From patchwork Thu Apr 1 12:12:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Viresh Kumar X-Patchwork-Id: 413603 Delivered-To: patch@linaro.org Received: by 2002:a02:8562:0:0:0:0:0 with SMTP id g89csp499247jai; Thu, 1 Apr 2021 05:14:03 -0700 (PDT) X-Google-Smtp-Source: ABdhPJy2pG7PYrQsDFOV9hpP7LueGdCx/pQU6a5yjtk0PHeP6HVhDiLmVBMrBdxXbZGrJDh5JJDU X-Received: by 2002:a92:d78f:: with SMTP id d15mr6299408iln.112.1617279242918; Thu, 01 Apr 2021 05:14:02 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1617279242; cv=none; d=google.com; s=arc-20160816; b=e6J7pEkx+IxOJ3t8598Ywyn7Po2D4ZA86PQL69ALtcgM/L9XqN950FNBAcudYecRGO HmHk2B3jjLDlTChRoOeRSOnGmmM75qrbaFl6ftt24BfkYwhgjvhffwYoCclhNmpVWQwW jadeKX2JzGOF46paUdlDfhQ5e53GtUa2gpbSn9F2fX6vzkVB2z/bj5V+7DW69DXfDAaB Y1OCWZ/A8xh9vLOerQvKe5ka2G3pgunBxzR1cLLwJxzg0cMKh4DWg+M3kT5N4N5P+z0Y 9QYYgibgZdkOiQJU/UTLVekeC9qg+iBsZgKJjlOLtblPn/fNbJWGOEndDoSxMEjG4pqq xheg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:cc:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:content-transfer-encoding :mime-version:message-id:date:subject:to:from:dkim-signature; bh=PH6pdAQU7VJGHUl2onAKRx/bvuIswLWvVXxJ531T7NA=; b=P3+XldjuTX40TgTz6Reg+SMV9sjwS6MFj59gELnZ6d8Ud7BNSWpHj7vbQENHrFdSKu q94kBkQGuAptT70jvXhHfrOddcicFpSXEDrJCWdpwIVV//VbvuJ5s3GKuK1YhSLSjTvg Uk68ndcJzgTpbB0enmJzLJzf850Zp5zWkrzzdr6a3QeN+slxlRtGTQPp+y+FP++ojLY5 OxaM3Q6dKgovffd4uIbw4oX7ELbz11tlq7umxFIfD3WSET5IbtUodTjmdAmu81+Oodcu 6WpwS5ZBlHsLb72b4984vUWC9Dh0tcZJs+C8VrTkVPjVr6+vaq6Ix7WayTS8HPXMYp6l f5wg== ARC-Authentication-Results: i=1; mx.google.com; dkim=fail header.i=@linaro.org header.s=google header.b=i2BKlUxe; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from lists.gnu.org (lists.gnu.org. [209.51.188.17]) by mx.google.com with ESMTPS id v12si4763564jas.56.2021.04.01.05.14.02 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 01 Apr 2021 05:14:02 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; dkim=fail header.i=@linaro.org header.s=google header.b=i2BKlUxe; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: from localhost ([::1]:44660 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lRwD3-0000VC-UK for patch@linaro.org; Thu, 01 Apr 2021 08:14:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47698) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lRwCD-0000V2-G4 for qemu-devel@nongnu.org; Thu, 01 Apr 2021 08:13:09 -0400 Received: from mail-pj1-x1029.google.com ([2607:f8b0:4864:20::1029]:44960) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lRwCB-0004LV-8l for qemu-devel@nongnu.org; Thu, 01 Apr 2021 08:13:09 -0400 Received: by mail-pj1-x1029.google.com with SMTP id kk2-20020a17090b4a02b02900c777aa746fso913024pjb.3 for ; Thu, 01 Apr 2021 05:13:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=PH6pdAQU7VJGHUl2onAKRx/bvuIswLWvVXxJ531T7NA=; b=i2BKlUxeniCFwXdL2U/88Xa2RfqnaZ5+tUXB7WMHnVnkcUAygAH01G2JPA301ZRFjy aNeA1yEdgan2Lrja/urtHc2mwFfN64i8v28pxqngq9LJPwCHnLfAyvWm1aaPpX/DzuoF UsaYZW4LRtaDYICYSyNoXlPRc4BRV8hO2PywoJ/tIvXZ2mJJAInatWK2zM3bJMCIRUrn Exz4u7Gg92xv+o+kLP2IhtzPpv+qaSr7YfMWEBkj05/f6dOrrkXIj7yKM9biRC7lM0w1 CU40SJQUs8P8FI40XXRXrAL7acetPjujv6/MaQxaz9c+vgTFgZxT41vE4bWwRIWDUpOd nGRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=PH6pdAQU7VJGHUl2onAKRx/bvuIswLWvVXxJ531T7NA=; b=AW8DLcGxAaYsKHPJaqXCy3DoPjnX4dUi2r91/akqv8tJvepB2q/H5sYDPv8h91FU4H 8how8Ib/625lCQaJIqDlpPOiPcquURgO8Ynjhdc0osn1ocsP7sHln8xW3LAtXhlh32AS PFRMH+Ikt2GnZjHqf40KtvxcHTfiltT+qJPNeVofwu8G/ED1rGpQoEIQM0iIdTUAyWq6 QowAQ8tVlIhU6HLvOAojFiZfF/+POQMtFJouzEEhakvhQ4PZ1DF3TZlVUyxBXWACOBLp 7hDdCQxipOY9rzGudEODIUjmDhLEIVlScbH3ZuIcSxLDZ85gV7s100Exl8iw0Bb7xsqT hmKA== X-Gm-Message-State: AOAM531upezt5SX9DQBHovO/tPGaIjJNNF2QPdNR8bTC+EVzAXf0OjUs 9siG0ZkfI10kal/R9YkEqrAFFge6cW0PKw== X-Received: by 2002:a17:90a:5d14:: with SMTP id s20mr8673352pji.6.1617279184732; Thu, 01 Apr 2021 05:13:04 -0700 (PDT) Received: from localhost ([136.185.154.93]) by smtp.gmail.com with ESMTPSA id w84sm5439900pfc.142.2021.04.01.05.13.03 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 01 Apr 2021 05:13:04 -0700 (PDT) From: Viresh Kumar To: qemu-devel@nongnu.org, "Michael S. Tsirkin" , Viresh Kumar Subject: [PATCH V2 0/6] virtio: Implement generic vhost-user-i2c backend Date: Thu, 1 Apr 2021 17:42:29 +0530 Message-Id: X-Mailer: git-send-email 2.25.0.rc1.19.g042ed3e048af MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::1029; envelope-from=viresh.kumar@linaro.org; helo=mail-pj1-x1029.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Vincent Guittot , Jie Deng , Bill Mills , Arnd Bergmann , Mike Holmes , =?utf-8?q?Alex_Benn=C3=A9e?= , stratos-dev@op-lists.linaro.org Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" Hello, This is an initial implementation of a generic vhost-user backend for the I2C bus. This is based of the virtio specifications (already merged) for the I2C bus. The kernel virtio I2C driver is still under review, here is the latest version (v10): https://lore.kernel.org/lkml/226a8d5663b7bb6f5d06ede7701eedb18d1bafa1.1616493817.git.jie.deng@intel.com/ The backend is implemented as a vhost-user device because we want to experiment in making portable backends that can be used with multiple hypervisors. We also want to support backends isolated in their own separate service VMs with limited memory cross-sections with the principle guest. 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 I mentioned this to explain the decision to write the daemon as a fairly pure glib application that just depends on libvhost-user. We are not sure where the vhost-user backend should get queued, qemu or a separate repository. Similar questions were raised by an earlier thread by Alex Bennée for his RPMB work: https://lore.kernel.org/qemu-devel/20200925125147.26943-1-alex.bennee@linaro.org/ I2C Testing: ------------ I didn't have access to a real hardware where I can play with a I2C client device (like RTC, eeprom, etc) to verify the working of the backend daemon, so I decided to test it on my x86 box itself with hierarchy of two ARM64 guests. The first ARM64 guest was passed "-device ds1338,address=0x20" option, so it could emulate a ds1338 RTC device, which connects to an I2C bus. Once the guest came up, ds1338 device instance was created within the guest kernel by doing: echo ds1338 0x20 > /sys/bus/i2c/devices/i2c-0/new_device [ Note that this may end up binding the ds1338 device to its driver, which won't let our i2c daemon talk to the device. For that we need to manually unbind the device from the driver: echo 0-0020 > /sys/bus/i2c/devices/0-0020/driver/unbind ] After this is done, you will get /dev/rtc1. This is the device we wanted to emulate, which will be accessed by the vhost-user-i2c backend daemon via the /dev/i2c-0 file present in the guest VM. At this point we need to start the backend daemon and give it a socket-path to talk to from qemu (you can pass -v to it to get more detailed messages): vhost-user-i2c --socket-path=vi2c.sock --device-list 0:20 [ Here, 0:20 is the bus/device mapping, 0 for /dev/i2c-0 and 20 is client address of ds1338 that we used while creating the device. ] Now we need to start the second level ARM64 guest (from within the first guest) to get the i2c-virtio.c Linux driver up. The second level guest is passed the following options to connect to the same socket: -chardev socket,path=vi2c.sock,id=vi2c \ -device vhost-user-i2c-pci,chardev=vi2c,id=i2c Once the second level guest boots up, we will see the i2c-virtio bus at /sys/bus/i2c/devices/i2c-X/. From there we can now make it emulate the ds1338 device again by doing: echo ds1338 0x20 > /sys/bus/i2c/devices/i2c-0/new_device [ This time we want ds1338's driver to be bound to the device, so it should be enabled in the kernel as well. ] And we will get /dev/rtc1 device again here in the second level guest. Now we can play with the rtc device with help of hwclock utility and we can see the following sequence of transfers happening if we try to update rtc's time from system time. hwclock -w -f /dev/rtc1 (in guest2) -> Reaches i2c-virtio.c (Linux bus driver in guest2) -> transfer over virtio -> Reaches the qemu's vhost-i2c device emulation (running over guest1) -> Reaches the backend daemon vhost-user-i2c started earlier (in guest1) -> ioctl(/dev/i2c-0, I2C_RDWR, ..); (in guest1) -> reaches qemu's hw/rtc/ds1338.c (running over host) SMBUS Testing: -------------- I wasn't required to have such a tedious setup for testing out with SMBUS devices. I was able to emulate a SMBUS device on my x86 machine using i2c-stub driver. $ modprobe i2c-stub chip_addr=0x20 //Boot the arm64 guest now with i2c-virtio driver and then do: $ echo al3320a 0x20 > /sys/class/i2c-adapter/i2c-0/new_device $ cat /sys/bus/iio/devices/iio:device0/in_illuminance_raw That's it. I hope I was able to give a clear picture of my test setup here :) Thanks. V1->V2: - Add a separate patch (not to be merged) to keep stuff temporarily taken from Linux kernel. - Support SMBUS devices/busses in the backend daemon. - Fix lots of checkpatch warnings/errors. - Some other bug fixes, suggestions, etc. Viresh Kumar (6): !Merge: Update virtio headers from kernel hw/virtio: add boilerplate for vhost-user-i2c device hw/virtio: add vhost-user-i2c-pci boilerplate tools/vhost-user-i2c: Add backend driver docs: add a man page for vhost-user-i2c MAINTAINERS: Add entry for virtio-i2c MAINTAINERS | 9 + docs/tools/index.rst | 1 + docs/tools/vhost-user-i2c.rst | 75 ++ hw/virtio/Kconfig | 5 + hw/virtio/meson.build | 2 + hw/virtio/vhost-user-i2c-pci.c | 69 ++ hw/virtio/vhost-user-i2c.c | 285 +++++++ include/hw/virtio/vhost-user-i2c.h | 37 + include/standard-headers/linux/virtio_i2c.h | 40 + include/standard-headers/linux/virtio_ids.h | 1 + tools/meson.build | 8 + tools/vhost-user-i2c/50-qemu-i2c.json.in | 5 + tools/vhost-user-i2c/main.c | 809 ++++++++++++++++++++ tools/vhost-user-i2c/meson.build | 10 + 14 files changed, 1356 insertions(+) create mode 100644 docs/tools/vhost-user-i2c.rst create mode 100644 hw/virtio/vhost-user-i2c-pci.c create mode 100644 hw/virtio/vhost-user-i2c.c create mode 100644 include/hw/virtio/vhost-user-i2c.h create mode 100644 include/standard-headers/linux/virtio_i2c.h create mode 100644 tools/vhost-user-i2c/50-qemu-i2c.json.in create mode 100644 tools/vhost-user-i2c/main.c create mode 100644 tools/vhost-user-i2c/meson.build -- 2.25.0.rc1.19.g042ed3e048af