Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 667 insertions, 0 deletions

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
new file mode 100644
index 000000000..326d6d173
--- /dev/null
+++ b/arch/x86/pci/xen.c
@@ -0,0 +1,667 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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 <hap9@epoch.ncsc.mil>
+ *           Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+ *           Stefano Stabellini <stefano.stabellini@eu.citrix.com>
+ */
+#include <linux/export.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>
+#include <asm/xen/cpuid.h>
+#include <asm/apic.h>
+#include <asm/acpi.h>
+#include <asm/i8259.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_legacy_irqs())
+		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 triggering, bool set_pirq)
+{
+	int rc, pirq = -1, irq;
+	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";
+	}
+
+	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, trigger,
+				 false /* no mapping of GSI to PIRQ */);
+}
+
+#ifdef CONFIG_XEN_DOM0
+static int xen_register_gsi(u32 gsi, 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, 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, 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);
+
+struct xen_msi_ops {
+	int (*setup_msi_irqs)(struct pci_dev *dev, int nvec, int type);
+	void (*teardown_msi_irqs)(struct pci_dev *dev);
+};
+
+static struct xen_msi_ops xen_msi_ops __ro_after_init;
+
+static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+	int irq, ret, i;
+	struct msi_desc *msidesc;
+	int *v;
+
+	if (type == PCI_CAP_ID_MSI && nvec > 1)
+		return 1;
+
+	v = kcalloc(max(1, nvec), sizeof(int), 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;
+	for_each_pci_msi_entry(msidesc, dev) {
+		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
+					       (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:
+	if (ret == -ENOSYS)
+		dev_err(&dev->dev, "Xen PCI frontend has not registered MSI/MSI-X support!\n");
+	else if (ret)
+		dev_err(&dev->dev, "Xen PCI frontend error: %d!\n", ret);
+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;
+
+	if (type == PCI_CAP_ID_MSI && nvec > 1)
+		return 1;
+
+	for_each_pci_msi_entry(msidesc, dev) {
+		pirq = xen_allocate_pirq_msi(dev, msidesc);
+		if (pirq < 0) {
+			irq = -ENODEV;
+			goto error;
+		}
+		xen_msi_compose_msg(dev, pirq, &msg);
+		__pci_write_msi_msg(msidesc, &msg);
+		dev_dbg(&dev->dev, "xen: msi bound to pirq=%d\n", pirq);
+		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
+					       (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, "Failed to create MSI%s! ret=%d!\n",
+		type == PCI_CAP_ID_MSI ? "" : "-X", irq);
+	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;
+
+	for_each_pci_msi_entry(msidesc, dev) {
+		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_MSI && nvec > 1) {
+			map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
+			map_irq.entry_nr = nvec;
+		} else if (type == PCI_CAP_ID_MSIX) {
+			int pos;
+			unsigned long flags;
+			u32 table_offset, bir;
+
+			pos = dev->msix_cap;
+			pci_read_config_dword(dev, pos + PCI_MSIX_TABLE,
+					      &table_offset);
+			bir = (u8)(table_offset & PCI_MSIX_TABLE_BIR);
+			flags = pci_resource_flags(dev, bir);
+			if (!flags || (flags & IORESOURCE_UNSET))
+				return -EINVAL;
+
+			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 (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
+			/*
+			 * If MAP_PIRQ_TYPE_MULTI_MSI is not available
+			 * there's nothing else we can do in this case.
+			 * Just set ret > 0 so driver can retry with
+			 * single MSI.
+			 */
+			ret = 1;
+			goto out;
+		}
+		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,
+		                               (type == PCI_CAP_ID_MSI) ? nvec : 1,
+		                               (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 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);
+	}
+}
+#else /* CONFIG_XEN_DOM0 */
+#define xen_initdom_setup_msi_irqs	NULL
+#define xen_initdom_restore_msi_irqs	NULL
+#endif /* !CONFIG_XEN_DOM0 */
+
+static void xen_teardown_msi_irqs(struct pci_dev *dev)
+{
+	struct msi_desc *msidesc;
+	int i;
+
+	for_each_pci_msi_entry(msidesc, dev) {
+		if (msidesc->irq) {
+			for (i = 0; i < msidesc->nvec_used; i++)
+				xen_destroy_irq(msidesc->irq + i);
+		}
+	}
+}
+
+static void xen_pv_teardown_msi_irqs(struct pci_dev *dev)
+{
+	struct msi_desc *msidesc = first_pci_msi_entry(dev);
+
+	if (msidesc->msi_attrib.is_msix)
+		xen_pci_frontend_disable_msix(dev);
+	else
+		xen_pci_frontend_disable_msi(dev);
+
+	xen_teardown_msi_irqs(dev);
+}
+
+static int xen_msi_domain_alloc_irqs(struct irq_domain *domain,
+				     struct device *dev,  int nvec)
+{
+	int type;
+
+	if (WARN_ON_ONCE(!dev_is_pci(dev)))
+		return -EINVAL;
+
+	if (first_msi_entry(dev)->msi_attrib.is_msix)
+		type = PCI_CAP_ID_MSIX;
+	else
+		type = PCI_CAP_ID_MSI;
+
+	return xen_msi_ops.setup_msi_irqs(to_pci_dev(dev), nvec, type);
+}
+
+static void xen_msi_domain_free_irqs(struct irq_domain *domain,
+				     struct device *dev)
+{
+	if (WARN_ON_ONCE(!dev_is_pci(dev)))
+		return;
+
+	xen_msi_ops.teardown_msi_irqs(to_pci_dev(dev));
+}
+
+static struct msi_domain_ops xen_pci_msi_domain_ops = {
+	.domain_alloc_irqs	= xen_msi_domain_alloc_irqs,
+	.domain_free_irqs	= xen_msi_domain_free_irqs,
+};
+
+static struct msi_domain_info xen_pci_msi_domain_info = {
+	.ops			= &xen_pci_msi_domain_ops,
+};
+
+/*
+ * This irq domain is a blatant violation of the irq domain design, but
+ * distangling XEN into real irq domains is not a job for mere mortals with
+ * limited XENology. But it's the least dangerous way for a mere mortal to
+ * get rid of the arch_*_msi_irqs() hackery in order to store the irq
+ * domain pointer in struct device. This irq domain wrappery allows to do
+ * that without breaking XEN terminally.
+ */
+static __init struct irq_domain *xen_create_pci_msi_domain(void)
+{
+	struct irq_domain *d = NULL;
+	struct fwnode_handle *fn;
+
+	fn = irq_domain_alloc_named_fwnode("XEN-MSI");
+	if (fn)
+		d = msi_create_irq_domain(fn, &xen_pci_msi_domain_info, NULL);
+
+	/* FIXME: No idea how to survive if this fails */
+	BUG_ON(!d);
+
+	return d;
+}
+
+static __init void xen_setup_pci_msi(void)
+{
+	if (xen_pv_domain()) {
+		if (xen_initial_domain()) {
+			xen_msi_ops.setup_msi_irqs = xen_initdom_setup_msi_irqs;
+			x86_msi.restore_msi_irqs = xen_initdom_restore_msi_irqs;
+		} else {
+			xen_msi_ops.setup_msi_irqs = xen_setup_msi_irqs;
+		}
+		xen_msi_ops.teardown_msi_irqs = xen_pv_teardown_msi_irqs;
+	} else if (xen_hvm_domain()) {
+		xen_msi_ops.setup_msi_irqs = xen_hvm_setup_msi_irqs;
+		xen_msi_ops.teardown_msi_irqs = xen_teardown_msi_irqs;
+	} else {
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	/*
+	 * Override the PCI/MSI irq domain init function. No point
+	 * in allocating the native domain and never use it.
+	 */
+	x86_init.irqs.create_pci_msi_domain = xen_create_pci_msi_domain;
+	/*
+	 * With XEN PIRQ/Eventchannels in use PCI/MSI[-X] masking is solely
+	 * controlled by the hypervisor.
+	 */
+	pci_msi_ignore_mask = 1;
+}
+
+#else /* CONFIG_PCI_MSI */
+static inline void xen_setup_pci_msi(void) { }
+#endif /* CONFIG_PCI_MSI */
+
+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;
+
+	/* Keep ACPI out of the picture */
+	acpi_noirq_set();
+
+	xen_setup_pci_msi();
+	return 0;
+}
+
+#ifdef CONFIG_PCI_MSI
+static void __init xen_hvm_msi_init(void)
+{
+	if (!disable_apic) {
+		/*
+		 * If hardware supports (x2)APIC virtualization (as indicated
+		 * by hypervisor's leaf 4) then we don't need to use pirqs/
+		 * event channels for MSI handling and instead use regular
+		 * APIC processing
+		 */
+		uint32_t eax = cpuid_eax(xen_cpuid_base() + 4);
+
+		if (((eax & XEN_HVM_CPUID_X2APIC_VIRT) && x2apic_mode) ||
+		    ((eax & XEN_HVM_CPUID_APIC_ACCESS_VIRT) && boot_cpu_has(X86_FEATURE_APIC)))
+			return;
+	}
+	xen_setup_pci_msi();
+}
+#endif
+
+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;
+	__acpi_unregister_gsi = NULL;
+#endif
+
+#ifdef CONFIG_PCI_MSI
+	/*
+	 * We need to wait until after x2apic is initialized
+	 * before we can set MSI IRQ ops.
+	 */
+	x86_platform.apic_post_init = xen_hvm_msi_init;
+#endif
+	return 0;
+}
+
+#ifdef CONFIG_XEN_DOM0
+int __init pci_xen_initial_domain(void)
+{
+	int irq;
+
+	xen_setup_pci_msi();
+	__acpi_register_gsi = acpi_register_gsi_xen;
+	__acpi_unregister_gsi = NULL;
+	/*
+	 * Pre-allocate the legacy IRQs.  Use NR_LEGACY_IRQS here
+	 * because we don't have a PIC and thus nr_legacy_irqs() is zero.
+	 */
+	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,
+			trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE,
+			true /* Map GSI to PIRQ */);
+	}
+	if (0 == nr_ioapics) {
+		for (irq = 0; irq < nr_legacy_irqs(); 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