PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs
Add a new driver which exposes a root PCI bus whenever a PCI Express device
is passed through to a guest VM under Hyper-V. The device can be single-
or multi-function. The interrupts for the devices are managed by an IRQ
domain, implemented within the driver.
[bhelgaas: fold in race condition fix (http://lkml.kernel.org/r/1456340196-13717-1-git-send-email-jakeo@microsoft.com)]
Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
new file mode 100644
index 0000000..ed651ba
--- /dev/null
+++ b/drivers/pci/host/pci-hyperv.c
@@ -0,0 +1,2346 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Author:
+ * Jake Oshins <jakeo@microsoft.com>
+ *
+ * This driver acts as a paravirtual front-end for PCI Express root buses.
+ * When a PCI Express function (either an entire device or an SR-IOV
+ * Virtual Function) is being passed through to the VM, this driver exposes
+ * a new bus to the guest VM. This is modeled as a root PCI bus because
+ * no bridges are being exposed to the VM. In fact, with a "Generation 2"
+ * VM within Hyper-V, there may seem to be no PCI bus at all in the VM
+ * until a device as been exposed using this driver.
+ *
+ * Each root PCI bus has its own PCI domain, which is called "Segment" in
+ * the PCI Firmware Specifications. Thus while each device passed through
+ * to the VM using this front-end will appear at "device 0", the domain will
+ * be unique. Typically, each bus will have one PCI function on it, though
+ * this driver does support more than one.
+ *
+ * In order to map the interrupts from the device through to the guest VM,
+ * this driver also implements an IRQ Domain, which handles interrupts (either
+ * MSI or MSI-X) associated with the functions on the bus. As interrupts are
+ * set up, torn down, or reaffined, this driver communicates with the
+ * underlying hypervisor to adjust the mappings in the I/O MMU so that each
+ * interrupt will be delivered to the correct virtual processor at the right
+ * vector. This driver does not support level-triggered (line-based)
+ * interrupts, and will report that the Interrupt Line register in the
+ * function's configuration space is zero.
+ *
+ * The rest of this driver mostly maps PCI concepts onto underlying Hyper-V
+ * facilities. For instance, the configuration space of a function exposed
+ * by Hyper-V is mapped into a single page of memory space, and the
+ * read and write handlers for config space must be aware of this mechanism.
+ * Similarly, device setup and teardown involves messages sent to and from
+ * the PCI back-end driver in Hyper-V.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for more
+ * details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/semaphore.h>
+#include <linux/irqdomain.h>
+#include <asm/irqdomain.h>
+#include <asm/apic.h>
+#include <linux/msi.h>
+#include <linux/hyperv.h>
+#include <asm/mshyperv.h>
+
+/*
+ * Protocol versions. The low word is the minor version, the high word the
+ * major version.
+ */
+
+#define PCI_MAKE_VERSION(major, minor) ((u32)(((major) << 16) | (major)))
+#define PCI_MAJOR_VERSION(version) ((u32)(version) >> 16)
+#define PCI_MINOR_VERSION(version) ((u32)(version) & 0xff)
+
+enum {
+ PCI_PROTOCOL_VERSION_1_1 = PCI_MAKE_VERSION(1, 1),
+ PCI_PROTOCOL_VERSION_CURRENT = PCI_PROTOCOL_VERSION_1_1
+};
+
+#define PCI_CONFIG_MMIO_LENGTH 0x2000
+#define CFG_PAGE_OFFSET 0x1000
+#define CFG_PAGE_SIZE (PCI_CONFIG_MMIO_LENGTH - CFG_PAGE_OFFSET)
+
+#define MAX_SUPPORTED_MSI_MESSAGES 0x400
+
+/*
+ * Message Types
+ */
+
+enum pci_message_type {
+ /*
+ * Version 1.1
+ */
+ PCI_MESSAGE_BASE = 0x42490000,
+ PCI_BUS_RELATIONS = PCI_MESSAGE_BASE + 0,
+ PCI_QUERY_BUS_RELATIONS = PCI_MESSAGE_BASE + 1,
+ PCI_POWER_STATE_CHANGE = PCI_MESSAGE_BASE + 4,
+ PCI_QUERY_RESOURCE_REQUIREMENTS = PCI_MESSAGE_BASE + 5,
+ PCI_QUERY_RESOURCE_RESOURCES = PCI_MESSAGE_BASE + 6,
+ PCI_BUS_D0ENTRY = PCI_MESSAGE_BASE + 7,
+ PCI_BUS_D0EXIT = PCI_MESSAGE_BASE + 8,
+ PCI_READ_BLOCK = PCI_MESSAGE_BASE + 9,
+ PCI_WRITE_BLOCK = PCI_MESSAGE_BASE + 0xA,
+ PCI_EJECT = PCI_MESSAGE_BASE + 0xB,
+ PCI_QUERY_STOP = PCI_MESSAGE_BASE + 0xC,
+ PCI_REENABLE = PCI_MESSAGE_BASE + 0xD,
+ PCI_QUERY_STOP_FAILED = PCI_MESSAGE_BASE + 0xE,
+ PCI_EJECTION_COMPLETE = PCI_MESSAGE_BASE + 0xF,
+ PCI_RESOURCES_ASSIGNED = PCI_MESSAGE_BASE + 0x10,
+ PCI_RESOURCES_RELEASED = PCI_MESSAGE_BASE + 0x11,
+ PCI_INVALIDATE_BLOCK = PCI_MESSAGE_BASE + 0x12,
+ PCI_QUERY_PROTOCOL_VERSION = PCI_MESSAGE_BASE + 0x13,
+ PCI_CREATE_INTERRUPT_MESSAGE = PCI_MESSAGE_BASE + 0x14,
+ PCI_DELETE_INTERRUPT_MESSAGE = PCI_MESSAGE_BASE + 0x15,
+ PCI_MESSAGE_MAXIMUM
+};
+
+/*
+ * Structures defining the virtual PCI Express protocol.
+ */
+
+union pci_version {
+ struct {
+ u16 minor_version;
+ u16 major_version;
+ } parts;
+ u32 version;
+} __packed;
+
+/*
+ * Function numbers are 8-bits wide on Express, as interpreted through ARI,
+ * which is all this driver does. This representation is the one used in
+ * Windows, which is what is expected when sending this back and forth with
+ * the Hyper-V parent partition.
+ */
+union win_slot_encoding {
+ struct {
+ u32 func:8;
+ u32 reserved:24;
+ } bits;
+ u32 slot;
+} __packed;
+
+/*
+ * Pretty much as defined in the PCI Specifications.
+ */
+struct pci_function_description {
+ u16 v_id; /* vendor ID */
+ u16 d_id; /* device ID */
+ u8 rev;
+ u8 prog_intf;
+ u8 subclass;
+ u8 base_class;
+ u32 subsystem_id;
+ union win_slot_encoding win_slot;
+ u32 ser; /* serial number */
+} __packed;
+
+/**
+ * struct hv_msi_desc
+ * @vector: IDT entry
+ * @delivery_mode: As defined in Intel's Programmer's
+ * Reference Manual, Volume 3, Chapter 8.
+ * @vector_count: Number of contiguous entries in the
+ * Interrupt Descriptor Table that are
+ * occupied by this Message-Signaled
+ * Interrupt. For "MSI", as first defined
+ * in PCI 2.2, this can be between 1 and
+ * 32. For "MSI-X," as first defined in PCI
+ * 3.0, this must be 1, as each MSI-X table
+ * entry would have its own descriptor.
+ * @reserved: Empty space
+ * @cpu_mask: All the target virtual processors.
+ */
+struct hv_msi_desc {
+ u8 vector;
+ u8 delivery_mode;
+ u16 vector_count;
+ u32 reserved;
+ u64 cpu_mask;
+} __packed;
+
+/**
+ * struct tran_int_desc
+ * @reserved: unused, padding
+ * @vector_count: same as in hv_msi_desc
+ * @data: This is the "data payload" value that is
+ * written by the device when it generates
+ * a message-signaled interrupt, either MSI
+ * or MSI-X.
+ * @address: This is the address to which the data
+ * payload is written on interrupt
+ * generation.
+ */
+struct tran_int_desc {
+ u16 reserved;
+ u16 vector_count;
+ u32 data;
+ u64 address;
+} __packed;
+
+/*
+ * A generic message format for virtual PCI.
+ * Specific message formats are defined later in the file.
+ */
+
+struct pci_message {
+ u32 message_type;
+} __packed;
+
+struct pci_child_message {
+ u32 message_type;
+ union win_slot_encoding wslot;
+} __packed;
+
+struct pci_incoming_message {
+ struct vmpacket_descriptor hdr;
+ struct pci_message message_type;
+} __packed;
+
+struct pci_response {
+ struct vmpacket_descriptor hdr;
+ s32 status; /* negative values are failures */
+} __packed;
+
+struct pci_packet {
+ void (*completion_func)(void *context, struct pci_response *resp,
+ int resp_packet_size);
+ void *compl_ctxt;
+ struct pci_message message;
+};
+
+/*
+ * Specific message types supporting the PCI protocol.
+ */
+
+/*
+ * Version negotiation message. Sent from the guest to the host.
+ * The guest is free to try different versions until the host
+ * accepts the version.
+ *
+ * pci_version: The protocol version requested.
+ * is_last_attempt: If TRUE, this is the last version guest will request.
+ * reservedz: Reserved field, set to zero.
+ */
+
+struct pci_version_request {
+ struct pci_message message_type;
+ enum pci_message_type protocol_version;
+} __packed;
+
+/*
+ * Bus D0 Entry. This is sent from the guest to the host when the virtual
+ * bus (PCI Express port) is ready for action.
+ */
+
+struct pci_bus_d0_entry {
+ struct pci_message message_type;
+ u32 reserved;
+ u64 mmio_base;
+} __packed;
+
+struct pci_bus_relations {
+ struct pci_incoming_message incoming;
+ u32 device_count;
+ struct pci_function_description func[1];
+} __packed;
+
+struct pci_q_res_req_response {
+ struct vmpacket_descriptor hdr;
+ s32 status; /* negative values are failures */
+ u32 probed_bar[6];
+} __packed;
+
+struct pci_set_power {
+ struct pci_message message_type;
+ union win_slot_encoding wslot;
+ u32 power_state; /* In Windows terms */
+ u32 reserved;
+} __packed;
+
+struct pci_set_power_response {
+ struct vmpacket_descriptor hdr;
+ s32 status; /* negative values are failures */
+ union win_slot_encoding wslot;
+ u32 resultant_state; /* In Windows terms */
+ u32 reserved;
+} __packed;
+
+struct pci_resources_assigned {
+ struct pci_message message_type;
+ union win_slot_encoding wslot;
+ u8 memory_range[0x14][6]; /* not used here */
+ u32 msi_descriptors;
+ u32 reserved[4];
+} __packed;
+
+struct pci_create_interrupt {
+ struct pci_message message_type;
+ union win_slot_encoding wslot;
+ struct hv_msi_desc int_desc;
+} __packed;
+
+struct pci_create_int_response {
+ struct pci_response response;
+ u32 reserved;
+ struct tran_int_desc int_desc;
+} __packed;
+
+struct pci_delete_interrupt {
+ struct pci_message message_type;
+ union win_slot_encoding wslot;
+ struct tran_int_desc int_desc;
+} __packed;
+
+struct pci_dev_incoming {
+ struct pci_incoming_message incoming;
+ union win_slot_encoding wslot;
+} __packed;
+
+struct pci_eject_response {
+ u32 message_type;
+ union win_slot_encoding wslot;
+ u32 status;
+} __packed;
+
+static int pci_ring_size = (4 * PAGE_SIZE);
+
+/*
+ * Definitions or interrupt steering hypercall.
+ */
+#define HV_PARTITION_ID_SELF ((u64)-1)
+#define HVCALL_RETARGET_INTERRUPT 0x7e
+
+struct retarget_msi_interrupt {
+ u64 partition_id; /* use "self" */
+ u64 device_id;
+ u32 source; /* 1 for MSI(-X) */
+ u32 reserved1;
+ u32 address;
+ u32 data;
+ u64 reserved2;
+ u32 vector;
+ u32 flags;
+ u64 vp_mask;
+} __packed;
+
+/*
+ * Driver specific state.
+ */
+
+enum hv_pcibus_state {
+ hv_pcibus_init = 0,
+ hv_pcibus_probed,
+ hv_pcibus_installed,
+ hv_pcibus_maximum
+};
+
+struct hv_pcibus_device {
+ struct pci_sysdata sysdata;
+ enum hv_pcibus_state state;
+ atomic_t remove_lock;
+ struct hv_device *hdev;
+ resource_size_t low_mmio_space;
+ resource_size_t high_mmio_space;
+ struct resource *mem_config;
+ struct resource *low_mmio_res;
+ struct resource *high_mmio_res;
+ struct completion *survey_event;
+ struct completion remove_event;
+ struct pci_bus *pci_bus;
+ spinlock_t config_lock; /* Avoid two threads writing index page */
+ spinlock_t device_list_lock; /* Protect lists below */
+ void __iomem *cfg_addr;
+
+ struct semaphore enum_sem;
+ struct list_head resources_for_children;
+
+ struct list_head children;
+ struct list_head dr_list;
+ struct work_struct wrk;
+
+ struct msi_domain_info msi_info;
+ struct msi_controller msi_chip;
+ struct irq_domain *irq_domain;
+};
+
+/*
+ * Tracks "Device Relations" messages from the host, which must be both
+ * processed in order and deferred so that they don't run in the context
+ * of the incoming packet callback.
+ */
+struct hv_dr_work {
+ struct work_struct wrk;
+ struct hv_pcibus_device *bus;
+};
+
+struct hv_dr_state {
+ struct list_head list_entry;
+ u32 device_count;
+ struct pci_function_description func[1];
+};
+
+enum hv_pcichild_state {
+ hv_pcichild_init = 0,
+ hv_pcichild_requirements,
+ hv_pcichild_resourced,
+ hv_pcichild_ejecting,
+ hv_pcichild_maximum
+};
+
+enum hv_pcidev_ref_reason {
+ hv_pcidev_ref_invalid = 0,
+ hv_pcidev_ref_initial,
+ hv_pcidev_ref_by_slot,
+ hv_pcidev_ref_packet,
+ hv_pcidev_ref_pnp,
+ hv_pcidev_ref_childlist,
+ hv_pcidev_irqdata,
+ hv_pcidev_ref_max
+};
+
+struct hv_pci_dev {
+ /* List protected by pci_rescan_remove_lock */
+ struct list_head list_entry;
+ atomic_t refs;
+ enum hv_pcichild_state state;
+ struct pci_function_description desc;
+ bool reported_missing;
+ struct hv_pcibus_device *hbus;
+ struct work_struct wrk;
+
+ /*
+ * What would be observed if one wrote 0xFFFFFFFF to a BAR and then
+ * read it back, for each of the BAR offsets within config space.
+ */
+ u32 probed_bar[6];
+};
+
+struct hv_pci_compl {
+ struct completion host_event;
+ s32 completion_status;
+};
+
+/**
+ * hv_pci_generic_compl() - Invoked for a completion packet
+ * @context: Set up by the sender of the packet.
+ * @resp: The response packet
+ * @resp_packet_size: Size in bytes of the packet
+ *
+ * This function is used to trigger an event and report status
+ * for any message for which the completion packet contains a
+ * status and nothing else.
+ */
+static
+void
+hv_pci_generic_compl(void *context, struct pci_response *resp,
+ int resp_packet_size)
+{
+ struct hv_pci_compl *comp_pkt = context;
+
+ if (resp_packet_size >= offsetofend(struct pci_response, status))
+ comp_pkt->completion_status = resp->status;
+ complete(&comp_pkt->host_event);
+}
+
+static struct hv_pci_dev *get_pcichild_wslot(struct hv_pcibus_device *hbus,
+ u32 wslot);
+static void get_pcichild(struct hv_pci_dev *hv_pcidev,
+ enum hv_pcidev_ref_reason reason);
+static void put_pcichild(struct hv_pci_dev *hv_pcidev,
+ enum hv_pcidev_ref_reason reason);
+
+static void get_hvpcibus(struct hv_pcibus_device *hv_pcibus);
+static void put_hvpcibus(struct hv_pcibus_device *hv_pcibus);
+
+/**
+ * devfn_to_wslot() - Convert from Linux PCI slot to Windows
+ * @devfn: The Linux representation of PCI slot
+ *
+ * Windows uses a slightly different representation of PCI slot.
+ *
+ * Return: The Windows representation
+ */
+static u32 devfn_to_wslot(int devfn)
+{
+ union win_slot_encoding wslot;
+
+ wslot.slot = 0;
+ wslot.bits.func = PCI_SLOT(devfn) | (PCI_FUNC(devfn) << 5);
+
+ return wslot.slot;
+}
+
+/**
+ * wslot_to_devfn() - Convert from Windows PCI slot to Linux
+ * @wslot: The Windows representation of PCI slot
+ *
+ * Windows uses a slightly different representation of PCI slot.
+ *
+ * Return: The Linux representation
+ */
+static int wslot_to_devfn(u32 wslot)
+{
+ union win_slot_encoding slot_no;
+
+ slot_no.slot = wslot;
+ return PCI_DEVFN(0, slot_no.bits.func);
+}
+
+/*
+ * PCI Configuration Space for these root PCI buses is implemented as a pair
+ * of pages in memory-mapped I/O space. Writing to the first page chooses
+ * the PCI function being written or read. Once the first page has been
+ * written to, the following page maps in the entire configuration space of
+ * the function.
+ */
+
+/**
+ * _hv_pcifront_read_config() - Internal PCI config read
+ * @hpdev: The PCI driver's representation of the device
+ * @where: Offset within config space
+ * @size: Size of the transfer
+ * @val: Pointer to the buffer receiving the data
+ */
+static void _hv_pcifront_read_config(struct hv_pci_dev *hpdev, int where,
+ int size, u32 *val)
+{
+ unsigned long flags;
+ void __iomem *addr = hpdev->hbus->cfg_addr + CFG_PAGE_OFFSET + where;
+
+ /*
+ * If the attempt is to read the IDs or the ROM BAR, simulate that.
+ */
+ if (where + size <= PCI_COMMAND) {
+ memcpy(val, ((u8 *)&hpdev->desc.v_id) + where, size);
+ } else if (where >= PCI_CLASS_REVISION && where + size <=
+ PCI_CACHE_LINE_SIZE) {
+ memcpy(val, ((u8 *)&hpdev->desc.rev) + where -
+ PCI_CLASS_REVISION, size);
+ } else if (where >= PCI_SUBSYSTEM_VENDOR_ID && where + size <=
+ PCI_ROM_ADDRESS) {
+ memcpy(val, (u8 *)&hpdev->desc.subsystem_id + where -
+ PCI_SUBSYSTEM_VENDOR_ID, size);
+ } else if (where >= PCI_ROM_ADDRESS && where + size <=
+ PCI_CAPABILITY_LIST) {
+ /* ROM BARs are unimplemented */
+ *val = 0;
+ } else if (where >= PCI_INTERRUPT_LINE && where + size <=
+ PCI_INTERRUPT_PIN) {
+ /*
+ * Interrupt Line and Interrupt PIN are hard-wired to zero
+ * because this front-end only supports message-signaled
+ * interrupts.
+ */
+ *val = 0;
+ } else if (where + size <= CFG_PAGE_SIZE) {
+ spin_lock_irqsave(&hpdev->hbus->config_lock, flags);
+ /* Choose the function to be read. (See comment above) */
+ writel(hpdev->desc.win_slot.slot, hpdev->hbus->cfg_addr);
+ /* Read from that function's config space. */
+ switch (size) {
+ case 1:
+ *val = readb(addr);
+ break;
+ case 2:
+ *val = readw(addr);
+ break;
+ default:
+ *val = readl(addr);
+ break;
+ }
+ spin_unlock_irqrestore(&hpdev->hbus->config_lock, flags);
+ } else {
+ dev_err(&hpdev->hbus->hdev->device,
+ "Attempt to read beyond a function's config space.\n");
+ }
+}
+
+/**
+ * _hv_pcifront_write_config() - Internal PCI config write
+ * @hpdev: The PCI driver's representation of the device
+ * @where: Offset within config space
+ * @size: Size of the transfer
+ * @val: The data being transferred
+ */
+static void _hv_pcifront_write_config(struct hv_pci_dev *hpdev, int where,
+ int size, u32 val)
+{
+ unsigned long flags;
+ void __iomem *addr = hpdev->hbus->cfg_addr + CFG_PAGE_OFFSET + where;
+
+ if (where >= PCI_SUBSYSTEM_VENDOR_ID &&
+ where + size <= PCI_CAPABILITY_LIST) {
+ /* SSIDs and ROM BARs are read-only */
+ } else if (where >= PCI_COMMAND && where + size <= CFG_PAGE_SIZE) {
+ spin_lock_irqsave(&hpdev->hbus->config_lock, flags);
+ /* Choose the function to be written. (See comment above) */
+ writel(hpdev->desc.win_slot.slot, hpdev->hbus->cfg_addr);
+ /* Write to that function's config space. */
+ switch (size) {
+ case 1:
+ writeb(val, addr);
+ break;
+ case 2:
+ writew(val, addr);
+ break;
+ default:
+ writel(val, addr);
+ break;
+ }
+ spin_unlock_irqrestore(&hpdev->hbus->config_lock, flags);
+ } else {
+ dev_err(&hpdev->hbus->hdev->device,
+ "Attempt to write beyond a function's config space.\n");
+ }
+}
+
+/**
+ * hv_pcifront_read_config() - Read configuration space
+ * @bus: PCI Bus structure
+ * @devfn: Device/function
+ * @where: Offset from base
+ * @size: Byte/word/dword
+ * @val: Value to be read
+ *
+ * Return: PCIBIOS_SUCCESSFUL on success
+ * PCIBIOS_DEVICE_NOT_FOUND on failure
+ */
+static int hv_pcifront_read_config(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 *val)
+{
+ struct hv_pcibus_device *hbus =
+ container_of(bus->sysdata, struct hv_pcibus_device, sysdata);
+ struct hv_pci_dev *hpdev;
+
+ hpdev = get_pcichild_wslot(hbus, devfn_to_wslot(devfn));
+ if (!hpdev)
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
+ _hv_pcifront_read_config(hpdev, where, size, val);
+
+ put_pcichild(hpdev, hv_pcidev_ref_by_slot);
+ return PCIBIOS_SUCCESSFUL;
+}
+
+/**
+ * hv_pcifront_write_config() - Write configuration space
+ * @bus: PCI Bus structure
+ * @devfn: Device/function
+ * @where: Offset from base
+ * @size: Byte/word/dword
+ * @val: Value to be written to device
+ *
+ * Return: PCIBIOS_SUCCESSFUL on success
+ * PCIBIOS_DEVICE_NOT_FOUND on failure
+ */
+static int hv_pcifront_write_config(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 val)
+{
+ struct hv_pcibus_device *hbus =
+ container_of(bus->sysdata, struct hv_pcibus_device, sysdata);
+ struct hv_pci_dev *hpdev;
+
+ hpdev = get_pcichild_wslot(hbus, devfn_to_wslot(devfn));
+ if (!hpdev)
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
+ _hv_pcifront_write_config(hpdev, where, size, val);
+
+ put_pcichild(hpdev, hv_pcidev_ref_by_slot);
+ return PCIBIOS_SUCCESSFUL;
+}
+
+/* PCIe operations */
+static struct pci_ops hv_pcifront_ops = {
+ .read = hv_pcifront_read_config,
+ .write = hv_pcifront_write_config,
+};
+
+/* Interrupt management hooks */
+static void hv_int_desc_free(struct hv_pci_dev *hpdev,
+ struct tran_int_desc *int_desc)
+{
+ struct pci_delete_interrupt *int_pkt;
+ struct {
+ struct pci_packet pkt;
+ u8 buffer[sizeof(struct pci_delete_interrupt) -
+ sizeof(struct pci_message)];
+ } ctxt;
+
+ memset(&ctxt, 0, sizeof(ctxt));
+ int_pkt = (struct pci_delete_interrupt *)&ctxt.pkt.message;
+ int_pkt->message_type.message_type =
+ PCI_DELETE_INTERRUPT_MESSAGE;
+ int_pkt->wslot.slot = hpdev->desc.win_slot.slot;
+ int_pkt->int_desc = *int_desc;
+ vmbus_sendpacket(hpdev->hbus->hdev->channel, int_pkt, sizeof(*int_pkt),
+ (unsigned long)&ctxt.pkt, VM_PKT_DATA_INBAND, 0);
+ kfree(int_desc);
+}
+
+/**
+ * hv_msi_free() - Free the MSI.
+ * @domain: The interrupt domain pointer
+ * @info: Extra MSI-related context
+ * @irq: Identifies the IRQ.
+ *
+ * The Hyper-V parent partition and hypervisor are tracking the
+ * messages that are in use, keeping the interrupt redirection
+ * table up to date. This callback sends a message that frees
+ * the IRT entry and related tracking nonsense.
+ */
+static void hv_msi_free(struct irq_domain *domain, struct msi_domain_info *info,
+ unsigned int irq)
+{
+ struct hv_pcibus_device *hbus;
+ struct hv_pci_dev *hpdev;
+ struct pci_dev *pdev;
+ struct tran_int_desc *int_desc;
+ struct irq_data *irq_data = irq_domain_get_irq_data(domain, irq);
+ struct msi_desc *msi = irq_data_get_msi_desc(irq_data);
+
+ pdev = msi_desc_to_pci_dev(msi);
+ hbus = info->data;
+ hpdev = get_pcichild_wslot(hbus, devfn_to_wslot(pdev->devfn));
+ if (!hpdev)
+ return;
+
+ int_desc = irq_data_get_irq_chip_data(irq_data);
+ if (int_desc) {
+ irq_data->chip_data = NULL;
+ hv_int_desc_free(hpdev, int_desc);
+ }
+
+ put_pcichild(hpdev, hv_pcidev_ref_by_slot);
+}
+
+static int hv_set_affinity(struct irq_data *data, const struct cpumask *dest,
+ bool force)
+{
+ struct irq_data *parent = data->parent_data;
+
+ return parent->chip->irq_set_affinity(parent, dest, force);
+}
+
+void hv_irq_mask(struct irq_data *data)
+{
+ pci_msi_mask_irq(data);
+}
+
+/**
+ * hv_irq_unmask() - "Unmask" the IRQ by setting its current
+ * affinity.
+ * @data: Describes the IRQ
+ *
+ * Build new a destination for the MSI and make a hypercall to
+ * update the Interrupt Redirection Table. "Device Logical ID"
+ * is built out of this PCI bus's instance GUID and the function
+ * number of the device.
+ */
+void hv_irq_unmask(struct irq_data *data)
+{
+ struct msi_desc *msi_desc = irq_data_get_msi_desc(data);
+ struct irq_cfg *cfg = irqd_cfg(data);
+ struct retarget_msi_interrupt params;
+ struct hv_pcibus_device *hbus;
+ struct cpumask *dest;
+ struct pci_bus *pbus;
+ struct pci_dev *pdev;
+ int cpu;
+
+ dest = irq_data_get_affinity_mask(data);
+ pdev = msi_desc_to_pci_dev(msi_desc);
+ pbus = pdev->bus;
+ hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata);
+
+ memset(¶ms, 0, sizeof(params));
+ params.partition_id = HV_PARTITION_ID_SELF;
+ params.source = 1; /* MSI(-X) */
+ params.address = msi_desc->msg.address_lo;
+ params.data = msi_desc->msg.data;
+ params.device_id = (hbus->hdev->dev_instance.b[5] << 24) |
+ (hbus->hdev->dev_instance.b[4] << 16) |
+ (hbus->hdev->dev_instance.b[7] << 8) |
+ (hbus->hdev->dev_instance.b[6] & 0xf8) |
+ PCI_FUNC(pdev->devfn);
+ params.vector = cfg->vector;
+
+ for_each_cpu_and(cpu, dest, cpu_online_mask)
+ params.vp_mask |= (1ULL << vmbus_cpu_number_to_vp_number(cpu));
+
+ hv_do_hypercall(HVCALL_RETARGET_INTERRUPT, ¶ms, NULL);
+
+ pci_msi_unmask_irq(data);
+}
+
+struct compose_comp_ctxt {
+ struct hv_pci_compl comp_pkt;
+ struct tran_int_desc int_desc;
+};
+
+static void hv_pci_compose_compl(void *context, struct pci_response *resp,
+ int resp_packet_size)
+{
+ struct compose_comp_ctxt *comp_pkt = context;
+ struct pci_create_int_response *int_resp =
+ (struct pci_create_int_response *)resp;
+
+ comp_pkt->comp_pkt.completion_status = resp->status;
+ comp_pkt->int_desc = int_resp->int_desc;
+ complete(&comp_pkt->comp_pkt.host_event);
+}
+
+/**
+ * hv_compose_msi_msg() - Supplies a valid MSI address/data
+ * @data: Everything about this MSI
+ * @msg: Buffer that is filled in by this function
+ *
+ * This function unpacks the IRQ looking for target CPU set, IDT
+ * vector and mode and sends a message to the parent partition
+ * asking for a mapping for that tuple in this partition. The
+ * response supplies a data value and address to which that data
+ * should be written to trigger that interrupt.
+ */
+static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+ struct irq_cfg *cfg = irqd_cfg(data);
+ struct hv_pcibus_device *hbus;
+ struct hv_pci_dev *hpdev;
+ struct pci_bus *pbus;
+ struct pci_dev *pdev;
+ struct pci_create_interrupt *int_pkt;
+ struct compose_comp_ctxt comp;
+ struct tran_int_desc *int_desc;
+ struct cpumask *affinity;
+ struct {
+ struct pci_packet pkt;
+ u8 buffer[sizeof(struct pci_create_interrupt) -
+ sizeof(struct pci_message)];
+ } ctxt;
+ int cpu;
+ int ret;
+
+ pdev = msi_desc_to_pci_dev(irq_data_get_msi_desc(data));
+ pbus = pdev->bus;
+ hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata);
+ hpdev = get_pcichild_wslot(hbus, devfn_to_wslot(pdev->devfn));
+ if (!hpdev)
+ goto return_null_message;
+
+ /* Free any previous message that might have already been composed. */
+ if (data->chip_data) {
+ int_desc = data->chip_data;
+ data->chip_data = NULL;
+ hv_int_desc_free(hpdev, int_desc);
+ }
+
+ int_desc = kzalloc(sizeof(*int_desc), GFP_KERNEL);
+ if (!int_desc)
+ goto drop_reference;
+
+ memset(&ctxt, 0, sizeof(ctxt));
+ init_completion(&comp.comp_pkt.host_event);
+ ctxt.pkt.completion_func = hv_pci_compose_compl;
+ ctxt.pkt.compl_ctxt = ∁
+ int_pkt = (struct pci_create_interrupt *)&ctxt.pkt.message;
+ int_pkt->message_type.message_type = PCI_CREATE_INTERRUPT_MESSAGE;
+ int_pkt->wslot.slot = hpdev->desc.win_slot.slot;
+ int_pkt->int_desc.vector = cfg->vector;
+ int_pkt->int_desc.vector_count = 1;
+ int_pkt->int_desc.delivery_mode =
+ (apic->irq_delivery_mode == dest_LowestPrio) ? 1 : 0;
+
+ /*
+ * This bit doesn't have to work on machines with more than 64
+ * processors because Hyper-V only supports 64 in a guest.
+ */
+ affinity = irq_data_get_affinity_mask(data);
+ for_each_cpu_and(cpu, affinity, cpu_online_mask) {
+ int_pkt->int_desc.cpu_mask |=
+ (1ULL << vmbus_cpu_number_to_vp_number(cpu));
+ }
+
+ ret = vmbus_sendpacket(hpdev->hbus->hdev->channel, int_pkt,
+ sizeof(*int_pkt), (unsigned long)&ctxt.pkt,
+ VM_PKT_DATA_INBAND,
+ VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ if (!ret)
+ wait_for_completion(&comp.comp_pkt.host_event);
+
+ if (comp.comp_pkt.completion_status < 0) {
+ dev_err(&hbus->hdev->device,
+ "Request for interrupt failed: 0x%x",
+ comp.comp_pkt.completion_status);
+ goto free_int_desc;
+ }
+
+ /*
+ * Record the assignment so that this can be unwound later. Using
+ * irq_set_chip_data() here would be appropriate, but the lock it takes
+ * is already held.
+ */
+ *int_desc = comp.int_desc;
+ data->chip_data = int_desc;
+
+ /* Pass up the result. */
+ msg->address_hi = comp.int_desc.address >> 32;
+ msg->address_lo = comp.int_desc.address & 0xffffffff;
+ msg->data = comp.int_desc.data;
+
+ put_pcichild(hpdev, hv_pcidev_ref_by_slot);
+ return;
+
+free_int_desc:
+ kfree(int_desc);
+drop_reference:
+ put_pcichild(hpdev, hv_pcidev_ref_by_slot);
+return_null_message:
+ msg->address_hi = 0;
+ msg->address_lo = 0;
+ msg->data = 0;
+}
+
+/* HW Interrupt Chip Descriptor */
+static struct irq_chip hv_msi_irq_chip = {
+ .name = "Hyper-V PCIe MSI",
+ .irq_compose_msi_msg = hv_compose_msi_msg,
+ .irq_set_affinity = hv_set_affinity,
+ .irq_ack = irq_chip_ack_parent,
+ .irq_mask = hv_irq_mask,
+ .irq_unmask = hv_irq_unmask,
+};
+
+static irq_hw_number_t hv_msi_domain_ops_get_hwirq(struct msi_domain_info *info,
+ msi_alloc_info_t *arg)
+{
+ return arg->msi_hwirq;
+}
+
+static struct msi_domain_ops hv_msi_ops = {
+ .get_hwirq = hv_msi_domain_ops_get_hwirq,
+ .msi_prepare = pci_msi_prepare,
+ .set_desc = pci_msi_set_desc,
+ .msi_free = hv_msi_free,
+};
+
+/**
+ * hv_pcie_init_irq_domain() - Initialize IRQ domain
+ * @hbus: The root PCI bus
+ *
+ * This function creates an IRQ domain which will be used for
+ * interrupts from devices that have been passed through. These
+ * devices only support MSI and MSI-X, not line-based interrupts
+ * or simulations of line-based interrupts through PCIe's
+ * fabric-layer messages. Because interrupts are remapped, we
+ * can support multi-message MSI here.
+ *
+ * Return: '0' on success and error value on failure
+ */
+static int hv_pcie_init_irq_domain(struct hv_pcibus_device *hbus)
+{
+ hbus->msi_info.chip = &hv_msi_irq_chip;
+ hbus->msi_info.ops = &hv_msi_ops;
+ hbus->msi_info.flags = (MSI_FLAG_USE_DEF_DOM_OPS |
+ MSI_FLAG_USE_DEF_CHIP_OPS | MSI_FLAG_MULTI_PCI_MSI |
+ MSI_FLAG_PCI_MSIX);
+ hbus->msi_info.handler = handle_edge_irq;
+ hbus->msi_info.handler_name = "edge";
+ hbus->msi_info.data = hbus;
+ hbus->irq_domain = pci_msi_create_irq_domain(hbus->sysdata.fwnode,
+ &hbus->msi_info,
+ x86_vector_domain);
+ if (!hbus->irq_domain) {
+ dev_err(&hbus->hdev->device,
+ "Failed to build an MSI IRQ domain\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+/**
+ * get_bar_size() - Get the address space consumed by a BAR
+ * @bar_val: Value that a BAR returned after -1 was written
+ * to it.
+ *
+ * This function returns the size of the BAR, rounded up to 1
+ * page. It has to be rounded up because the hypervisor's page
+ * table entry that maps the BAR into the VM can't specify an
+ * offset within a page. The invariant is that the hypervisor
+ * must place any BARs of smaller than page length at the
+ * beginning of a page.
+ *
+ * Return: Size in bytes of the consumed MMIO space.
+ */
+static u64 get_bar_size(u64 bar_val)
+{
+ return round_up((1 + ~(bar_val & PCI_BASE_ADDRESS_MEM_MASK)),
+ PAGE_SIZE);
+}
+
+/**
+ * survey_child_resources() - Total all MMIO requirements
+ * @hbus: Root PCI bus, as understood by this driver
+ */
+static void survey_child_resources(struct hv_pcibus_device *hbus)
+{
+ struct list_head *iter;
+ struct hv_pci_dev *hpdev;
+ resource_size_t bar_size = 0;
+ unsigned long flags;
+ struct completion *event;
+ u64 bar_val;
+ int i;
+
+ /* If nobody is waiting on the answer, don't compute it. */
+ event = xchg(&hbus->survey_event, NULL);
+ if (!event)
+ return;
+
+ /* If the answer has already been computed, go with it. */
+ if (hbus->low_mmio_space || hbus->high_mmio_space) {
+ complete(event);
+ return;
+ }
+
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
+
+ /*
+ * Due to an interesting quirk of the PCI spec, all memory regions
+ * for a child device are a power of 2 in size and aligned in memory,
+ * so it's sufficient to just add them up without tracking alignment.
+ */
+ list_for_each(iter, &hbus->children) {
+ hpdev = container_of(iter, struct hv_pci_dev, list_entry);
+ for (i = 0; i < 6; i++) {
+ if (hpdev->probed_bar[i] & PCI_BASE_ADDRESS_SPACE_IO)
+ dev_err(&hbus->hdev->device,
+ "There's an I/O BAR in this list!\n");
+
+ if (hpdev->probed_bar[i] != 0) {
+ /*
+ * A probed BAR has all the upper bits set that
+ * can be changed.
+ */
+
+ bar_val = hpdev->probed_bar[i];
+ if (bar_val & PCI_BASE_ADDRESS_MEM_TYPE_64)
+ bar_val |=
+ ((u64)hpdev->probed_bar[++i] << 32);
+ else
+ bar_val |= 0xffffffff00000000ULL;
+
+ bar_size = get_bar_size(bar_val);
+
+ if (bar_val & PCI_BASE_ADDRESS_MEM_TYPE_64)
+ hbus->high_mmio_space += bar_size;
+ else
+ hbus->low_mmio_space += bar_size;
+ }
+ }
+ }
+
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);
+ complete(event);
+}
+
+/**
+ * prepopulate_bars() - Fill in BARs with defaults
+ * @hbus: Root PCI bus, as understood by this driver
+ *
+ * The core PCI driver code seems much, much happier if the BARs
+ * for a device have values upon first scan. So fill them in.
+ * The algorithm below works down from large sizes to small,
+ * attempting to pack the assignments optimally. The assumption,
+ * enforced in other parts of the code, is that the beginning of
+ * the memory-mapped I/O space will be aligned on the largest
+ * BAR size.
+ */
+static void prepopulate_bars(struct hv_pcibus_device *hbus)
+{
+ resource_size_t high_size = 0;
+ resource_size_t low_size = 0;
+ resource_size_t high_base = 0;
+ resource_size_t low_base = 0;
+ resource_size_t bar_size;
+ struct hv_pci_dev *hpdev;
+ struct list_head *iter;
+ unsigned long flags;
+ u64 bar_val;
+ u32 command;
+ bool high;
+ int i;
+
+ if (hbus->low_mmio_space) {
+ low_size = 1ULL << (63 - __builtin_clzll(hbus->low_mmio_space));
+ low_base = hbus->low_mmio_res->start;
+ }
+
+ if (hbus->high_mmio_space) {
+ high_size = 1ULL <<
+ (63 - __builtin_clzll(hbus->high_mmio_space));
+ high_base = hbus->high_mmio_res->start;
+ }
+
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
+
+ /* Pick addresses for the BARs. */
+ do {
+ list_for_each(iter, &hbus->children) {
+ hpdev = container_of(iter, struct hv_pci_dev,
+ list_entry);
+ for (i = 0; i < 6; i++) {
+ bar_val = hpdev->probed_bar[i];
+ if (bar_val == 0)
+ continue;
+ high = bar_val & PCI_BASE_ADDRESS_MEM_TYPE_64;
+ if (high) {
+ bar_val |=
+ ((u64)hpdev->probed_bar[i + 1]
+ << 32);
+ } else {
+ bar_val |= 0xffffffffULL << 32;
+ }
+ bar_size = get_bar_size(bar_val);
+ if (high) {
+ if (high_size != bar_size) {
+ i++;
+ continue;
+ }
+ _hv_pcifront_write_config(hpdev,
+ PCI_BASE_ADDRESS_0 + (4 * i),
+ 4,
+ (u32)(high_base & 0xffffff00));
+ i++;
+ _hv_pcifront_write_config(hpdev,
+ PCI_BASE_ADDRESS_0 + (4 * i),
+ 4, (u32)(high_base >> 32));
+ high_base += bar_size;
+ } else {
+ if (low_size != bar_size)
+ continue;
+ _hv_pcifront_write_config(hpdev,
+ PCI_BASE_ADDRESS_0 + (4 * i),
+ 4,
+ (u32)(low_base & 0xffffff00));
+ low_base += bar_size;
+ }
+ }
+ if (high_size <= 1 && low_size <= 1) {
+ /* Set the memory enable bit. */
+ _hv_pcifront_read_config(hpdev, PCI_COMMAND, 2,
+ &command);
+ command |= PCI_COMMAND_MEMORY;
+ _hv_pcifront_write_config(hpdev, PCI_COMMAND, 2,
+ command);
+ break;
+ }
+ }
+
+ high_size >>= 1;
+ low_size >>= 1;
+ } while (high_size || low_size);
+
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);
+}
+
+/**
+ * create_root_hv_pci_bus() - Expose a new root PCI bus
+ * @hbus: Root PCI bus, as understood by this driver
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int create_root_hv_pci_bus(struct hv_pcibus_device *hbus)
+{
+ /* Register the device */
+ hbus->pci_bus = pci_create_root_bus(&hbus->hdev->device,
+ 0, /* bus number is always zero */
+ &hv_pcifront_ops,
+ &hbus->sysdata,
+ &hbus->resources_for_children);
+ if (!hbus->pci_bus)
+ return -ENODEV;
+
+ hbus->pci_bus->msi = &hbus->msi_chip;
+ hbus->pci_bus->msi->dev = &hbus->hdev->device;
+
+ pci_scan_child_bus(hbus->pci_bus);
+ pci_bus_assign_resources(hbus->pci_bus);
+ pci_bus_add_devices(hbus->pci_bus);
+ hbus->state = hv_pcibus_installed;
+ return 0;
+}
+
+struct q_res_req_compl {
+ struct completion host_event;
+ struct hv_pci_dev *hpdev;
+};
+
+/**
+ * q_resource_requirements() - Query Resource Requirements
+ * @context: The completion context.
+ * @resp: The response that came from the host.
+ * @resp_packet_size: The size in bytes of resp.
+ *
+ * This function is invoked on completion of a Query Resource
+ * Requirements packet.
+ */
+static void q_resource_requirements(void *context, struct pci_response *resp,
+ int resp_packet_size)
+{
+ struct q_res_req_compl *completion = context;
+ struct pci_q_res_req_response *q_res_req =
+ (struct pci_q_res_req_response *)resp;
+ int i;
+
+ if (resp->status < 0) {
+ dev_err(&completion->hpdev->hbus->hdev->device,
+ "query resource requirements failed: %x\n",
+ resp->status);
+ } else {
+ for (i = 0; i < 6; i++) {
+ completion->hpdev->probed_bar[i] =
+ q_res_req->probed_bar[i];
+ }
+ }
+
+ complete(&completion->host_event);
+}
+
+static void get_pcichild(struct hv_pci_dev *hpdev,
+ enum hv_pcidev_ref_reason reason)
+{
+ atomic_inc(&hpdev->refs);
+}
+
+static void put_pcichild(struct hv_pci_dev *hpdev,
+ enum hv_pcidev_ref_reason reason)
+{
+ if (atomic_dec_and_test(&hpdev->refs))
+ kfree(hpdev);
+}
+
+/**
+ * new_pcichild_device() - Create a new child device
+ * @hbus: The internal struct tracking this root PCI bus.
+ * @desc: The information supplied so far from the host
+ * about the device.
+ *
+ * This function creates the tracking structure for a new child
+ * device and kicks off the process of figuring out what it is.
+ *
+ * Return: Pointer to the new tracking struct
+ */
+static struct hv_pci_dev *new_pcichild_device(struct hv_pcibus_device *hbus,
+ struct pci_function_description *desc)
+{
+ struct hv_pci_dev *hpdev;
+ struct pci_child_message *res_req;
+ struct q_res_req_compl comp_pkt;
+ union {
+ struct pci_packet init_packet;
+ u8 buffer[0x100];
+ } pkt;
+ unsigned long flags;
+ int ret;
+
+ hpdev = kzalloc(sizeof(*hpdev), GFP_ATOMIC);
+ if (!hpdev)
+ return NULL;
+
+ hpdev->hbus = hbus;
+
+ memset(&pkt, 0, sizeof(pkt));
+ init_completion(&comp_pkt.host_event);
+ comp_pkt.hpdev = hpdev;
+ pkt.init_packet.compl_ctxt = &comp_pkt;
+ pkt.init_packet.completion_func = q_resource_requirements;
+ res_req = (struct pci_child_message *)&pkt.init_packet.message;
+ res_req->message_type = PCI_QUERY_RESOURCE_REQUIREMENTS;
+ res_req->wslot.slot = desc->win_slot.slot;
+
+ ret = vmbus_sendpacket(hbus->hdev->channel, res_req,
+ sizeof(struct pci_child_message),
+ (unsigned long)&pkt.init_packet,
+ VM_PKT_DATA_INBAND,
+ VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ if (ret)
+ goto error;
+
+ wait_for_completion(&comp_pkt.host_event);
+
+ hpdev->desc = *desc;
+ get_pcichild(hpdev, hv_pcidev_ref_initial);
+ get_pcichild(hpdev, hv_pcidev_ref_childlist);
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
+ list_add_tail(&hpdev->list_entry, &hbus->children);
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);
+ return hpdev;
+
+error:
+ kfree(hpdev);
+ return NULL;
+}
+
+/**
+ * get_pcichild_wslot() - Find device from slot
+ * @hbus: Root PCI bus, as understood by this driver
+ * @wslot: Location on the bus
+ *
+ * This function looks up a PCI device and returns the internal
+ * representation of it. It acquires a reference on it, so that
+ * the device won't be deleted while somebody is using it. The
+ * caller is responsible for calling put_pcichild() to release
+ * this reference.
+ *
+ * Return: Internal representation of a PCI device
+ */
+static struct hv_pci_dev *get_pcichild_wslot(struct hv_pcibus_device *hbus,
+ u32 wslot)
+{
+ unsigned long flags;
+ struct hv_pci_dev *iter, *hpdev = NULL;
+
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
+ list_for_each_entry(iter, &hbus->children, list_entry) {
+ if (iter->desc.win_slot.slot == wslot) {
+ hpdev = iter;
+ get_pcichild(hpdev, hv_pcidev_ref_by_slot);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);
+
+ return hpdev;
+}
+
+/**
+ * pci_devices_present_work() - Handle new list of child devices
+ * @work: Work struct embedded in struct hv_dr_work
+ *
+ * "Bus Relations" is the Windows term for "children of this
+ * bus." The terminology is preserved here for people trying to
+ * debug the interaction between Hyper-V and Linux. This
+ * function is called when the parent partition reports a list
+ * of functions that should be observed under this PCI Express
+ * port (bus).
+ *
+ * This function updates the list, and must tolerate being
+ * called multiple times with the same information. The typical
+ * number of child devices is one, with very atypical cases
+ * involving three or four, so the algorithms used here can be
+ * simple and inefficient.
+ *
+ * It must also treat the omission of a previously observed device as
+ * notification that the device no longer exists.
+ *
+ * Note that this function is a work item, and it may not be
+ * invoked in the order that it was queued. Back to back
+ * updates of the list of present devices may involve queuing
+ * multiple work items, and this one may run before ones that
+ * were sent later. As such, this function only does something
+ * if is the last one in the queue.
+ */
+static void pci_devices_present_work(struct work_struct *work)
+{
+ u32 child_no;
+ bool found;
+ struct list_head *iter;
+ struct pci_function_description *new_desc;
+ struct hv_pci_dev *hpdev;
+ struct hv_pcibus_device *hbus;
+ struct list_head removed;
+ struct hv_dr_work *dr_wrk;
+ struct hv_dr_state *dr = NULL;
+ unsigned long flags;
+
+ dr_wrk = container_of(work, struct hv_dr_work, wrk);
+ hbus = dr_wrk->bus;
+ kfree(dr_wrk);
+
+ INIT_LIST_HEAD(&removed);
+
+ if (down_interruptible(&hbus->enum_sem)) {
+ put_hvpcibus(hbus);
+ return;
+ }
+
+ /* Pull this off the queue and process it if it was the last one. */
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
+ while (!list_empty(&hbus->dr_list)) {
+ dr = list_first_entry(&hbus->dr_list, struct hv_dr_state,
+ list_entry);
+ list_del(&dr->list_entry);
+
+ /* Throw this away if the list still has stuff in it. */
+ if (!list_empty(&hbus->dr_list)) {
+ kfree(dr);
+ continue;
+ }
+ }
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);
+
+ if (!dr) {
+ up(&hbus->enum_sem);
+ put_hvpcibus(hbus);
+ return;
+ }
+
+ /* First, mark all existing children as reported missing. */
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
+ list_for_each(iter, &hbus->children) {
+ hpdev = container_of(iter, struct hv_pci_dev,
+ list_entry);
+ hpdev->reported_missing = true;
+ }
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);
+
+ /* Next, add back any reported devices. */
+ for (child_no = 0; child_no < dr->device_count; child_no++) {
+ found = false;
+ new_desc = &dr->func[child_no];
+
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
+ list_for_each(iter, &hbus->children) {
+ hpdev = container_of(iter, struct hv_pci_dev,
+ list_entry);
+ if ((hpdev->desc.win_slot.slot ==
+ new_desc->win_slot.slot) &&
+ (hpdev->desc.v_id == new_desc->v_id) &&
+ (hpdev->desc.d_id == new_desc->d_id) &&
+ (hpdev->desc.ser == new_desc->ser)) {
+ hpdev->reported_missing = false;
+ found = true;
+ }
+ }
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);
+
+ if (!found) {
+ hpdev = new_pcichild_device(hbus, new_desc);
+ if (!hpdev)
+ dev_err(&hbus->hdev->device,
+ "couldn't record a child device.\n");
+ }
+ }
+
+ /* Move missing children to a list on the stack. */
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
+ do {
+ found = false;
+ list_for_each(iter, &hbus->children) {
+ hpdev = container_of(iter, struct hv_pci_dev,
+ list_entry);
+ if (hpdev->reported_missing) {
+ found = true;
+ put_pcichild(hpdev, hv_pcidev_ref_childlist);
+ list_del(&hpdev->list_entry);
+ list_add_tail(&hpdev->list_entry, &removed);
+ break;
+ }
+ }
+ } while (found);
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);
+
+ /* Delete everything that should no longer exist. */
+ while (!list_empty(&removed)) {
+ hpdev = list_first_entry(&removed, struct hv_pci_dev,
+ list_entry);
+ list_del(&hpdev->list_entry);
+ put_pcichild(hpdev, hv_pcidev_ref_initial);
+ }
+
+ /* Tell the core to rescan bus because there may have been changes. */
+ if (hbus->state == hv_pcibus_installed) {
+ pci_lock_rescan_remove();
+ pci_scan_child_bus(hbus->pci_bus);
+ pci_unlock_rescan_remove();
+ } else {
+ survey_child_resources(hbus);
+ }
+
+ up(&hbus->enum_sem);
+ put_hvpcibus(hbus);
+ kfree(dr);
+}
+
+/**
+ * hv_pci_devices_present() - Handles list of new children
+ * @hbus: Root PCI bus, as understood by this driver
+ * @relations: Packet from host listing children
+ *
+ * This function is invoked whenever a new list of devices for
+ * this bus appears.
+ */
+static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
+ struct pci_bus_relations *relations)
+{
+ struct hv_dr_state *dr;
+ struct hv_dr_work *dr_wrk;
+ unsigned long flags;
+
+ dr_wrk = kzalloc(sizeof(*dr_wrk), GFP_NOWAIT);
+ if (!dr_wrk)
+ return;
+
+ dr = kzalloc(offsetof(struct hv_dr_state, func) +
+ (sizeof(struct pci_function_description) *
+ (relations->device_count)), GFP_NOWAIT);
+ if (!dr) {
+ kfree(dr_wrk);
+ return;
+ }
+
+ INIT_WORK(&dr_wrk->wrk, pci_devices_present_work);
+ dr_wrk->bus = hbus;
+ dr->device_count = relations->device_count;
+ if (dr->device_count != 0) {
+ memcpy(dr->func, relations->func,
+ sizeof(struct pci_function_description) *
+ dr->device_count);
+ }
+
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
+ list_add_tail(&dr->list_entry, &hbus->dr_list);
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);
+
+ get_hvpcibus(hbus);
+ schedule_work(&dr_wrk->wrk);
+}
+
+/**
+ * hv_eject_device_work() - Asynchronously handles ejection
+ * @work: Work struct embedded in internal device struct
+ *
+ * This function handles ejecting a device. Windows will
+ * attempt to gracefully eject a device, waiting 60 seconds to
+ * hear back from the guest OS that this completed successfully.
+ * If this timer expires, the device will be forcibly removed.
+ */
+static void hv_eject_device_work(struct work_struct *work)
+{
+ struct pci_eject_response *ejct_pkt;
+ struct hv_pci_dev *hpdev;
+ struct pci_dev *pdev;
+ unsigned long flags;
+ int wslot;
+ struct {
+ struct pci_packet pkt;
+ u8 buffer[sizeof(struct pci_eject_response) -
+ sizeof(struct pci_message)];
+ } ctxt;
+
+ hpdev = container_of(work, struct hv_pci_dev, wrk);
+
+ if (hpdev->state != hv_pcichild_ejecting) {
+ put_pcichild(hpdev, hv_pcidev_ref_pnp);
+ return;
+ }
+
+ /*
+ * Ejection can come before or after the PCI bus has been set up, so
+ * attempt to find it and tear down the bus state, if it exists. This
+ * must be done without constructs like pci_domain_nr(hbus->pci_bus)
+ * because hbus->pci_bus may not exist yet.
+ */
+ wslot = wslot_to_devfn(hpdev->desc.win_slot.slot);
+ pdev = pci_get_domain_bus_and_slot(hpdev->hbus->sysdata.domain, 0,
+ wslot);
+ if (pdev) {
+ pci_stop_and_remove_bus_device(pdev);
+ pci_dev_put(pdev);
+ }
+
+ memset(&ctxt, 0, sizeof(ctxt));
+ ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message;
+ ejct_pkt->message_type = PCI_EJECTION_COMPLETE;
+ ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot;
+ vmbus_sendpacket(hpdev->hbus->hdev->channel, ejct_pkt,
+ sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt,
+ VM_PKT_DATA_INBAND, 0);
+
+ spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags);
+ list_del(&hpdev->list_entry);
+ spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags);
+
+ put_pcichild(hpdev, hv_pcidev_ref_childlist);
+ put_pcichild(hpdev, hv_pcidev_ref_pnp);
+ put_hvpcibus(hpdev->hbus);
+}
+
+/**
+ * hv_pci_eject_device() - Handles device ejection
+ * @hpdev: Internal device tracking struct
+ *
+ * This function is invoked when an ejection packet arrives. It
+ * just schedules work so that we don't re-enter the packet
+ * delivery code handling the ejection.
+ */
+static void hv_pci_eject_device(struct hv_pci_dev *hpdev)
+{
+ hpdev->state = hv_pcichild_ejecting;
+ get_pcichild(hpdev, hv_pcidev_ref_pnp);
+ INIT_WORK(&hpdev->wrk, hv_eject_device_work);
+ get_hvpcibus(hpdev->hbus);
+ schedule_work(&hpdev->wrk);
+}
+
+/**
+ * hv_pci_onchannelcallback() - Handles incoming packets
+ * @context: Internal bus tracking struct
+ *
+ * This function is invoked whenever the host sends a packet to
+ * this channel (which is private to this root PCI bus).
+ */
+static void hv_pci_onchannelcallback(void *context)
+{
+ const int packet_size = 0x100;
+ int ret;
+ struct hv_pcibus_device *hbus = context;
+ u32 bytes_recvd;
+ u64 req_id;
+ struct vmpacket_descriptor *desc;
+ unsigned char *buffer;
+ int bufferlen = packet_size;
+ struct pci_packet *comp_packet;
+ struct pci_response *response;
+ struct pci_incoming_message *new_message;
+ struct pci_bus_relations *bus_rel;
+ struct pci_dev_incoming *dev_message;
+ struct hv_pci_dev *hpdev;
+
+ buffer = kmalloc(bufferlen, GFP_ATOMIC);
+ if (!buffer)
+ return;
+
+ while (1) {
+ ret = vmbus_recvpacket_raw(hbus->hdev->channel, buffer,
+ bufferlen, &bytes_recvd, &req_id);
+
+ if (ret == -ENOBUFS) {
+ kfree(buffer);
+ /* Handle large packet */
+ bufferlen = bytes_recvd;
+ buffer = kmalloc(bytes_recvd, GFP_ATOMIC);
+ if (!buffer)
+ return;
+ continue;
+ }
+
+ /*
+ * All incoming packets must be at least as large as a
+ * response.
+ */
+ if (bytes_recvd <= sizeof(struct pci_response)) {
+ kfree(buffer);
+ return;
+ }
+ desc = (struct vmpacket_descriptor *)buffer;
+
+ switch (desc->type) {
+ case VM_PKT_COMP:
+
+ /*
+ * The host is trusted, and thus it's safe to interpret
+ * this transaction ID as a pointer.
+ */
+ comp_packet = (struct pci_packet *)req_id;
+ response = (struct pci_response *)buffer;
+ comp_packet->completion_func(comp_packet->compl_ctxt,
+ response,
+ bytes_recvd);
+ kfree(buffer);
+ return;
+
+ case VM_PKT_DATA_INBAND:
+
+ new_message = (struct pci_incoming_message *)buffer;
+ switch (new_message->message_type.message_type) {
+ case PCI_BUS_RELATIONS:
+
+ bus_rel = (struct pci_bus_relations *)buffer;
+ if (bytes_recvd <
+ offsetof(struct pci_bus_relations, func) +
+ (sizeof(struct pci_function_description) *
+ (bus_rel->device_count))) {
+ dev_err(&hbus->hdev->device,
+ "bus relations too small\n");
+ break;
+ }
+
+ hv_pci_devices_present(hbus, bus_rel);
+ break;
+
+ case PCI_EJECT:
+
+ dev_message = (struct pci_dev_incoming *)buffer;
+ hpdev = get_pcichild_wslot(hbus,
+ dev_message->wslot.slot);
+ if (hpdev) {
+ hv_pci_eject_device(hpdev);
+ put_pcichild(hpdev,
+ hv_pcidev_ref_by_slot);
+ }
+ break;
+
+ default:
+ dev_warn(&hbus->hdev->device,
+ "Unimplemented protocol message %x\n",
+ new_message->message_type.message_type);
+ break;
+ }
+ break;
+
+ default:
+ dev_err(&hbus->hdev->device,
+ "unhandled packet type %d, tid %llx len %d\n",
+ desc->type, req_id, bytes_recvd);
+ break;
+ }
+ break;
+ }
+}
+
+/**
+ * hv_pci_protocol_negotiation() - Set up protocol
+ * @hdev: VMBus's tracking struct for this root PCI bus
+ *
+ * This driver is intended to support running on Windows 10
+ * (server) and later versions. It will not run on earlier
+ * versions, as they assume that many of the operations which
+ * Linux needs accomplished with a spinlock held were done via
+ * asynchronous messaging via VMBus. Windows 10 increases the
+ * surface area of PCI emulation so that these actions can take
+ * place by suspending a virtual processor for their duration.
+ *
+ * This function negotiates the channel protocol version,
+ * failing if the host doesn't support the necessary protocol
+ * level.
+ */
+static int hv_pci_protocol_negotiation(struct hv_device *hdev)
+{
+ struct pci_version_request *version_req;
+ struct hv_pci_compl comp_pkt;
+ struct pci_packet *pkt;
+ int ret;
+
+ /*
+ * Initiate the handshake with the host and negotiate
+ * a version that the host can support. We start with the
+ * highest version number and go down if the host cannot
+ * support it.
+ */
+ pkt = kzalloc(sizeof(*pkt) + sizeof(*version_req), GFP_KERNEL);
+ if (!pkt)
+ return -ENOMEM;
+
+ init_completion(&comp_pkt.host_event);
+ pkt->completion_func = hv_pci_generic_compl;
+ pkt->compl_ctxt = &comp_pkt;
+ version_req = (struct pci_version_request *)&pkt->message;
+ version_req->message_type.message_type = PCI_QUERY_PROTOCOL_VERSION;
+ version_req->protocol_version = PCI_PROTOCOL_VERSION_CURRENT;
+
+ ret = vmbus_sendpacket(hdev->channel, version_req,
+ sizeof(struct pci_version_request),
+ (unsigned long)pkt, VM_PKT_DATA_INBAND,
+ VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ if (ret)
+ goto exit;
+
+ wait_for_completion(&comp_pkt.host_event);
+
+ if (comp_pkt.completion_status < 0) {
+ dev_err(&hdev->device,
+ "PCI Pass-through VSP failed version request %x\n",
+ comp_pkt.completion_status);
+ ret = -EPROTO;
+ goto exit;
+ }
+
+ ret = 0;
+
+exit:
+ kfree(pkt);
+ return ret;
+}
+
+/**
+ * hv_pci_free_bridge_windows() - Release memory regions for the
+ * bus
+ * @hbus: Root PCI bus, as understood by this driver
+ */
+static void hv_pci_free_bridge_windows(struct hv_pcibus_device *hbus)
+{
+ /*
+ * Set the resources back to the way they looked when they
+ * were allocated by setting IORESOURCE_BUSY again.
+ */
+
+ if (hbus->low_mmio_space && hbus->low_mmio_res) {
+ hbus->low_mmio_res->flags |= IORESOURCE_BUSY;
+ release_mem_region(hbus->low_mmio_res->start,
+ resource_size(hbus->low_mmio_res));
+ }
+
+ if (hbus->high_mmio_space && hbus->high_mmio_res) {
+ hbus->high_mmio_res->flags |= IORESOURCE_BUSY;
+ release_mem_region(hbus->high_mmio_res->start,
+ resource_size(hbus->high_mmio_res));
+ }
+}
+
+/**
+ * hv_pci_allocate_bridge_windows() - Allocate memory regions
+ * for the bus
+ * @hbus: Root PCI bus, as understood by this driver
+ *
+ * This function calls vmbus_allocate_mmio(), which is itself a
+ * bit of a compromise. Ideally, we might change the pnp layer
+ * in the kernel such that it comprehends either PCI devices
+ * which are "grandchildren of ACPI," with some intermediate bus
+ * node (in this case, VMBus) or change it such that it
+ * understands VMBus. The pnp layer, however, has been declared
+ * deprecated, and not subject to change.
+ *
+ * The workaround, implemented here, is to ask VMBus to allocate
+ * MMIO space for this bus. VMBus itself knows which ranges are
+ * appropriate by looking at its own ACPI objects. Then, after
+ * these ranges are claimed, they're modified to look like they
+ * would have looked if the ACPI and pnp code had allocated
+ * bridge windows. These descriptors have to exist in this form
+ * in order to satisfy the code which will get invoked when the
+ * endpoint PCI function driver calls request_mem_region() or
+ * request_mem_region_exclusive().
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int hv_pci_allocate_bridge_windows(struct hv_pcibus_device *hbus)
+{
+ resource_size_t align;
+ int ret;
+
+ if (hbus->low_mmio_space) {
+ align = 1ULL << (63 - __builtin_clzll(hbus->low_mmio_space));
+ ret = vmbus_allocate_mmio(&hbus->low_mmio_res, hbus->hdev, 0,
+ (u64)(u32)0xffffffff,
+ hbus->low_mmio_space,
+ align, false);
+ if (ret) {
+ dev_err(&hbus->hdev->device,
+ "Need %#llx of low MMIO space. Consider reconfiguring the VM.\n",
+ hbus->low_mmio_space);
+ return ret;
+ }
+
+ /* Modify this resource to become a bridge window. */
+ hbus->low_mmio_res->flags |= IORESOURCE_WINDOW;
+ hbus->low_mmio_res->flags &= ~IORESOURCE_BUSY;
+ pci_add_resource(&hbus->resources_for_children,
+ hbus->low_mmio_res);
+ }
+
+ if (hbus->high_mmio_space) {
+ align = 1ULL << (63 - __builtin_clzll(hbus->high_mmio_space));
+ ret = vmbus_allocate_mmio(&hbus->high_mmio_res, hbus->hdev,
+ 0x100000000, -1,
+ hbus->high_mmio_space, align,
+ false);
+ if (ret) {
+ dev_err(&hbus->hdev->device,
+ "Need %#llx of high MMIO space. Consider reconfiguring the VM.\n",
+ hbus->high_mmio_space);
+ goto release_low_mmio;
+ }
+
+ /* Modify this resource to become a bridge window. */
+ hbus->high_mmio_res->flags |= IORESOURCE_WINDOW;
+ hbus->high_mmio_res->flags &= ~IORESOURCE_BUSY;
+ pci_add_resource(&hbus->resources_for_children,
+ hbus->high_mmio_res);
+ }
+
+ return 0;
+
+release_low_mmio:
+ if (hbus->low_mmio_res) {
+ release_mem_region(hbus->low_mmio_res->start,
+ resource_size(hbus->low_mmio_res));
+ }
+
+ return ret;
+}
+
+/**
+ * hv_allocate_config_window() - Find MMIO space for PCI Config
+ * @hbus: Root PCI bus, as understood by this driver
+ *
+ * This function claims memory-mapped I/O space for accessing
+ * configuration space for the functions on this bus.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int hv_allocate_config_window(struct hv_pcibus_device *hbus)
+{
+ int ret;
+
+ /*
+ * Set up a region of MMIO space to use for accessing configuration
+ * space.
+ */
+ ret = vmbus_allocate_mmio(&hbus->mem_config, hbus->hdev, 0, -1,
+ PCI_CONFIG_MMIO_LENGTH, 0x1000, false);
+ if (ret)
+ return ret;
+
+ /*
+ * vmbus_allocate_mmio() gets used for allocating both device endpoint
+ * resource claims (those which cannot be overlapped) and the ranges
+ * which are valid for the children of this bus, which are intended
+ * to be overlapped by those children. Set the flag on this claim
+ * meaning that this region can't be overlapped.
+ */
+
+ hbus->mem_config->flags |= IORESOURCE_BUSY;
+
+ return 0;
+}
+
+static void hv_free_config_window(struct hv_pcibus_device *hbus)
+{
+ release_mem_region(hbus->mem_config->start, PCI_CONFIG_MMIO_LENGTH);
+}
+
+/**
+ * hv_pci_enter_d0() - Bring the "bus" into the D0 power state
+ * @hdev: VMBus's tracking struct for this root PCI bus
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int hv_pci_enter_d0(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ struct pci_bus_d0_entry *d0_entry;
+ struct hv_pci_compl comp_pkt;
+ struct pci_packet *pkt;
+ int ret;
+
+ /*
+ * Tell the host that the bus is ready to use, and moved into the
+ * powered-on state. This includes telling the host which region
+ * of memory-mapped I/O space has been chosen for configuration space
+ * access.
+ */
+ pkt = kzalloc(sizeof(*pkt) + sizeof(*d0_entry), GFP_KERNEL);
+ if (!pkt)
+ return -ENOMEM;
+
+ init_completion(&comp_pkt.host_event);
+ pkt->completion_func = hv_pci_generic_compl;
+ pkt->compl_ctxt = &comp_pkt;
+ d0_entry = (struct pci_bus_d0_entry *)&pkt->message;
+ d0_entry->message_type.message_type = PCI_BUS_D0ENTRY;
+ d0_entry->mmio_base = hbus->mem_config->start;
+
+ ret = vmbus_sendpacket(hdev->channel, d0_entry, sizeof(*d0_entry),
+ (unsigned long)pkt, VM_PKT_DATA_INBAND,
+ VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ if (ret)
+ goto exit;
+
+ wait_for_completion(&comp_pkt.host_event);
+
+ if (comp_pkt.completion_status < 0) {
+ dev_err(&hdev->device,
+ "PCI Pass-through VSP failed D0 Entry with status %x\n",
+ comp_pkt.completion_status);
+ ret = -EPROTO;
+ goto exit;
+ }
+
+ ret = 0;
+
+exit:
+ kfree(pkt);
+ return ret;
+}
+
+/**
+ * hv_pci_query_relations() - Ask host to send list of child
+ * devices
+ * @hdev: VMBus's tracking struct for this root PCI bus
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int hv_pci_query_relations(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ struct pci_message message;
+ struct completion comp;
+ int ret;
+
+ /* Ask the host to send along the list of child devices */
+ init_completion(&comp);
+ if (cmpxchg(&hbus->survey_event, NULL, &comp))
+ return -ENOTEMPTY;
+
+ memset(&message, 0, sizeof(message));
+ message.message_type = PCI_QUERY_BUS_RELATIONS;
+
+ ret = vmbus_sendpacket(hdev->channel, &message, sizeof(message),
+ 0, VM_PKT_DATA_INBAND, 0);
+ if (ret)
+ return ret;
+
+ wait_for_completion(&comp);
+ return 0;
+}
+
+/**
+ * hv_send_resources_allocated() - Report local resource choices
+ * @hdev: VMBus's tracking struct for this root PCI bus
+ *
+ * The host OS is expecting to be sent a request as a message
+ * which contains all the resources that the device will use.
+ * The response contains those same resources, "translated"
+ * which is to say, the values which should be used by the
+ * hardware, when it delivers an interrupt. (MMIO resources are
+ * used in local terms.) This is nice for Windows, and lines up
+ * with the FDO/PDO split, which doesn't exist in Linux. Linux
+ * is deeply expecting to scan an emulated PCI configuration
+ * space. So this message is sent here only to drive the state
+ * machine on the host forward.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int hv_send_resources_allocated(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ struct pci_resources_assigned *res_assigned;
+ struct hv_pci_compl comp_pkt;
+ struct hv_pci_dev *hpdev;
+ struct pci_packet *pkt;
+ u32 wslot;
+ int ret;
+
+ pkt = kmalloc(sizeof(*pkt) + sizeof(*res_assigned), GFP_KERNEL);
+ if (!pkt)
+ return -ENOMEM;
+
+ ret = 0;
+
+ for (wslot = 0; wslot < 256; wslot++) {
+ hpdev = get_pcichild_wslot(hbus, wslot);
+ if (!hpdev)
+ continue;
+
+ memset(pkt, 0, sizeof(*pkt) + sizeof(*res_assigned));
+ init_completion(&comp_pkt.host_event);
+ pkt->completion_func = hv_pci_generic_compl;
+ pkt->compl_ctxt = &comp_pkt;
+ pkt->message.message_type = PCI_RESOURCES_ASSIGNED;
+ res_assigned = (struct pci_resources_assigned *)&pkt->message;
+ res_assigned->wslot.slot = hpdev->desc.win_slot.slot;
+
+ put_pcichild(hpdev, hv_pcidev_ref_by_slot);
+
+ ret = vmbus_sendpacket(
+ hdev->channel, &pkt->message,
+ sizeof(*res_assigned),
+ (unsigned long)pkt,
+ VM_PKT_DATA_INBAND,
+ VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ if (ret)
+ break;
+
+ wait_for_completion(&comp_pkt.host_event);
+
+ if (comp_pkt.completion_status < 0) {
+ ret = -EPROTO;
+ dev_err(&hdev->device,
+ "resource allocated returned 0x%x",
+ comp_pkt.completion_status);
+ break;
+ }
+ }
+
+ kfree(pkt);
+ return ret;
+}
+
+/**
+ * hv_send_resources_released() - Report local resources
+ * released
+ * @hdev: VMBus's tracking struct for this root PCI bus
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int hv_send_resources_released(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ struct pci_child_message pkt;
+ struct hv_pci_dev *hpdev;
+ u32 wslot;
+ int ret;
+
+ for (wslot = 0; wslot < 256; wslot++) {
+ hpdev = get_pcichild_wslot(hbus, wslot);
+ if (!hpdev)
+ continue;
+
+ memset(&pkt, 0, sizeof(pkt));
+ pkt.message_type = PCI_RESOURCES_RELEASED;
+ pkt.wslot.slot = hpdev->desc.win_slot.slot;
+
+ put_pcichild(hpdev, hv_pcidev_ref_by_slot);
+
+ ret = vmbus_sendpacket(hdev->channel, &pkt, sizeof(pkt), 0,
+ VM_PKT_DATA_INBAND, 0);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static void get_hvpcibus(struct hv_pcibus_device *hbus)
+{
+ atomic_inc(&hbus->remove_lock);
+}
+
+static void put_hvpcibus(struct hv_pcibus_device *hbus)
+{
+ if (atomic_dec_and_test(&hbus->remove_lock))
+ complete(&hbus->remove_event);
+}
+
+/**
+ * hv_pci_probe() - New VMBus channel probe, for a root PCI bus
+ * @hdev: VMBus's tracking struct for this root PCI bus
+ * @dev_id: Identifies the device itself
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int hv_pci_probe(struct hv_device *hdev,
+ const struct hv_vmbus_device_id *dev_id)
+{
+ struct hv_pcibus_device *hbus;
+ int ret;
+
+ hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
+ if (!hbus)
+ return -ENOMEM;
+
+ /*
+ * The PCI bus "domain" is what is called "segment" in ACPI and
+ * other specs. Pull it from the instance ID, to get something
+ * unique. Bytes 8 and 9 are what is used in Windows guests, so
+ * do the same thing for consistency. Note that, since this code
+ * only runs in a Hyper-V VM, Hyper-V can (and does) guarantee
+ * that (1) the only domain in use for something that looks like
+ * a physical PCI bus (which is actually emulated by the
+ * hypervisor) is domain 0 and (2) there will be no overlap
+ * between domains derived from these instance IDs in the same
+ * VM.
+ */
+ hbus->sysdata.domain = hdev->dev_instance.b[9] |
+ hdev->dev_instance.b[8] << 8;
+
+ hbus->hdev = hdev;
+ atomic_inc(&hbus->remove_lock);
+ INIT_LIST_HEAD(&hbus->children);
+ INIT_LIST_HEAD(&hbus->dr_list);
+ INIT_LIST_HEAD(&hbus->resources_for_children);
+ spin_lock_init(&hbus->config_lock);
+ spin_lock_init(&hbus->device_list_lock);
+ sema_init(&hbus->enum_sem, 1);
+ init_completion(&hbus->remove_event);
+
+ ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
+ hv_pci_onchannelcallback, hbus);
+ if (ret)
+ goto free_bus;
+
+ hv_set_drvdata(hdev, hbus);
+
+ ret = hv_pci_protocol_negotiation(hdev);
+ if (ret)
+ goto close;
+
+ ret = hv_allocate_config_window(hbus);
+ if (ret)
+ goto close;
+
+ hbus->cfg_addr = ioremap(hbus->mem_config->start,
+ PCI_CONFIG_MMIO_LENGTH);
+ if (!hbus->cfg_addr) {
+ dev_err(&hdev->device,
+ "Unable to map a virtual address for config space\n");
+ ret = -ENOMEM;
+ goto free_config;
+ }
+
+ hbus->sysdata.fwnode = irq_domain_alloc_fwnode(hbus);
+ if (!hbus->sysdata.fwnode) {
+ ret = -ENOMEM;
+ goto unmap;
+ }
+
+ ret = hv_pcie_init_irq_domain(hbus);
+ if (ret)
+ goto free_fwnode;
+
+ ret = hv_pci_query_relations(hdev);
+ if (ret)
+ goto free_irq_domain;
+
+ ret = hv_pci_enter_d0(hdev);
+ if (ret)
+ goto free_irq_domain;
+
+ ret = hv_pci_allocate_bridge_windows(hbus);
+ if (ret)
+ goto free_irq_domain;
+
+ ret = hv_send_resources_allocated(hdev);
+ if (ret)
+ goto free_windows;
+
+ prepopulate_bars(hbus);
+
+ hbus->state = hv_pcibus_probed;
+
+ ret = create_root_hv_pci_bus(hbus);
+ if (ret)
+ goto free_windows;
+
+ return 0;
+
+free_windows:
+ hv_pci_free_bridge_windows(hbus);
+free_irq_domain:
+ irq_domain_remove(hbus->irq_domain);
+free_fwnode:
+ irq_domain_free_fwnode(hbus->sysdata.fwnode);
+unmap:
+ iounmap(hbus->cfg_addr);
+free_config:
+ hv_free_config_window(hbus);
+close:
+ vmbus_close(hdev->channel);
+free_bus:
+ kfree(hbus);
+ return ret;
+}
+
+/**
+ * hv_pci_remove() - Remove routine for this VMBus channel
+ * @hdev: VMBus's tracking struct for this root PCI bus
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int hv_pci_remove(struct hv_device *hdev)
+{
+ int ret;
+ struct hv_pcibus_device *hbus;
+ union {
+ struct pci_packet teardown_packet;
+ u8 buffer[0x100];
+ } pkt;
+ struct pci_bus_relations relations;
+ struct hv_pci_compl comp_pkt;
+
+ hbus = hv_get_drvdata(hdev);
+
+ ret = hv_send_resources_released(hdev);
+ if (ret)
+ dev_err(&hdev->device,
+ "Couldn't send resources released packet(s)\n");
+
+ memset(&pkt.teardown_packet, 0, sizeof(pkt.teardown_packet));
+ init_completion(&comp_pkt.host_event);
+ pkt.teardown_packet.completion_func = hv_pci_generic_compl;
+ pkt.teardown_packet.compl_ctxt = &comp_pkt;
+ pkt.teardown_packet.message.message_type = PCI_BUS_D0EXIT;
+
+ ret = vmbus_sendpacket(hdev->channel, &pkt.teardown_packet.message,
+ sizeof(struct pci_message),
+ (unsigned long)&pkt.teardown_packet,
+ VM_PKT_DATA_INBAND,
+ VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ if (!ret)
+ wait_for_completion_timeout(&comp_pkt.host_event, 10 * HZ);
+
+ if (hbus->state == hv_pcibus_installed) {
+ /* Remove the bus from PCI's point of view. */
+ pci_lock_rescan_remove();
+ pci_stop_root_bus(hbus->pci_bus);
+ pci_remove_root_bus(hbus->pci_bus);
+ pci_unlock_rescan_remove();
+ }
+
+ vmbus_close(hdev->channel);
+
+ /* Delete any children which might still exist. */
+ memset(&relations, 0, sizeof(relations));
+ hv_pci_devices_present(hbus, &relations);
+
+ iounmap(hbus->cfg_addr);
+ hv_free_config_window(hbus);
+ pci_free_resource_list(&hbus->resources_for_children);
+ hv_pci_free_bridge_windows(hbus);
+ irq_domain_remove(hbus->irq_domain);
+ irq_domain_free_fwnode(hbus->sysdata.fwnode);
+ put_hvpcibus(hbus);
+ wait_for_completion(&hbus->remove_event);
+ kfree(hbus);
+ return 0;
+}
+
+static const struct hv_vmbus_device_id hv_pci_id_table[] = {
+ /* PCI Pass-through Class ID */
+ /* 44C4F61D-4444-4400-9D52-802E27EDE19F */
+ { HV_PCIE_GUID, },
+ { },
+};
+
+MODULE_DEVICE_TABLE(vmbus, hv_pci_id_table);
+
+static struct hv_driver hv_pci_drv = {
+ .name = "hv_pci",
+ .id_table = hv_pci_id_table,
+ .probe = hv_pci_probe,
+ .remove = hv_pci_remove,
+};
+
+static void __exit exit_hv_pci_drv(void)
+{
+ vmbus_driver_unregister(&hv_pci_drv);
+}
+
+static int __init init_hv_pci_drv(void)
+{
+ return vmbus_driver_register(&hv_pci_drv);
+}
+
+module_init(init_hv_pci_drv);
+module_exit(exit_hv_pci_drv);
+
+MODULE_DESCRIPTION("Hyper-V PCI");
+MODULE_LICENSE("GPL v2");