From patchwork Sat Feb 6 03:35:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jon Derrick X-Patchwork-Id: 12071875 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=-16.7 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 6522DC433E6 for ; Sat, 6 Feb 2021 03:39:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C01964DFA for ; Sat, 6 Feb 2021 03:39:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231345AbhBFDj1 (ORCPT ); Fri, 5 Feb 2021 22:39:27 -0500 Received: from mga03.intel.com ([134.134.136.65]:16481 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230094AbhBFDiM (ORCPT ); Fri, 5 Feb 2021 22:38:12 -0500 IronPort-SDR: gQKiccVqVw8ElFOxQQlmMOAmgFL64AZ1X5u9na+KxKOprfDRaZKJsc1xPpEvfLCbzzWhrbmSbn wm8bUjGqBenQ== X-IronPort-AV: E=McAfee;i="6000,8403,9886"; a="181581385" X-IronPort-AV: E=Sophos;i="5.81,156,1610438400"; d="scan'208";a="181581385" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Feb 2021 19:35:12 -0800 IronPort-SDR: WzWbLKo7EcLKowoDX25Phm/FJThn6RXakfrDo/QCc1DA2DXh3sE1MJjMf2fdWZwfz1q8LCeggZ BVkmI+pjLejA== X-IronPort-AV: E=Sophos;i="5.81,156,1610438400"; d="scan'208";a="576921857" Received: from rgrover1-mobl.amr.corp.intel.com (HELO jderrick-mobl.amr.corp.intel.com) ([10.209.102.94]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Feb 2021 19:35:12 -0800 From: Jon Derrick To: , Cc: Bjorn Helgaas , Lorenzo Pieralisi , Lu Baolu , Joerg Roedel , Nirmal Patel , Kapil Karkra , Jon Derrick , Joerg Roedel Subject: [PATCH v3 2/2] PCI: vmd: Disable MSI-X remapping when possible Date: Fri, 5 Feb 2021 20:35:02 -0700 Message-Id: <20210206033502.103964-3-jonathan.derrick@intel.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210206033502.103964-1-jonathan.derrick@intel.com> References: <20210206033502.103964-1-jonathan.derrick@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org VMD will retransmit child device MSI-X using its own MSI-X table and requester-id. This limits the number of MSI-X available to the whole child device domain to the number of VMD MSI-X interrupts. Some VMD devices have a mode where this remapping can be disabled, allowing child device interrupts to bypass processing with the VMD MSI-X domain interrupt handler and going straight the child device interrupt handler, allowing for better performance and scaling. The requester-id still gets changed to the VMD endpoint's requester-id, and the interrupt remapping handlers have been updated to properly set IRTE for child device interrupts to the VMD endpoint's context. Some VMD platforms have existing production BIOS which rely on MSI-X remapping and won't explicitly program the MSI-X remapping bit. This re-enables MSI-X remapping on unload. Acked-by: Joerg Roedel Signed-off-by: Jon Derrick Reviewed-by: Krzysztof Wilczyński --- drivers/pci/controller/vmd.c | 61 +++++++++++++++++++++++++++++------- 1 file changed, 49 insertions(+), 12 deletions(-) diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c index 5e80f28f0119..2a585d1b3349 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -28,6 +28,7 @@ #define BUS_RESTRICT_CAP(vmcap) (vmcap & 0x1) #define PCI_REG_VMCONFIG 0x44 #define BUS_RESTRICT_CFG(vmcfg) ((vmcfg >> 8) & 0x3) +#define VMCFG_MSI_RMP_DIS 0x2 #define PCI_REG_VMLOCK 0x70 #define MB2_SHADOW_EN(vmlock) (vmlock & 0x2) @@ -59,6 +60,13 @@ enum vmd_features { * be used for MSI remapping */ VMD_FEAT_OFFSET_FIRST_VECTOR = (1 << 3), + + /* + * Device can bypass remapping MSI-X transactions into its MSI-X table, + * avoiding the requirement of a VMD MSI domain for child device + * interrupt handling. + */ + VMD_FEAT_BYPASS_MSI_REMAP = (1 << 4), }; /* @@ -306,6 +314,15 @@ static struct msi_domain_info vmd_msi_domain_info = { .chip = &vmd_msi_controller, }; +static void vmd_enable_msi_remapping(struct vmd_dev *vmd, bool enable) +{ + u16 reg; + + pci_read_config_word(vmd->dev, PCI_REG_VMCONFIG, ®); + reg = enable ? (reg & ~VMCFG_MSI_RMP_DIS) : (reg | VMCFG_MSI_RMP_DIS); + pci_write_config_word(vmd->dev, PCI_REG_VMCONFIG, reg); +} + static int vmd_create_irq_domain(struct vmd_dev *vmd) { struct fwnode_handle *fn; @@ -325,6 +342,13 @@ static int vmd_create_irq_domain(struct vmd_dev *vmd) static void vmd_remove_irq_domain(struct vmd_dev *vmd) { + /* + * Some production BIOS won't enable remapping between soft reboots. + * Ensure remapping is restored before unloading the driver. + */ + if (!vmd->msix_count) + vmd_enable_msi_remapping(vmd, true); + if (vmd->irq_domain) { struct fwnode_handle *fn = vmd->irq_domain->fwnode; @@ -679,15 +703,31 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features) sd->node = pcibus_to_node(vmd->dev->bus); - ret = vmd_create_irq_domain(vmd); - if (ret) - return ret; - /* - * Override the irq domain bus token so the domain can be distinguished - * from a regular PCI/MSI domain. + * Currently MSI remapping must be enabled in guest passthrough mode + * due to some missing interrupt remapping plumbing. This is probably + * acceptable because the guest is usually CPU-limited and MSI + * remapping doesn't become a performance bottleneck. */ - irq_domain_update_bus_token(vmd->irq_domain, DOMAIN_BUS_VMD_MSI); + if (!(features & VMD_FEAT_BYPASS_MSI_REMAP) || offset[0] || offset[1]) { + ret = vmd_alloc_irqs(vmd); + if (ret) + return ret; + + vmd_enable_msi_remapping(vmd, true); + + ret = vmd_create_irq_domain(vmd); + if (ret) + return ret; + + /* + * Override the irq domain bus token so the domain can be + * distinguished from a regular PCI/MSI domain. + */ + irq_domain_update_bus_token(vmd->irq_domain, DOMAIN_BUS_VMD_MSI); + } else { + vmd_enable_msi_remapping(vmd, false); + } pci_add_resource(&resources, &vmd->resources[0]); pci_add_resource_offset(&resources, &vmd->resources[1], offset[0]); @@ -753,10 +793,6 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id) if (features & VMD_FEAT_OFFSET_FIRST_VECTOR) vmd->first_vec = 1; - err = vmd_alloc_irqs(vmd); - if (err) - return err; - spin_lock_init(&vmd->cfg_lock); pci_set_drvdata(dev, vmd); err = vmd_enable_domain(vmd, features); @@ -825,7 +861,8 @@ static const struct pci_device_id vmd_ids[] = { .driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP,}, {PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_VMD_28C0), .driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW | - VMD_FEAT_HAS_BUS_RESTRICTIONS,}, + VMD_FEAT_HAS_BUS_RESTRICTIONS | + VMD_FEAT_BYPASS_MSI_REMAP,}, {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x467f), .driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP | VMD_FEAT_HAS_BUS_RESTRICTIONS |