From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 30C37D2ECF9 for ; Tue, 20 Jan 2026 06:44:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=e5zTidzD1l2EkEPlrmawzN2dIfFYQQCNH1hdqUaixrE=; b=PqXym6/lxF4sNua7+BvOO0P5hg ZKgxE6aNFqpkurbnR8qYmCFnJUuMbbIUB9R+8O75E8Q1aanA/LDeX2RLsQwuW/FYWwISU5FtLTnTv Y+yYMoqvugDbOwGc7YI7P3dYIU5Cpb7Do6Yrc5RPY2ggGLSQTL8/yvzPwqLLCTiyEzYUsmMXFeDNY Bm4sgHDr/oRCboMvk/cxqUKegqroQwnbfq6lqmRO97ELa3Nyk0rmCeBfHxUyvajeDve4bHredb3rH dRrwqwIdTv7uAMMettZLAuJVEyH6aFCJBk5xLxI3BpD8h2xHq7nncueG8UN8G+1EHHMYIzOpXH+bd 1pSIw9nw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vi5TI-00000003HxY-1aPn; Tue, 20 Jan 2026 06:44:12 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vi5Ss-00000003HUO-0APq for linux-arm-kernel@lists.infradead.org; Tue, 20 Jan 2026 06:43:52 +0000 Received: from mrdev.corp.microsoft.com (192-184-212-33.fiber.dynamic.sonic.net [192.184.212.33]) by linux.microsoft.com (Postfix) with ESMTPSA id E60DA20B7175; Mon, 19 Jan 2026 22:43:39 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com E60DA20B7175 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1768891420; bh=e5zTidzD1l2EkEPlrmawzN2dIfFYQQCNH1hdqUaixrE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UNMpFJkAxc0ipZ/uc95ODahk07NK6NWJyqWcGkaZVKyIZt1UDQiiBulzjGwCk91VX jt0oLrxXe6iYTsRwRbf+EqSpgCO1gfUoGkAjX1AJ38Zyc7EB7vv0f3UcxIZZ6sNoFr vdmcs3Bq/RId5HwNs85PYXjzf1VCUY/upizMZ+/c= From: Mukesh R To: linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-pci@vger.kernel.org, linux-arch@vger.kernel.org Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, longli@microsoft.com, catalin.marinas@arm.com, will@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, joro@8bytes.org, lpieralisi@kernel.org, kwilczynski@kernel.org, mani@kernel.org, robh@kernel.org, bhelgaas@google.com, arnd@arndb.de, nunodasneves@linux.microsoft.com, mhklinux@outlook.com, romank@linux.microsoft.com Subject: [PATCH v0 11/15] x86/hyperv: Build logical device ids for PCI passthru hcalls Date: Mon, 19 Jan 2026 22:42:26 -0800 Message-ID: <20260120064230.3602565-12-mrathor@linux.microsoft.com> X-Mailer: git-send-email 2.51.2.vfs.0.1 In-Reply-To: <20260120064230.3602565-1-mrathor@linux.microsoft.com> References: <20260120064230.3602565-1-mrathor@linux.microsoft.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260119_224346_203686_C0FC21C8 X-CRM114-Status: GOOD ( 17.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Mukesh Rathor On Hyper-V, most hypercalls related to PCI passthru to map/unmap regions, interrupts, etc need a device id as a parameter. A device id refers to a specific device. A device id is of two types: o Logical: used for direct attach (see below) hypercalls. A logical device id is a unique 62bit value that is created and sent during the initial device attach. Then all further communications (for interrupt remaps etc) must use this logical id. o PCI: used for device domain hypercalls such as map, unmap, etc. This is built using actual device BDF info. PS: Since an L1VH only supports direct attaches, a logical device id on an L1VH VM is always a VMBus device id. For non-L1VH cases, we just use PCI BDF info, altho not strictly needed, to build the logical device id. At a high level, Hyper-V supports two ways to do PCI passthru: 1. Device Domain: root must create a device domain in the hypervisor, and do map/unmap hypercalls for mapping and unmapping guest RAM. All hypervisor communications use device id of type PCI for identifying and referencing the device. 2. Direct Attach: the hypervisor will simply use the guest's HW page table for mappings, thus the host need not do map/unmap hypercalls. A direct attached device must be referenced via logical device id and never via the PCI device id. For an L1VH root/parent, Hyper-V only supports direct attaches. Signed-off-by: Mukesh Rathor --- arch/x86/hyperv/irqdomain.c | 60 ++++++++++++++++++++++++++++++--- arch/x86/include/asm/mshyperv.h | 14 ++++++++ 2 files changed, 70 insertions(+), 4 deletions(-) diff --git a/arch/x86/hyperv/irqdomain.c b/arch/x86/hyperv/irqdomain.c index ccbe5848a28f..33017aa0caa4 100644 --- a/arch/x86/hyperv/irqdomain.c +++ b/arch/x86/hyperv/irqdomain.c @@ -137,7 +137,7 @@ static int get_rid_cb(struct pci_dev *pdev, u16 alias, void *data) return 0; } -static union hv_device_id hv_build_devid_type_pci(struct pci_dev *pdev) +static u64 hv_build_devid_type_pci(struct pci_dev *pdev) { int pos; union hv_device_id hv_devid; @@ -197,7 +197,58 @@ static union hv_device_id hv_build_devid_type_pci(struct pci_dev *pdev) } out: - return hv_devid; + return hv_devid.as_uint64; +} + +/* Build device id for direct attached devices */ +static u64 hv_build_devid_type_logical(struct pci_dev *pdev) +{ + hv_pci_segment segment; + union hv_device_id hv_devid; + union hv_pci_bdf bdf = {.as_uint16 = 0}; + struct rid_data data = { + .bridge = NULL, + .rid = PCI_DEVID(pdev->bus->number, pdev->devfn) + }; + + segment = pci_domain_nr(pdev->bus); + bdf.bus = PCI_BUS_NUM(data.rid); + bdf.device = PCI_SLOT(data.rid); + bdf.function = PCI_FUNC(data.rid); + + hv_devid.as_uint64 = 0; + hv_devid.device_type = HV_DEVICE_TYPE_LOGICAL; + hv_devid.logical.id = (u64)segment << 16 | bdf.as_uint16; + + return hv_devid.as_uint64; +} + +/* Build device id after the device has been attached */ +u64 hv_build_devid_oftype(struct pci_dev *pdev, enum hv_device_type type) +{ + if (type == HV_DEVICE_TYPE_LOGICAL) { + if (hv_l1vh_partition()) + return hv_pci_vmbus_device_id(pdev); + else + return hv_build_devid_type_logical(pdev); + } else if (type == HV_DEVICE_TYPE_PCI) + return hv_build_devid_type_pci(pdev); + + return 0; +} +EXPORT_SYMBOL_GPL(hv_build_devid_oftype); + +/* Build device id for the interrupt path */ +static u64 hv_build_irq_devid(struct pci_dev *pdev) +{ + enum hv_device_type dev_type; + + if (hv_pcidev_is_attached_dev(pdev) || hv_l1vh_partition()) + dev_type = HV_DEVICE_TYPE_LOGICAL; + else + dev_type = HV_DEVICE_TYPE_PCI; + + return hv_build_devid_oftype(pdev, dev_type); } /* @@ -221,7 +272,7 @@ int hv_map_msi_interrupt(struct irq_data *data, msidesc = irq_data_get_msi_desc(data); pdev = msi_desc_to_pci_dev(msidesc); - hv_devid = hv_build_devid_type_pci(pdev); + hv_devid.as_uint64 = hv_build_irq_devid(pdev); cpu = cpumask_first(irq_data_get_effective_affinity_mask(data)); return hv_map_interrupt(hv_current_partition_id, hv_devid, false, cpu, @@ -296,7 +347,8 @@ static int hv_unmap_msi_interrupt(struct pci_dev *pdev, { union hv_device_id hv_devid; - hv_devid = hv_build_devid_type_pci(pdev); + hv_devid.as_uint64 = hv_build_irq_devid(pdev); + return hv_unmap_interrupt(hv_devid.as_uint64, irq_entry); } diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 0d7fdfb25e76..97477c5a8487 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -188,6 +188,20 @@ bool hv_vcpu_is_preempted(int vcpu); static inline void hv_apic_init(void) {} #endif +#if IS_ENABLED(CONFIG_HYPERV_IOMMU) +static inline bool hv_pcidev_is_attached_dev(struct pci_dev *pdev) +{ return false; } /* temporary */ +u64 hv_build_devid_oftype(struct pci_dev *pdev, enum hv_device_type type); +#else /* CONFIG_HYPERV_IOMMU */ +static inline bool hv_pcidev_is_attached_dev(struct pci_dev *pdev) +{ return false; } + +static inline u64 hv_build_devid_oftype(struct pci_dev *pdev, + enum hv_device_type type) +{ return 0; } + +#endif /* CONFIG_HYPERV_IOMMU */ + u64 hv_pci_vmbus_device_id(struct pci_dev *pdev); struct irq_domain *hv_create_pci_msi_domain(void); -- 2.51.2.vfs.0.1