xen.c

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/*
 * Xen PCI - handle PCI (INTx) and MSI infrastructure calls for PV, HVM and
 * initial domain support. We also handle the DSDT _PRT callbacks for GSI's
 * used in HVM and initial domain mode (PV does not parse ACPI, so it has no
 * concept of GSIs). Under PV we hook under the pnbbios API for IRQs and
 * 0xcf8 PCI configuration read/write.
 *
 *   Author: Ryan Wilson <[email protected]>
 *           Konrad Rzeszutek Wilk <[email protected]>
 *           Stefano Stabellini <[email protected]>
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/acpi.h>

#include <linux/io.h>
#include <asm/io_apic.h>
#include <asm/pci_x86.h>

#include <asm/xen/hypervisor.h>

#include <xen/features.h>
#include <xen/events.h>
#include <asm/xen/pci.h>

static int xen_pcifront_enable_irq(struct pci_dev *dev)
{
    int rc;
    int share = 1;
    int pirq;
    u8 gsi;

    rc = pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &gsi);
    if (rc < 0) {
        dev_warn(&dev->dev, "Xen PCI: failed to read interrupt line: %d\n",
             rc);
        return rc;
    }
    /* In PV DomU the Xen PCI backend puts the PIRQ in the interrupt line.*/
    pirq = gsi;

    if (gsi < NR_IRQS_LEGACY)
        share = 0;

    rc = xen_bind_pirq_gsi_to_irq(gsi, pirq, share, "pcifront");
    if (rc < 0) {
        dev_warn(&dev->dev, "Xen PCI: failed to bind GSI%d (PIRQ%d) to IRQ: %d\n",
             gsi, pirq, rc);
        return rc;
    }

    dev->irq = rc;
    dev_info(&dev->dev, "Xen PCI mapped GSI%d to IRQ%d\n", gsi, dev->irq);
    return 0;
}

#ifdef CONFIG_ACPI
static int xen_register_pirq(u32 gsi, int gsi_override, int triggering,
                 bool set_pirq)
{
    int rc, pirq = -1, irq = -1;
    struct physdev_map_pirq map_irq;
    int shareable = 0;
    char *name;

    irq = xen_irq_from_gsi(gsi);
    if (irq > 0)
        return irq;

    if (set_pirq)
        pirq = gsi;

    map_irq.domid = DOMID_SELF;
    map_irq.type = MAP_PIRQ_TYPE_GSI;
    map_irq.index = gsi;
    map_irq.pirq = pirq;

    rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
    if (rc) {
        printk(KERN_WARNING "xen map irq failed %d\n", rc);
        return -1;
    }

    if (triggering == ACPI_EDGE_SENSITIVE) {
        shareable = 0;
        name = "ioapic-edge";
    } else {
        shareable = 1;
        name = "ioapic-level";
    }

    if (gsi_override >= 0)
        gsi = gsi_override;

    irq = xen_bind_pirq_gsi_to_irq(gsi, map_irq.pirq, shareable, name);
    if (irq < 0)
        goto out;

    printk(KERN_DEBUG "xen: --> pirq=%d -> irq=%d (gsi=%d)\n", map_irq.pirq, irq, gsi);
out:
    return irq;
}

static int acpi_register_gsi_xen_hvm(struct device *dev, u32 gsi,
                     int trigger, int polarity)
{
    if (!xen_hvm_domain())
        return -1;

    return xen_register_pirq(gsi, -1 /* no GSI override */, trigger,
                 false /* no mapping of GSI to PIRQ */);
}

#ifdef CONFIG_XEN_DOM0
static int xen_register_gsi(u32 gsi, int gsi_override, int triggering, int polarity)
{
    int rc, irq;
    struct physdev_setup_gsi setup_gsi;

    if (!xen_pv_domain())
        return -1;

    printk(KERN_DEBUG "xen: registering gsi %u triggering %d polarity %d\n",
            gsi, triggering, polarity);

    irq = xen_register_pirq(gsi, gsi_override, triggering, true);

    setup_gsi.gsi = gsi;
    setup_gsi.triggering = (triggering == ACPI_EDGE_SENSITIVE ? 0 : 1);
    setup_gsi.polarity = (polarity == ACPI_ACTIVE_HIGH ? 0 : 1);

    rc = HYPERVISOR_physdev_op(PHYSDEVOP_setup_gsi, &setup_gsi);
    if (rc == -EEXIST)
        printk(KERN_INFO "Already setup the GSI :%d\n", gsi);
    else if (rc) {
        printk(KERN_ERR "Failed to setup GSI :%d, err_code:%d\n",
                gsi, rc);
    }

    return irq;
}

static int acpi_register_gsi_xen(struct device *dev, u32 gsi,
                 int trigger, int polarity)
{
    return xen_register_gsi(gsi, -1 /* no GSI override */, trigger, polarity);
}
#endif
#endif

#if defined(CONFIG_PCI_MSI)
#include <linux/msi.h>
#include <asm/msidef.h>

struct xen_pci_frontend_ops *xen_pci_frontend;
EXPORT_SYMBOL_GPL(xen_pci_frontend);

static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
    int irq, ret, i;
    struct msi_desc *msidesc;
    int *v;

    v = kzalloc(sizeof(int) * max(1, nvec), GFP_KERNEL);
    if (!v)
        return -ENOMEM;

    if (type == PCI_CAP_ID_MSIX)
        ret = xen_pci_frontend_enable_msix(dev, v, nvec);
    else
        ret = xen_pci_frontend_enable_msi(dev, v);
    if (ret)
        goto error;
    i = 0;
    list_for_each_entry(msidesc, &dev->msi_list, list) {
        irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i], 0,
                           (type == PCI_CAP_ID_MSIX) ?
                           "pcifront-msi-x" :
                           "pcifront-msi",
                        DOMID_SELF);
        if (irq < 0) {
            ret = irq;
            goto free;
        }
        i++;
    }
    kfree(v);
    return 0;

error:
    dev_err(&dev->dev, "Xen PCI frontend has not registered MSI/MSI-X support!\n");
free:
    kfree(v);
    return ret;
}

#define XEN_PIRQ_MSI_DATA  (MSI_DATA_TRIGGER_EDGE | \
        MSI_DATA_LEVEL_ASSERT | (3 << 8) | MSI_DATA_VECTOR(0))

static void xen_msi_compose_msg(struct pci_dev *pdev, unsigned int pirq,
        struct msi_msg *msg)
{
    /* We set vector == 0 to tell the hypervisor we don't care about it,
     * but we want a pirq setup instead.
     * We use the dest_id field to pass the pirq that we want. */
    msg->address_hi = MSI_ADDR_BASE_HI | MSI_ADDR_EXT_DEST_ID(pirq);
    msg->address_lo =
        MSI_ADDR_BASE_LO |
        MSI_ADDR_DEST_MODE_PHYSICAL |
        MSI_ADDR_REDIRECTION_CPU |
        MSI_ADDR_DEST_ID(pirq);

    msg->data = XEN_PIRQ_MSI_DATA;
}

static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
    int irq, pirq;
    struct msi_desc *msidesc;
    struct msi_msg msg;

    list_for_each_entry(msidesc, &dev->msi_list, list) {
        __read_msi_msg(msidesc, &msg);
        pirq = MSI_ADDR_EXT_DEST_ID(msg.address_hi) |
            ((msg.address_lo >> MSI_ADDR_DEST_ID_SHIFT) & 0xff);
        if (msg.data != XEN_PIRQ_MSI_DATA ||
            xen_irq_from_pirq(pirq) < 0) {
            pirq = xen_allocate_pirq_msi(dev, msidesc);
            if (pirq < 0) {
                irq = -ENODEV;
                goto error;
            }
            xen_msi_compose_msg(dev, pirq, &msg);
            __write_msi_msg(msidesc, &msg);
            dev_dbg(&dev->dev, "xen: msi bound to pirq=%d\n", pirq);
        } else {
            dev_dbg(&dev->dev,
                "xen: msi already bound to pirq=%d\n", pirq);
        }
        irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq, 0,
                           (type == PCI_CAP_ID_MSIX) ?
                           "msi-x" : "msi",
                           DOMID_SELF);
        if (irq < 0)
            goto error;
        dev_dbg(&dev->dev,
            "xen: msi --> pirq=%d --> irq=%d\n", pirq, irq);
    }
    return 0;

error:
    dev_err(&dev->dev,
        "Xen PCI frontend has not registered MSI/MSI-X support!\n");
    return irq;
}

#ifdef CONFIG_XEN_DOM0
static bool __read_mostly pci_seg_supported = true;

static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
    int ret = 0;
    struct msi_desc *msidesc;

    list_for_each_entry(msidesc, &dev->msi_list, list) {
        struct physdev_map_pirq map_irq;
        domid_t domid;

        domid = ret = xen_find_device_domain_owner(dev);
        /* N.B. Casting int's -ENODEV to uint16_t results in 0xFFED,
         * hence check ret value for < 0. */
        if (ret < 0)
            domid = DOMID_SELF;

        memset(&map_irq, 0, sizeof(map_irq));
        map_irq.domid = domid;
        map_irq.type = MAP_PIRQ_TYPE_MSI_SEG;
        map_irq.index = -1;
        map_irq.pirq = -1;
        map_irq.bus = dev->bus->number |
                  (pci_domain_nr(dev->bus) << 16);
        map_irq.devfn = dev->devfn;

        if (type == PCI_CAP_ID_MSIX) {
            int pos;
            u32 table_offset, bir;

            pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);

            pci_read_config_dword(dev, pos + PCI_MSIX_TABLE,
                          &table_offset);
            bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);

            map_irq.table_base = pci_resource_start(dev, bir);
            map_irq.entry_nr = msidesc->msi_attrib.entry_nr;
        }

        ret = -EINVAL;
        if (pci_seg_supported)
            ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
                            &map_irq);
        if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
            map_irq.type = MAP_PIRQ_TYPE_MSI;
            map_irq.index = -1;
            map_irq.pirq = -1;
            map_irq.bus = dev->bus->number;
            ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
                            &map_irq);
            if (ret != -EINVAL)
                pci_seg_supported = false;
        }
        if (ret) {
            dev_warn(&dev->dev, "xen map irq failed %d for %d domain\n",
                 ret, domid);
            goto out;
        }

        ret = xen_bind_pirq_msi_to_irq(dev, msidesc,
                           map_irq.pirq, map_irq.index,
                           (type == PCI_CAP_ID_MSIX) ?
                           "msi-x" : "msi",
                        domid);
        if (ret < 0)
            goto out;
    }
    ret = 0;
out:
    return ret;
}

static void xen_initdom_restore_msi_irqs(struct pci_dev *dev, int irq)
{
    int ret = 0;

    if (pci_seg_supported) {
        struct physdev_pci_device restore_ext;

        restore_ext.seg = pci_domain_nr(dev->bus);
        restore_ext.bus = dev->bus->number;
        restore_ext.devfn = dev->devfn;
        ret = HYPERVISOR_physdev_op(PHYSDEVOP_restore_msi_ext,
                    &restore_ext);
        if (ret == -ENOSYS)
            pci_seg_supported = false;
        WARN(ret && ret != -ENOSYS, "restore_msi_ext -> %d\n", ret);
    }
    if (!pci_seg_supported) {
        struct physdev_restore_msi restore;

        restore.bus = dev->bus->number;
        restore.devfn = dev->devfn;
        ret = HYPERVISOR_physdev_op(PHYSDEVOP_restore_msi, &restore);
        WARN(ret && ret != -ENOSYS, "restore_msi -> %d\n", ret);
    }
}
#endif

static void xen_teardown_msi_irqs(struct pci_dev *dev)
{
    struct msi_desc *msidesc;

    msidesc = list_entry(dev->msi_list.next, struct msi_desc, list);
    if (msidesc->msi_attrib.is_msix)
        xen_pci_frontend_disable_msix(dev);
    else
        xen_pci_frontend_disable_msi(dev);

    /* Free the IRQ's and the msidesc using the generic code. */
    default_teardown_msi_irqs(dev);
}

static void xen_teardown_msi_irq(unsigned int irq)
{
    xen_destroy_irq(irq);
}

#endif

int __init pci_xen_init(void)
{
    if (!xen_pv_domain() || xen_initial_domain())
        return -ENODEV;

    printk(KERN_INFO "PCI: setting up Xen PCI frontend stub\n");

    pcibios_set_cache_line_size();

    pcibios_enable_irq = xen_pcifront_enable_irq;
    pcibios_disable_irq = NULL;

#ifdef CONFIG_ACPI
    /* Keep ACPI out of the picture */
    acpi_noirq = 1;
#endif

#ifdef CONFIG_PCI_MSI
    x86_msi.setup_msi_irqs = xen_setup_msi_irqs;
    x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
    x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs;
#endif
    return 0;
}

int __init pci_xen_hvm_init(void)
{
    if (!xen_have_vector_callback || !xen_feature(XENFEAT_hvm_pirqs))
        return 0;

#ifdef CONFIG_ACPI
    /*
     * We don't want to change the actual ACPI delivery model,
     * just how GSIs get registered.
     */
    __acpi_register_gsi = acpi_register_gsi_xen_hvm;
#endif

#ifdef CONFIG_PCI_MSI
    x86_msi.setup_msi_irqs = xen_hvm_setup_msi_irqs;
    x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
#endif
    return 0;
}

#ifdef CONFIG_XEN_DOM0
static __init void xen_setup_acpi_sci(void)
{
    int rc;
    int trigger, polarity;
    int gsi = acpi_sci_override_gsi;
    int irq = -1;
    int gsi_override = -1;

    if (!gsi)
        return;

    rc = acpi_get_override_irq(gsi, &trigger, &polarity);
    if (rc) {
        printk(KERN_WARNING "xen: acpi_get_override_irq failed for acpi"
                " sci, rc=%d\n", rc);
        return;
    }
    trigger = trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE;
    polarity = polarity ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;

    printk(KERN_INFO "xen: sci override: global_irq=%d trigger=%d "
            "polarity=%d\n", gsi, trigger, polarity);

    /* Before we bind the GSI to a Linux IRQ, check whether
     * we need to override it with bus_irq (IRQ) value. Usually for
     * IRQs below IRQ_LEGACY_IRQ this holds IRQ == GSI, as so:
     *  ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 low level)
     * but there are oddballs where the IRQ != GSI:
     *  ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 20 low level)
     * which ends up being: gsi_to_irq[9] == 20
     * (which is what acpi_gsi_to_irq ends up calling when starting the
     * the ACPI interpreter and keels over since IRQ 9 has not been
     * setup as we had setup IRQ 20 for it).
     */
    if (acpi_gsi_to_irq(gsi, &irq) == 0) {
        /* Use the provided value if it's valid. */
        if (irq >= 0)
            gsi_override = irq;
    }

    gsi = xen_register_gsi(gsi, gsi_override, trigger, polarity);
    printk(KERN_INFO "xen: acpi sci %d\n", gsi);

    return;
}

int __init pci_xen_initial_domain(void)
{
    int irq;

#ifdef CONFIG_PCI_MSI
    x86_msi.setup_msi_irqs = xen_initdom_setup_msi_irqs;
    x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
    x86_msi.restore_msi_irqs = xen_initdom_restore_msi_irqs;
#endif
    xen_setup_acpi_sci();
    __acpi_register_gsi = acpi_register_gsi_xen;
    /* Pre-allocate legacy irqs */
    for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
        int trigger, polarity;

        if (acpi_get_override_irq(irq, &trigger, &polarity) == -1)
            continue;

        xen_register_pirq(irq, -1 /* no GSI override */,
            trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE,
            true /* Map GSI to PIRQ */);
    }
    if (0 == nr_ioapics) {
        for (irq = 0; irq < NR_IRQS_LEGACY; irq++)
            xen_bind_pirq_gsi_to_irq(irq, irq, 0, "xt-pic");
    }
    return 0;
}

struct xen_device_domain_owner {
    domid_t domain;
    struct pci_dev *dev;
    struct list_head list;
};

static DEFINE_SPINLOCK(dev_domain_list_spinlock);
static struct list_head dev_domain_list = LIST_HEAD_INIT(dev_domain_list);

static struct xen_device_domain_owner *find_device(struct pci_dev *dev)
{
    struct xen_device_domain_owner *owner;

    list_for_each_entry(owner, &dev_domain_list, list) {
        if (owner->dev == dev)
            return owner;
    }
    return NULL;
}

int xen_find_device_domain_owner(struct pci_dev *dev)
{
    struct xen_device_domain_owner *owner;
    int domain = -ENODEV;

    spin_lock(&dev_domain_list_spinlock);
    owner = find_device(dev);
    if (owner)
        domain = owner->domain;
    spin_unlock(&dev_domain_list_spinlock);
    return domain;
}
EXPORT_SYMBOL_GPL(xen_find_device_domain_owner);

int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain)
{
    struct xen_device_domain_owner *owner;

    owner = kzalloc(sizeof(struct xen_device_domain_owner), GFP_KERNEL);
    if (!owner)
        return -ENODEV;

    spin_lock(&dev_domain_list_spinlock);
    if (find_device(dev)) {
        spin_unlock(&dev_domain_list_spinlock);
        kfree(owner);
        return -EEXIST;
    }
    owner->domain = domain;
    owner->dev = dev;
    list_add_tail(&owner->list, &dev_domain_list);
    spin_unlock(&dev_domain_list_spinlock);
    return 0;
}
EXPORT_SYMBOL_GPL(xen_register_device_domain_owner);

int xen_unregister_device_domain_owner(struct pci_dev *dev)
{
    struct xen_device_domain_owner *owner;

    spin_lock(&dev_domain_list_spinlock);
    owner = find_device(dev);
    if (!owner) {
        spin_unlock(&dev_domain_list_spinlock);
        return -ENODEV;
    }
    list_del(&owner->list);
    spin_unlock(&dev_domain_list_spinlock);
    kfree(owner);
    return 0;
}
EXPORT_SYMBOL_GPL(xen_unregister_device_domain_owner);
#endif