create mode 100644 bindings/rust/src/line_request.rs create mode 100644 bindings/rust/src/request_config.rs create mode 100644 bindings/rust/wrapper.h -- 2.31.1.272.g89b43f80a514

2 years

5
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[PATCH 0/2] virtio: Add vhost-user-gpio device's support

by Viresh Kumar

Hello, This patchset adds vhost-user-gpio device's support in Qemu. The support for the same has already been added to virtio specification and Linux Kernel. A Rust based backend is also in progress and is tested against this patchset: https://github.com/rust-vmm/vhost-device/pull/76 -- Viresh Viresh Kumar (2): hw/virtio: add boilerplate for vhost-user-gpio device hw/virtio: add vhost-user-gpio-pci boilerplate hw/virtio/Kconfig | 5 + hw/virtio/meson.build | 2 + hw/virtio/vhost-user-gpio-pci.c | 69 ++++++ hw/virtio/vhost-user-gpio.c | 343 ++++++++++++++++++++++++++++ include/hw/virtio/vhost-user-gpio.h | 35 +++ 5 files changed, 454 insertions(+) create mode 100644 hw/virtio/vhost-user-gpio-pci.c create mode 100644 hw/virtio/vhost-user-gpio.c create mode 100644 include/hw/virtio/vhost-user-gpio.h -- 2.31.1.272.g89b43f80a514

2 years

3
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Metadata and signalling channels for Zephyr virtio-backends on Xen

by Alex Bennée

Hi Stefano, Vincent gave an update on his virtio-scmi work at the last Stratos sync call and the discussion moved onto next steps. Currently the demo setup is intermediated by a double-ended vhost-user daemon running on the devbox acting as a go between a number of QEMU instances representing the front and back-ends. You can view the architecture with Vincents diagram here: https://docs.google.com/drawings/d/1YSuJUSjEdTi2oEUq4oG4A9pBKSEJTAp6hhcHKKh… The key virtq handling is done over the special carve outs of shared memory between the front end and guest. However the signalling is currently over a virtio device on the backend. This is useful for the PoC but obviously in a real system we don't have a hidden POSIX system acting as a go between not to mention the additional latency it causes with all those context switches. I was hoping we could get some more of the Xen experts to the next Stratos sync (17th Feb) to go over approaches for a properly hosted on Xen approach. From my recollection (Vincent please correct me if I'm wrong) of last week the issues that need solving are: * How to handle configuration steps as FE guests come up The SCMI server will be a long running persistent backend because it is managing real HW resources. However the guests may be ephemeral (or just restarted) so we can't just hard-code everything in a DTB. While the virtio-negotiation in the config space covers most things we still need information like where in the guests address space the shared memory lives and at what offset into that the queues are created. As far as I'm aware the canonical source of domain information is XenStore (https://wiki.xenproject.org/wiki/XenStore) but this relies on a Dom0 type approach. Is there an alternative for dom0less systems or do we need a dom0-light approach, for example using STR-21 (Ensure Zephyr can run cleanly as a Dom0 guest) providing just enough services for FE's to register metadata and BE's to read it? * How to handle mapping of memory AIUI the Xen model is the FE guest explicitly makes grant table requests to expose portions of it's memory to other domains. Can the BE query the hypervisor itself to discover the available grants or does it require coordination with Dom0/XenStore for that information to be available to the BE domain? * How to handle signalling I guess this requires a minimal implementation of the IOREQ calls for Zephyr so we can register the handler in the backend? Does the IOREQ API allow for a IPI style notifications using the global GIC IRQs? Forgive the incomplete notes from the Stratos sync, I was trying to type while participating in the discussion so hopefully this email captures what was missed: https://linaro.atlassian.net/wiki/spaces/STR/pages/28682518685/2022-02-03+P… Vincent, anything to add? -- Alex Bennée

2 years, 2 months

4
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Unblocking multi-block virtio-rpmb

by Alex Bennée

Hi Ruchika, I just wanted to check what was required for you to make progress using virtio-rpmb. We've updated the spec for multi-block and I think implementing it in the C version of the backend is pretty trivial. The main thing I need is a decent way to test it. The original backend was tested with the out of tree virtio-rpmb driver which I hacked up to meet the spec. However my proposal for a new kernel ABI fell flat: Subject: [RFC PATCH 0/5] RPMB internal and user-space API + WIP virtio-rpmb frontend Date: Wed, 3 Mar 2021 13:54:55 +0000 Message-Id: <20210303135500.24673-1-alex.bennee(a)linaro.org> the main issue being not wanting to delegate crypto to inside the kernel. So we need to return to doing the frame calculations externally to the kernel and it simply acting as a conduit for the virtio frames. I can just hack up my original test branch for multi-block although it seems such a driver is unlikely to be merged anyway so it would just be an out-of-tree testing branch. Ilias mentioned we could test if he completes his uboot driver but I recall there where some questions about how it fitted into u-boots driver structure (i.e. being treated as a real device). For your work do you still need a Linux driver for the rpmb anyway? -- Alex Bennée

2 years, 2 months

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Updated dockerfiles

by Alex Bennée

Viresh, Apologies for the messy nature of my docker repo but there is a new image: https://github.com/stsquad/dockerfiles/tree/master/crossbuild/bullseye-arm64 which I have confirmed can build current Xen master: make[4]: Leaving directory '/home/alex.bennee/lsrc/xen/xen.build.arm64-xen-master-for-bullseye/tools/pygrub' make[3]: Leaving directory '/home/alex.bennee/lsrc/xen/xen.build.arm64-xen-master-for-bullseye/tools' make[2]: Leaving directory '/home/alex.bennee/lsrc/xen/xen.build.arm64-xen-master-for-bullseye/tools' make[1]: Leaving directory '/home/alex.bennee/lsrc/xen/xen.build.arm64-xen-master-for-bullseye/tools' fakeroot sh ./tools/misc/mkdeb /home/alex.bennee/lsrc/xen/xen.build.arm64-xen-master-for-bullseye $(make -C xen xenversion --no-print-directory) dpkg-deb: building package 'xen-upstream' in 'xen-upstream-4.17-unstable.deb'. 🕙14:00:03 alex.bennee@4372e168fe23:xen.build.arm64-xen-master-for-bullseye on  xen.build.arm64-xen-master-for-bullseye [?] took 31s ➜ ls -l dist/ total 24667 -rw-r--r-- 1 alex.bennee alex.bennee 20830 Jun 7 2021 COPYING -rw-r--r-- 1 alex.bennee alex.bennee 8632 Jun 7 2021 README drwxr-xr-x 6 alex.bennee alex.bennee 6 Feb 11 13:59 install/ -rwxr-xr-x 1 alex.bennee alex.bennee 658 Jun 7 2021 install.sh* -rw-r--r-- 1 alex.bennee alex.bennee 25213092 Feb 11 14:00 xen-upstream-4.17-unstable.deb -- Alex Bennée

2 years, 2 months

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[PATCH V2] hw/vhost-user-i2c: Add support for VIRTIO_I2C_F_ZERO_LENGTH_REQUEST

by Viresh Kumar

VIRTIO_I2C_F_ZERO_LENGTH_REQUEST is a mandatory feature, that must be implemented by everyone. Add its support. Reviewed-by: Alex Bennée <alex.bennee(a)linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar(a)linaro.org> --- V2: - Add missing VHOST_INVALID_FEATURE_BIT. - Add reviewed-by tag. hw/virtio/vhost-user-i2c.c | 11 +++++++++-- include/hw/virtio/vhost-user-i2c.h | 3 +++ 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/hw/virtio/vhost-user-i2c.c b/hw/virtio/vhost-user-i2c.c index d172632bb0cd..42c7f6d9e5bb 100644 --- a/hw/virtio/vhost-user-i2c.c +++ b/hw/virtio/vhost-user-i2c.c @@ -19,6 +19,11 @@ #define VIRTIO_ID_I2C_ADAPTER 34 #endif +static const int feature_bits[] = { + VIRTIO_I2C_F_ZERO_LENGTH_REQUEST, + VHOST_INVALID_FEATURE_BIT +}; + static void vu_i2c_start(VirtIODevice *vdev) { BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); @@ -113,8 +118,10 @@ static void vu_i2c_set_status(VirtIODevice *vdev, uint8_t status) static uint64_t vu_i2c_get_features(VirtIODevice *vdev, uint64_t requested_features, Error **errp) { - /* No feature bits used yet */ - return requested_features; + VHostUserI2C *i2c = VHOST_USER_I2C(vdev); + + virtio_add_feature(&requested_features, VIRTIO_I2C_F_ZERO_LENGTH_REQUEST); + return vhost_get_features(&i2c->vhost_dev, feature_bits, requested_features); } static void vu_i2c_handle_output(VirtIODevice *vdev, VirtQueue *vq) diff --git a/include/hw/virtio/vhost-user-i2c.h b/include/hw/virtio/vhost-user-i2c.h index deae47a76d55..d8372f3b43ea 100644 --- a/include/hw/virtio/vhost-user-i2c.h +++ b/include/hw/virtio/vhost-user-i2c.h @@ -25,4 +25,7 @@ struct VHostUserI2C { bool connected; }; +/* Virtio Feature bits */ +#define VIRTIO_I2C_F_ZERO_LENGTH_REQUEST 0 + #endif /* _QEMU_VHOST_USER_I2C_H */ -- 2.31.1.272.g89b43f80a514

2 years, 2 months

1
0
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[PATCH] hw/vhost-user-i2c: Add support for VIRTIO_I2C_F_ZERO_LENGTH_REQUEST

by Viresh Kumar

VIRTIO_I2C_F_ZERO_LENGTH_REQUEST is a mandatory feature, that must be implemented by everyone. Add its support. Signed-off-by: Viresh Kumar <viresh.kumar(a)linaro.org> --- hw/virtio/vhost-user-i2c.c | 10 ++++++++-- include/hw/virtio/vhost-user-i2c.h | 3 +++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/hw/virtio/vhost-user-i2c.c b/hw/virtio/vhost-user-i2c.c index d172632bb0cd..6323a7203ae4 100644 --- a/hw/virtio/vhost-user-i2c.c +++ b/hw/virtio/vhost-user-i2c.c @@ -19,6 +19,10 @@ #define VIRTIO_ID_I2C_ADAPTER 34 #endif +static const int feature_bits[] = { + VIRTIO_I2C_F_ZERO_LENGTH_REQUEST +}; + static void vu_i2c_start(VirtIODevice *vdev) { BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); @@ -113,8 +117,10 @@ static void vu_i2c_set_status(VirtIODevice *vdev, uint8_t status) static uint64_t vu_i2c_get_features(VirtIODevice *vdev, uint64_t requested_features, Error **errp) { - /* No feature bits used yet */ - return requested_features; + VHostUserI2C *i2c = VHOST_USER_I2C(vdev); + + virtio_add_feature(&requested_features, VIRTIO_I2C_F_ZERO_LENGTH_REQUEST); + return vhost_get_features(&i2c->vhost_dev, feature_bits, requested_features); } static void vu_i2c_handle_output(VirtIODevice *vdev, VirtQueue *vq) diff --git a/include/hw/virtio/vhost-user-i2c.h b/include/hw/virtio/vhost-user-i2c.h index deae47a76d55..d8372f3b43ea 100644 --- a/include/hw/virtio/vhost-user-i2c.h +++ b/include/hw/virtio/vhost-user-i2c.h @@ -25,4 +25,7 @@ struct VHostUserI2C { bool connected; }; +/* Virtio Feature bits */ +#define VIRTIO_I2C_F_ZERO_LENGTH_REQUEST 0 + #endif /* _QEMU_VHOST_USER_I2C_H */ -- 2.31.1.272.g89b43f80a514

2 years, 2 months

2
3
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[PATCH 0/8] virtio: Add vhost-user based Video decode

by Peter Griffin

This series adds support for virtio-video decoder devices in Qemu and also provides a vhost-user-video vmm implementation. The vhost-user-video vmm currently parses virtio-vido v3 protocol (as that is what the Linux frontend driver implements). It then converts that to a v4l2 mem2mem stateful decoder device. Currently this has been tested using v4l2 vicodec test driver in Linux [1] but it is intended to be used with Arm SoCs which often implement v4l2 stateful decoders/encoders drivers for their video accelerators. The primary goal so far has been to allow continuing development of virtio-video Linux frontend driver and testing with Qemu. Using vicodec on the host allows a purely virtual dev env, and allows for ci integration in the future by kernelci etc. This series also adds the virtio_video.h header and adds the FWHT format which is used by vicodec driver. I have tested this VMM using v4l2-ctl from v4l2 utils in the guest to do a video decode to a file. This can then be validated using ffplay v4l2-compliance tool in the guest has also been run which stresses the interface and issues lots of syscall level tests See the README.md for example commands on how to configure guest kernel and do a video decode using Qemu, vicodec using this VMM. Linux virtio-video frontend driver code: https://github.com/petegriffin/linux/commits/v5.10-virtio-video-latest Qemu vmm code: https://github.com/petegriffin/qemu/tree/vhost-virtio-video-master-v1 This is part of a wider initiative by Linaro called "project Stratos" for which you can find information here: https://collaborate.linaro.org/display/STR/Stratos+Home Applies cleanly to git://git.qemu.org/qemu.git master(a3607def89). Thanks, Peter. [1] https://lwn.net/Articles/760650/ Peter Griffin (8): vhost-user-video: Add a README.md with cheat sheet of commands MAINTAINERS: Add virtio-video section vhost-user-video: boiler plate code for vhost-user-video device vhost-user-video: add meson subdir build logic standard-headers: Add virtio_video.h virtio_video: Add Fast Walsh-Hadamard Transform format hw/display: add vhost-user-video-pci tools/vhost-user-video: Add initial vhost-user-video vmm MAINTAINERS | 8 + hw/display/Kconfig | 5 + hw/display/meson.build | 3 + hw/display/vhost-user-video-pci.c | 82 + hw/display/vhost-user-video.c | 386 ++++ include/hw/virtio/vhost-user-video.h | 41 + include/standard-headers/linux/virtio_video.h | 484 +++++ tools/meson.build | 9 + tools/vhost-user-video/50-qemu-rpmb.json.in | 5 + tools/vhost-user-video/README.md | 98 + tools/vhost-user-video/main.c | 1680 ++++++++++++++++ tools/vhost-user-video/meson.build | 10 + tools/vhost-user-video/v4l2_backend.c | 1777 +++++++++++++++++ tools/vhost-user-video/v4l2_backend.h | 99 + tools/vhost-user-video/virtio_video_helpers.c | 462 +++++ tools/vhost-user-video/virtio_video_helpers.h | 166 ++ tools/vhost-user-video/vuvideo.h | 43 + 17 files changed, 5358 insertions(+) create mode 100644 hw/display/vhost-user-video-pci.c create mode 100644 hw/display/vhost-user-video.c create mode 100644 include/hw/virtio/vhost-user-video.h create mode 100644 include/standard-headers/linux/virtio_video.h create mode 100644 tools/vhost-user-video/50-qemu-rpmb.json.in create mode 100644 tools/vhost-user-video/README.md create mode 100644 tools/vhost-user-video/main.c create mode 100644 tools/vhost-user-video/meson.build create mode 100644 tools/vhost-user-video/v4l2_backend.c create mode 100644 tools/vhost-user-video/v4l2_backend.h create mode 100644 tools/vhost-user-video/virtio_video_helpers.c create mode 100644 tools/vhost-user-video/virtio_video_helpers.h create mode 100644 tools/vhost-user-video/vuvideo.h -- 2.25.1

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Stratos-dev February 2022