From patchwork Wed Feb 3 20:56:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dey, Megha" X-Patchwork-Id: 12065349 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA490C433E9 for ; Wed, 3 Feb 2021 21:03:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67E6F64F5F for ; Wed, 3 Feb 2021 21:03:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232681AbhBCVDA (ORCPT ); Wed, 3 Feb 2021 16:03:00 -0500 Received: from mga03.intel.com ([134.134.136.65]:47710 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232321AbhBCU6O (ORCPT ); Wed, 3 Feb 2021 15:58:14 -0500 IronPort-SDR: Mx4TZwhzE6zhEg/Myi6s2qaaTrU5h1/Gd54PVLrRBqeBCJJ2YhHjeyp3BRlZsiZIYDxp3ESzWG 9G/9BB56nptQ== X-IronPort-AV: E=McAfee;i="6000,8403,9884"; a="181190095" X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="181190095" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 12:57:32 -0800 IronPort-SDR: jF6G3NJzGgokGR6lD1hAvEKPFO/Fs2jX0KhiYC7l727N4wANLkAtlkN2UpSdny1JbD6Y9igX/z 65VuTxmCQpCw== X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="372510590" Received: from megha-z97x-ud7-th.sc.intel.com ([143.183.85.154]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-SHA; 03 Feb 2021 12:57:31 -0800 From: Megha Dey To: tglx@linutronix.de Cc: linux-kernel@vger.kernel.org, dave.jiang@intel.com, ashok.raj@intel.com, kevin.tian@intel.com, dwmw@amazon.co.uk, x86@kernel.org, tony.luck@intel.com, dan.j.williams@intel.com, megha.dey@intel.com, jgg@mellanox.com, kvm@vger.kernel.org, iommu@lists.linux-foundation.org, alex.williamson@redhat.com, bhelgaas@google.com, maz@kernel.org, linux-pci@vger.kernel.org, baolu.lu@linux.intel.com, ravi.v.shankar@intel.com, Leon Romanovsky Subject: [PATCH 11/12] platform-msi: Add platform check for subdevice irq domain Date: Wed, 3 Feb 2021 12:56:44 -0800 Message-Id: <1612385805-3412-12-git-send-email-megha.dey@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1612385805-3412-1-git-send-email-megha.dey@intel.com> References: <1612385805-3412-1-git-send-email-megha.dey@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Lu Baolu The pci_subdevice_msi_create_irq_domain() should fail if the underlying platform is not able to support IMS (Interrupt Message Storage). Otherwise, the isolation of interrupt is not guaranteed. For x86, IMS is only supported on bare metal for now. We could enable it in the virtualization environments in the future if interrupt HYPERCALL domain is supported or the hardware has the capability of interrupt isolation for subdevices. Cc: David Woodhouse Cc: Leon Romanovsky Cc: Kevin Tian Suggested-by: Thomas Gleixner Link: https://lore.kernel.org/linux-pci/87pn4nk7nn.fsf@nanos.tec.linutronix.de/ Link: https://lore.kernel.org/linux-pci/877dqrnzr3.fsf@nanos.tec.linutronix.de/ Link: https://lore.kernel.org/linux-pci/877dqqmc2h.fsf@nanos.tec.linutronix.de/ Signed-off-by: Lu Baolu Signed-off-by: Megha Dey --- arch/x86/pci/common.c | 74 +++++++++++++++++++++++++++++++++++++++++++++ drivers/base/platform-msi.c | 8 +++++ include/linux/msi.h | 1 + 3 files changed, 83 insertions(+) diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c index 3507f45..263ccf6 100644 --- a/arch/x86/pci/common.c +++ b/arch/x86/pci/common.c @@ -12,6 +12,8 @@ #include #include #include +#include +#include #include #include @@ -724,3 +726,75 @@ struct pci_dev *pci_real_dma_dev(struct pci_dev *dev) return dev; } #endif + +#ifdef CONFIG_DEVICE_MSI +/* + * We want to figure out which context we are running in. But the hardware + * does not introduce a reliable way (instruction, CPUID leaf, MSR, whatever) + * which can be manipulated by the VMM to let the OS figure out where it runs. + * So we go with the below probably on_bare_metal() function as a replacement + * for definitely on_bare_metal() to go forward only for the very simple reason + * that this is the only option we have. + */ +static const char * const vmm_vendor_name[] = { + "QEMU", "Bochs", "KVM", "Xen", "VMware", "VMW", "VMware Inc.", + "innotek GmbH", "Oracle Corporation", "Parallels", "BHYVE" +}; + +static void read_type0_virtual_machine(const struct dmi_header *dm, void *p) +{ + u8 *data = (u8 *)dm + 0x13; + + /* BIOS Information (Type 0) */ + if (dm->type != 0 || dm->length < 0x14) + return; + + /* Bit 4 of BIOS Characteristics Extension Byte 2*/ + if (*data & BIT(4)) + *((bool *)p) = true; +} + +static bool smbios_virtual_machine(void) +{ + bool bit_present = false; + + dmi_walk(read_type0_virtual_machine, &bit_present); + + return bit_present; +} + +static bool on_bare_metal(struct device *dev) +{ + int i; + + if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) + return false; + + if (smbios_virtual_machine()) + return false; + + if (iommu_capable(dev->bus, IOMMU_CAP_VIOMMU_HINT)) + return false; + + for (i = 0; i < ARRAY_SIZE(vmm_vendor_name); i++) + if (dmi_match(DMI_SYS_VENDOR, vmm_vendor_name[i])) + return false; + + pr_info("System running on bare metal, report to bugzilla.kernel.org if not the case."); + + return true; +} + +bool arch_support_pci_device_ims(struct pci_dev *pdev) +{ + /* + * When we are running in a VMM context, the device IMS could only be + * enabled when the underlying hardware supports interrupt isolation + * of the subdevice, or any mechanism (trap, hypercall) is added so + * that changes in the interrupt message store could be managed by the + * VMM. For now, we only support the device IMS when we are running on + * the bare metal. + */ + return on_bare_metal(&pdev->dev); +} +#endif diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c index 6127b3b..d5ae26f 100644 --- a/drivers/base/platform-msi.c +++ b/drivers/base/platform-msi.c @@ -519,6 +519,11 @@ struct irq_domain *device_msi_create_irq_domain(struct fwnode_handle *fn, #ifdef CONFIG_PCI #include +bool __weak arch_support_pci_device_ims(struct pci_dev *pdev) +{ + return false; +} + /** * pci_subdevice_msi_create_irq_domain - Create an irq domain for subdevices * @pdev: Pointer to PCI device for which the subdevice domain is created @@ -530,6 +535,9 @@ struct irq_domain *pci_subdevice_msi_create_irq_domain(struct pci_dev *pdev, struct irq_domain *domain, *pdev_msi; struct fwnode_handle *fn; + if (!arch_support_pci_device_ims(pdev)) + return NULL; + /* * Retrieve the MSI domain of the underlying PCI device's MSI * domain. The PCI device domain's parent domain is also the parent diff --git a/include/linux/msi.h b/include/linux/msi.h index a6b419d..fa02542 100644 --- a/include/linux/msi.h +++ b/include/linux/msi.h @@ -478,6 +478,7 @@ struct irq_domain *device_msi_create_irq_domain(struct fwnode_handle *fn, struct irq_domain *parent); # ifdef CONFIG_PCI +bool arch_support_pci_device_ims(struct pci_dev *pdev); struct irq_domain *pci_subdevice_msi_create_irq_domain(struct pci_dev *pdev, struct msi_domain_info *info); # endif