From patchwork Wed Oct 16 20:40:36 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Henrique Barboza X-Patchwork-Id: 13838940 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 700D7D1AD45 for ; Wed, 16 Oct 2024 20:43:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t1Apl-0004cZ-AS; Wed, 16 Oct 2024 16:41:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t1Apk-0004c0-Kn for qemu-devel@nongnu.org; Wed, 16 Oct 2024 16:41:28 -0400 Received: from mail-pj1-x1030.google.com ([2607:f8b0:4864:20::1030]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1t1Api-0004iM-ME for qemu-devel@nongnu.org; Wed, 16 Oct 2024 16:41:28 -0400 Received: by mail-pj1-x1030.google.com with SMTP id 98e67ed59e1d1-2e2bb1efe78so157909a91.1 for ; Wed, 16 Oct 2024 13:41:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ventanamicro.com; s=google; t=1729111285; x=1729716085; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=I4xBP2QStnLr7rsEthjKQX61QbXunCSIN41n1uqfLQg=; b=FgZM/aml9ic+0YEgZlhRa3N/DlKr8DjHqHrkVUPneXToKT9Sp0w+U5en+LBMrpTUd9 0xLeJJ/0fZ/Ysj2b0E/jBh8+Tmg3+rEP2bDF9qzDHFbvMEud3IyJCoM2yB94LIECBmyl S83JDJ8f0UXsi3Tec22EYAI1mFcZN8+dycsOdI5jbKGzgCYVslQdZdbsB3cg1JKNeEd9 BwHyTNU9ZIlyIxDhuhzdUUnwhkNJhpxW7NUmod3/pphvXssfhRSM4YpXuo6EAi6D+1Gu EEghLdqfYg1eEgMlMbF+UVG3v2yhz9wFAO05p+rcC1TsisHvsEA8pDI6vnTtCloDBmTL 5MsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729111285; x=1729716085; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=I4xBP2QStnLr7rsEthjKQX61QbXunCSIN41n1uqfLQg=; b=UVLtsoiDI/FnTSGUj2UyhZNGaqq5bjtGsoehDzajAWAf7r3UdUOq72BZhNmEPvvTXu VjmQhZzCWe3G8iHk9Br75/uykbwyNKLPARp4ZQ9a4W2yGnZrFilhntBSsCtiWWxuL+8j ojM54p4GeQJFssmouxQTfiP7gynggbcST43IcA1cI7/0s0jIvzUG3UXHoKg/t32mcZQj igt+AJmy2J1OWeFGZp5XREC4lIy2V6M47CusLXcCXoNrZRBD8SkMLKOtzAd//SIb/EnM W1O43naFiJtja/E95F/HxBeGba3WS/OtgD7QJ3DfDt3+hB0RLLKNSmee4DkbeRMAVIGn Dedw== X-Gm-Message-State: AOJu0Yzjji52FY+43mnIC7iBpliQ6cYR66pW4KOptX4UYdZZOh8Qug5r ZIztk681V3qVNLl64rV6NqaJxZgnDSjAfUav+5bIZkPPGZ1H9V/lWSJfjnz/Jhrlsa5EVuV7YNC 8 X-Google-Smtp-Source: AGHT+IEhJOOXG8gdPWb0gJ7hTfUSuLX9TYmLeMf0GlFNruu8KtJBPpi+UHRprZrYBdfYcWYWdBPoTA== X-Received: by 2002:a17:90a:fa98:b0:2e0:8780:ecb with SMTP id 98e67ed59e1d1-2e3dc277e05mr1324536a91.12.1729111285016; Wed, 16 Oct 2024 13:41:25 -0700 (PDT) Received: from grind.dc1.ventanamicro.com ([177.188.133.9]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e3e09085cfsm242158a91.54.2024.10.16.13.41.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Oct 2024 13:41:24 -0700 (PDT) From: Daniel Henrique Barboza To: qemu-devel@nongnu.org Cc: qemu-riscv@nongnu.org, alistair.francis@wdc.com, bmeng@tinylab.org, liwei1518@gmail.com, zhiwei_liu@linux.alibaba.com, palmer@rivosinc.com, Daniel Henrique Barboza Subject: [PATCH v10 12/12] docs/specs: add riscv-iommu Date: Wed, 16 Oct 2024 17:40:36 -0300 Message-ID: <20241016204038.649340-13-dbarboza@ventanamicro.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241016204038.649340-1-dbarboza@ventanamicro.com> References: <20241016204038.649340-1-dbarboza@ventanamicro.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::1030; envelope-from=dbarboza@ventanamicro.com; helo=mail-pj1-x1030.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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Add a simple guideline to use the existing RISC-V IOMMU support we just added. This doc will be updated once we add the riscv-iommu-sys device. Signed-off-by: Daniel Henrique Barboza Reviewed-by: Alistair Francis --- docs/specs/index.rst | 1 + docs/specs/riscv-iommu.rst | 90 ++++++++++++++++++++++++++++++++++++++ docs/system/riscv/virt.rst | 13 ++++++ 3 files changed, 104 insertions(+) create mode 100644 docs/specs/riscv-iommu.rst diff --git a/docs/specs/index.rst b/docs/specs/index.rst index 6495ed5ed9..ff5a1f03da 100644 --- a/docs/specs/index.rst +++ b/docs/specs/index.rst @@ -36,3 +36,4 @@ guest hardware that is specific to QEMU. vmgenid rapl-msr rocker + riscv-iommu diff --git a/docs/specs/riscv-iommu.rst b/docs/specs/riscv-iommu.rst new file mode 100644 index 0000000000..463f4cffb6 --- /dev/null +++ b/docs/specs/riscv-iommu.rst @@ -0,0 +1,90 @@ +.. _riscv-iommu: + +RISC-V IOMMU support for RISC-V machines +======================================== + +QEMU implements a RISC-V IOMMU emulation based on the RISC-V IOMMU spec +version 1.0 `iommu1.0`_. + +The emulation includes a PCI reference device, riscv-iommu-pci, that QEMU +RISC-V boards can use. The 'virt' RISC-V machine is compatible with this +device. + +riscv-iommu-pci reference device +-------------------------------- + +This device implements the RISC-V IOMMU emulation as recommended by the section +"Integrating an IOMMU as a PCIe device" of `iommu1.0`_: a PCI device with base +class 08h, sub-class 06h and programming interface 00h. + +As a reference device it doesn't implement anything outside of the specification, +so it uses a generic default PCI ID given by QEMU: 1b36:0014. + +To include the device in the 'virt' machine: + +.. code-block:: bash + + $ qemu-system-riscv64 -M virt -device riscv-iommu-pci,[optional_pci_opts] (...) + +This will add a RISC-V IOMMU PCI device in the board following any additional +PCI parameters (like PCI bus address). The behavior of the RISC-V IOMMU is +defined by the spec but its operation is OS dependent. + +As of this writing the existing Linux kernel support `linux-v8`_, not yet merged, +does not have support for features like VFIO passthrough. The IOMMU emulation +was tested using a public Ventana Micro Systems kernel repository in +`ventana-linux`_. This kernel is based on `linux-v8`_ with additional patches that +enable features like KVM VFIO passthrough with irqbypass. Until the kernel support +is feature complete feel free to use the kernel available in the Ventana Micro Systems +mirror. + +The current Linux kernel support will use the IOMMU device to create IOMMU groups +with any eligible cards available in the system, regardless of factors such as the +order in which the devices are added in the command line. + +This means that these command lines are equivalent as far as the current +IOMMU kernel driver behaves: + +.. code-block:: bash + + $ qemu-system-riscv64 \ + -M virt,aia=aplic-imsic,aia-guests=5 \ + -device riscv-iommu-pci,addr=1.0,vendor-id=0x1efd,device-id=0xedf1 \ + -device e1000e,netdev=net1 -netdev user,id=net1,net=192.168.0.0/24 \ + -device e1000e,netdev=net2 -netdev user,id=net2,net=192.168.200.0/24 \ + (...) + + $ qemu-system-riscv64 \ + -M virt,aia=aplic-imsic,aia-guests=5 \ + -device e1000e,netdev=net1 -netdev user,id=net1,net=192.168.0.0/24 \ + -device e1000e,netdev=net2 -netdev user,id=net2,net=192.168.200.0/24 \ + -device riscv-iommu-pci,addr=1.0,vendor-id=0x1efd,device-id=0xedf1 \ + (...) + +Both will create iommu groups for the two e1000e cards. + +Another thing to notice on `linux-v8`_ and `ventana-linux`_ is that the kernel driver +considers an IOMMU identified as a Rivos device, i.e. it uses Rivos vendor ID. To +use the riscv-iommu-pci device with the existing kernel support we need to emulate +a Rivos PCI IOMMU by setting 'vendor-id' and 'device-id': + +.. code-block:: bash + + $ qemu-system-riscv64 -M virt \ + -device riscv-iommu-pci,vendor-id=0x1efd,device-id=0xedf1 (...) + +Several options are available to control the capabilities of the device, namely: + +- "bus": the bus that the IOMMU device uses +- "ioatc-limit": size of the Address Translation Cache (default to 2Mb) +- "intremap": enable/disable MSI support +- "ats": enable ATS support +- "off" (Out-of-reset translation mode: 'on' for DMA disabled, 'off' for 'BARE' (passthrough)) +- "s-stage": enable s-stage support +- "g-stage": enable g-stage support + +.. _iommu1.0: https://github.com/riscv-non-isa/riscv-iommu/releases/download/v1.0/riscv-iommu.pdf + +.. _linux-v8: https://lore.kernel.org/linux-riscv/cover.1718388908.git.tjeznach@rivosinc.com/ + +.. _ventana-linux: https://github.com/ventanamicro/linux/tree/dev-upstream diff --git a/docs/system/riscv/virt.rst b/docs/system/riscv/virt.rst index 9a06f95a34..8e9a2e4dda 100644 --- a/docs/system/riscv/virt.rst +++ b/docs/system/riscv/virt.rst @@ -84,6 +84,19 @@ none``, as in Firmware images used for pflash must be exactly 32 MiB in size. +riscv-iommu support +------------------- + +The board has support for the riscv-iommu-pci device by using the following +command line: + +.. code-block:: bash + + $ qemu-system-riscv64 -M virt -device riscv-iommu-pci (...) + +Refer to :ref:`riscv-iommu` for more information on how the RISC-V IOMMU support +works. + Machine-specific options ------------------------