Merge tag 'for-linus-5.16b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:

 - a series to speed up the boot of Xen PV guests

 - some cleanups in Xen related code

 - replacement of license texts with the appropriate SPDX headers and
   fixing of wrong SPDX headers in Xen header files

 - a small series making paravirtualized interrupt masking much simpler
   and at the same time removing complaints of objtool

 - a fix for Xen ballooning hogging workqueues for too long

 - enablement of the Xen pciback driver for Arm

 - some further small fixes/enhancements

* tag 'for-linus-5.16b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (22 commits)
  xen/balloon: fix unused-variable warning
  xen/balloon: rename alloc/free_xenballooned_pages
  xen/balloon: add late_initcall_sync() for initial ballooning done
  x86/xen: remove 32-bit awareness from startup_xen
  xen: remove highmem remnants
  xen: allow pv-only hypercalls only with CONFIG_XEN_PV
  x86/xen: remove 32-bit pv leftovers
  xen-pciback: allow compiling on other archs than x86
  x86/xen: switch initial pvops IRQ functions to dummy ones
  x86/xen: remove xen_have_vcpu_info_placement flag
  x86/pvh: add prototype for xen_pvh_init()
  xen: Fix implicit type conversion
  xen: fix wrong SPDX headers of Xen related headers
  xen/pvcalls-back: Remove redundant 'flush_workqueue()' calls
  x86/xen: Remove redundant irq_enter/exit() invocations
  xen-pciback: Fix return in pm_ctrl_init()
  xen/x86: restrict PV Dom0 identity mapping
  xen/x86: there's no highmem anymore in PV mode
  xen/x86: adjust handling of the L3 user vsyscall special page table
  xen/x86: adjust xen_set_fixmap()
  ...

13 files changed, 219 insertions, 63 deletions

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 1b2c3aca6887..a1b11c62da9e 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -181,10 +181,34 @@ config SWIOTLB_XEN
 	select DMA_OPS
 	select SWIOTLB
 
+config XEN_PCI_STUB
+	bool
+
+config XEN_PCIDEV_STUB
+	tristate "Xen PCI-device stub driver"
+	depends on PCI && !X86 && XEN
+	depends on XEN_BACKEND
+	select XEN_PCI_STUB
+	default m
+	help
+	  The PCI device stub driver provides limited version of the PCI
+	  device backend driver without para-virtualized support for guests.
+	  If you select this to be a module, you will need to make sure no
+	  other driver has bound to the device(s) you want to make visible to
+	  other guests.
+
+	  The "hide" parameter (only applicable if backend driver is compiled
+	  into the kernel) allows you to bind the PCI devices to this module
+	  from the default device drivers. The argument is the list of PCI BDFs:
+	  xen-pciback.hide=(03:00.0)(04:00.0)
+
+	  If in doubt, say m.
+
 config XEN_PCIDEV_BACKEND
 	tristate "Xen PCI-device backend driver"
 	depends on PCI && X86 && XEN
 	depends on XEN_BACKEND
+	select XEN_PCI_STUB
 	default m
 	help
 	  The PCI device backend driver allows the kernel to export arbitrary
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 3434593455b2..5aae66e638a7 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -24,7 +24,7 @@ obj-$(CONFIG_XEN_SYS_HYPERVISOR)	+= sys-hypervisor.o
 obj-$(CONFIG_XEN_PVHVM_GUEST)		+= platform-pci.o
 obj-$(CONFIG_SWIOTLB_XEN)		+= swiotlb-xen.o
 obj-$(CONFIG_XEN_MCE_LOG)		+= mcelog.o
-obj-$(CONFIG_XEN_PCIDEV_BACKEND)	+= xen-pciback/
+obj-$(CONFIG_XEN_PCI_STUB)	        += xen-pciback/
 obj-$(CONFIG_XEN_PRIVCMD)		+= xen-privcmd.o
 obj-$(CONFIG_XEN_ACPI_PROCESSOR)	+= xen-acpi-processor.o
 obj-$(CONFIG_XEN_EFI)			+= efi.o
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 3a50f097ed3e..ba2ea11e0d3d 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -58,6 +58,7 @@
 #include <linux/percpu-defs.h>
 #include <linux/slab.h>
 #include <linux/sysctl.h>
+#include <linux/moduleparam.h>
 
 #include <asm/page.h>
 #include <asm/tlb.h>
@@ -73,9 +74,14 @@
 #include <xen/page.h>
 #include <xen/mem-reservation.h>
 
-static int xen_hotplug_unpopulated;
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "xen."
+
+static uint __read_mostly balloon_boot_timeout = 180;
+module_param(balloon_boot_timeout, uint, 0444);
 
 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+static int xen_hotplug_unpopulated;
 
 static struct ctl_table balloon_table[] = {
 	{
@@ -108,6 +114,8 @@ static struct ctl_table xen_root[] = {
 	{ }
 };
 
+#else
+#define xen_hotplug_unpopulated 0
 #endif
 
 /*
@@ -125,12 +133,12 @@ static struct ctl_table xen_root[] = {
  * BP_ECANCELED: error, balloon operation canceled.
  */
 
-enum bp_state {
+static enum bp_state {
 	BP_DONE,
 	BP_WAIT,
 	BP_EAGAIN,
 	BP_ECANCELED
-};
+} balloon_state = BP_DONE;
 
 /* Main waiting point for xen-balloon thread. */
 static DECLARE_WAIT_QUEUE_HEAD(balloon_thread_wq);
@@ -199,18 +207,15 @@ static struct page *balloon_next_page(struct page *page)
 	return list_entry(next, struct page, lru);
 }
 
-static enum bp_state update_schedule(enum bp_state state)
+static void update_schedule(void)
 {
-	if (state == BP_WAIT)
-		return BP_WAIT;
-
-	if (state == BP_ECANCELED)
-		return BP_ECANCELED;
+	if (balloon_state == BP_WAIT || balloon_state == BP_ECANCELED)
+		return;
 
-	if (state == BP_DONE) {
+	if (balloon_state == BP_DONE) {
 		balloon_stats.schedule_delay = 1;
 		balloon_stats.retry_count = 1;
-		return BP_DONE;
+		return;
 	}
 
 	++balloon_stats.retry_count;
@@ -219,7 +224,8 @@ static enum bp_state update_schedule(enum bp_state state)
 			balloon_stats.retry_count > balloon_stats.max_retry_count) {
 		balloon_stats.schedule_delay = 1;
 		balloon_stats.retry_count = 1;
-		return BP_ECANCELED;
+		balloon_state = BP_ECANCELED;
+		return;
 	}
 
 	balloon_stats.schedule_delay <<= 1;
@@ -227,7 +233,7 @@ static enum bp_state update_schedule(enum bp_state state)
 	if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay)
 		balloon_stats.schedule_delay = balloon_stats.max_schedule_delay;
 
-	return BP_EAGAIN;
+	balloon_state = BP_EAGAIN;
 }
 
 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
@@ -494,9 +500,9 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
  * Stop waiting if either state is BP_DONE and ballooning action is
  * needed, or if the credit has changed while state is not BP_DONE.
  */
-static bool balloon_thread_cond(enum bp_state state, long credit)
+static bool balloon_thread_cond(long credit)
 {
-	if (state == BP_DONE)
+	if (balloon_state == BP_DONE)
 		credit = 0;
 
 	return current_credit() != credit || kthread_should_stop();
@@ -510,13 +516,12 @@ static bool balloon_thread_cond(enum bp_state state, long credit)
  */
 static int balloon_thread(void *unused)
 {
-	enum bp_state state = BP_DONE;
 	long credit;
 	unsigned long timeout;
 
 	set_freezable();
 	for (;;) {
-		switch (state) {
+		switch (balloon_state) {
 		case BP_DONE:
 		case BP_ECANCELED:
 			timeout = 3600 * HZ;
@@ -532,7 +537,7 @@ static int balloon_thread(void *unused)
 		credit = current_credit();
 
 		wait_event_freezable_timeout(balloon_thread_wq,
-			balloon_thread_cond(state, credit), timeout);
+			balloon_thread_cond(credit), timeout);
 
 		if (kthread_should_stop())
 			return 0;
@@ -543,22 +548,23 @@ static int balloon_thread(void *unused)
 
 		if (credit > 0) {
 			if (balloon_is_inflated())
-				state = increase_reservation(credit);
+				balloon_state = increase_reservation(credit);
 			else
-				state = reserve_additional_memory();
+				balloon_state = reserve_additional_memory();
 		}
 
 		if (credit < 0) {
 			long n_pages;
 
 			n_pages = min(-credit, si_mem_available());
-			state = decrease_reservation(n_pages, GFP_BALLOON);
-			if (state == BP_DONE && n_pages != -credit &&
+			balloon_state = decrease_reservation(n_pages,
+							     GFP_BALLOON);
+			if (balloon_state == BP_DONE && n_pages != -credit &&
 			    n_pages < totalreserve_pages)
-				state = BP_EAGAIN;
+				balloon_state = BP_EAGAIN;
 		}
 
-		state = update_schedule(state);
+		update_schedule();
 
 		mutex_unlock(&balloon_mutex);
 
@@ -575,7 +581,8 @@ void balloon_set_new_target(unsigned long target)
 }
 EXPORT_SYMBOL_GPL(balloon_set_new_target);
 
-static int add_ballooned_pages(int nr_pages)
+#ifndef CONFIG_XEN_UNPOPULATED_ALLOC
+static int add_ballooned_pages(unsigned int nr_pages)
 {
 	enum bp_state st;
 
@@ -603,14 +610,14 @@ static int add_ballooned_pages(int nr_pages)
 }
 
 /**
- * alloc_xenballooned_pages - get pages that have been ballooned out
+ * xen_alloc_unpopulated_pages - get pages that have been ballooned out
  * @nr_pages: Number of pages to get
  * @pages: pages returned
  * @return 0 on success, error otherwise
  */
-int alloc_xenballooned_pages(int nr_pages, struct page **pages)
+int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)
 {
-	int pgno = 0;
+	unsigned int pgno = 0;
 	struct page *page;
 	int ret;
 
@@ -645,7 +652,7 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
 	return 0;
  out_undo:
 	mutex_unlock(&balloon_mutex);
-	free_xenballooned_pages(pgno, pages);
+	xen_free_unpopulated_pages(pgno, pages);
 	/*
 	 * NB: free_xenballooned_pages will only subtract pgno pages, but since
 	 * target_unpopulated is incremented with nr_pages at the start we need
@@ -654,16 +661,16 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
 	balloon_stats.target_unpopulated -= nr_pages - pgno;
 	return ret;
 }
-EXPORT_SYMBOL(alloc_xenballooned_pages);
+EXPORT_SYMBOL(xen_alloc_unpopulated_pages);
 
 /**
- * free_xenballooned_pages - return pages retrieved with get_ballooned_pages
+ * xen_free_unpopulated_pages - return pages retrieved with get_ballooned_pages
  * @nr_pages: Number of pages
  * @pages: pages to return
  */
-void free_xenballooned_pages(int nr_pages, struct page **pages)
+void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages)
 {
-	int i;
+	unsigned int i;
 
 	mutex_lock(&balloon_mutex);
 
@@ -680,9 +687,9 @@ void free_xenballooned_pages(int nr_pages, struct page **pages)
 
 	mutex_unlock(&balloon_mutex);
 }
-EXPORT_SYMBOL(free_xenballooned_pages);
+EXPORT_SYMBOL(xen_free_unpopulated_pages);
 
-#if defined(CONFIG_XEN_PV) && !defined(CONFIG_XEN_UNPOPULATED_ALLOC)
+#if defined(CONFIG_XEN_PV)
 static void __init balloon_add_region(unsigned long start_pfn,
 				      unsigned long pages)
 {
@@ -705,6 +712,7 @@ static void __init balloon_add_region(unsigned long start_pfn,
 	balloon_stats.total_pages += extra_pfn_end - start_pfn;
 }
 #endif
+#endif
 
 static int __init balloon_init(void)
 {
@@ -765,3 +773,38 @@ static int __init balloon_init(void)
 	return 0;
 }
 subsys_initcall(balloon_init);
+
+static int __init balloon_wait_finish(void)
+{
+	long credit, last_credit = 0;
+	unsigned long last_changed = 0;
+
+	if (!xen_domain())
+		return -ENODEV;
+
+	/* PV guests don't need to wait. */
+	if (xen_pv_domain() || !current_credit())
+		return 0;
+
+	pr_notice("Waiting for initial ballooning down having finished.\n");
+
+	while ((credit = current_credit()) < 0) {
+		if (credit != last_credit) {
+			last_changed = jiffies;
+			last_credit = credit;
+		}
+		if (balloon_state == BP_ECANCELED) {
+			pr_warn_once("Initial ballooning failed, %ld pages need to be freed.\n",
+				     -credit);
+			if (jiffies - last_changed >= HZ * balloon_boot_timeout)
+				panic("Initial ballooning failed!\n");
+		}
+
+		schedule_timeout_interruptible(HZ / 10);
+	}
+
+	pr_notice("Initial ballooning down finished.\n");
+
+	return 0;
+}
+late_initcall_sync(balloon_wait_finish);
diff --git a/drivers/xen/mem-reservation.c b/drivers/xen/mem-reservation.c
index 3782cf070338..24648836e0d4 100644
--- a/drivers/xen/mem-reservation.c
+++ b/drivers/xen/mem-reservation.c
@@ -35,6 +35,7 @@ void __xenmem_reservation_va_mapping_update(unsigned long count,
 	for (i = 0; i < count; i++) {
 		struct page *page = pages[i];
 		unsigned long pfn = page_to_pfn(page);
+		int ret;
 
 		BUG_ON(!page);
 
@@ -46,16 +47,10 @@ void __xenmem_reservation_va_mapping_update(unsigned long count,
 
 		set_phys_to_machine(pfn, frames[i]);
 
-		/* Link back into the page tables if not highmem. */
-		if (!PageHighMem(page)) {
-			int ret;
-
-			ret = HYPERVISOR_update_va_mapping(
-					(unsigned long)__va(pfn << PAGE_SHIFT),
-					mfn_pte(frames[i], PAGE_KERNEL),
-					0);
-			BUG_ON(ret);
-		}
+		ret = HYPERVISOR_update_va_mapping(
+				(unsigned long)__va(pfn << PAGE_SHIFT),
+				mfn_pte(frames[i], PAGE_KERNEL), 0);
+		BUG_ON(ret);
 	}
 }
 EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_update);
@@ -68,6 +63,7 @@ void __xenmem_reservation_va_mapping_reset(unsigned long count,
 	for (i = 0; i < count; i++) {
 		struct page *page = pages[i];
 		unsigned long pfn = page_to_pfn(page);
+		int ret;
 
 		/*
 		 * We don't support PV MMU when Linux and Xen are using
@@ -75,14 +71,11 @@ void __xenmem_reservation_va_mapping_reset(unsigned long count,
 		 */
 		BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
 
-		if (!PageHighMem(page)) {
-			int ret;
+		ret = HYPERVISOR_update_va_mapping(
+				(unsigned long)__va(pfn << PAGE_SHIFT),
+				__pte_ma(0), 0);
+		BUG_ON(ret);
 
-			ret = HYPERVISOR_update_va_mapping(
-					(unsigned long)__va(pfn << PAGE_SHIFT),
-					__pte_ma(0), 0);
-			BUG_ON(ret);
-		}
 		__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 	}
 }
diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c
index 224df03ce42e..2c890f4f2cbc 100644
--- a/drivers/xen/pci.c
+++ b/drivers/xen/pci.c
@@ -8,6 +8,7 @@
 #include <linux/pci.h>
 #include <linux/acpi.h>
 #include <linux/pci-acpi.h>
+#include <xen/pci.h>
 #include <xen/xen.h>
 #include <xen/interface/physdev.h>
 #include <xen/interface/xen.h>
@@ -254,3 +255,78 @@ static int xen_mcfg_late(void)
 	return 0;
 }
 #endif
+
+#ifdef CONFIG_XEN_DOM0
+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
diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index b47fd8435061..d6f945fd4147 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -465,7 +465,6 @@ static int pvcalls_back_release_passive(struct xenbus_device *dev,
 		write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
 	}
 	sock_release(mappass->sock);
-	flush_workqueue(mappass->wq);
 	destroy_workqueue(mappass->wq);
 	kfree(mappass);
 
diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c
index df7cab870be5..9cb61db67efd 100644
--- a/drivers/xen/xen-acpi-processor.c
+++ b/drivers/xen/xen-acpi-processor.c
@@ -450,7 +450,7 @@ static struct acpi_processor_performance __percpu *acpi_perf_data;
 
 static void free_acpi_perf_data(void)
 {
-	unsigned int i;
+	int i;
 
 	/* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
 	for_each_possible_cpu(i)
@@ -462,7 +462,7 @@ static void free_acpi_perf_data(void)
 static int xen_upload_processor_pm_data(void)
 {
 	struct acpi_processor *pr_backup = NULL;
-	unsigned int i;
+	int i;
 	int rc = 0;
 
 	pr_info("Uploading Xen processor PM info\n");
@@ -518,7 +518,7 @@ static struct syscore_ops xap_syscore_ops = {
 
 static int __init xen_acpi_processor_init(void)
 {
-	unsigned int i;
+	int i;
 	int rc;
 
 	if (!xen_initial_domain())
diff --git a/drivers/xen/xen-pciback/Makefile b/drivers/xen/xen-pciback/Makefile
index e8d981d43235..d63df09de81c 100644
--- a/drivers/xen/xen-pciback/Makefile
+++ b/drivers/xen/xen-pciback/Makefile
@@ -1,5 +1,12 @@
 # SPDX-License-Identifier: GPL-2.0
+
+# N.B. The below cannot be expressed with a single line using
+# CONFIG_XEN_PCI_STUB as it always remains in "y" state,
+# thus preventing the driver to be built as a module.
+# Please note, that CONFIG_XEN_PCIDEV_BACKEND and
+# CONFIG_XEN_PCIDEV_STUB are mutually exclusive.
 obj-$(CONFIG_XEN_PCIDEV_BACKEND) += xen-pciback.o
+obj-$(CONFIG_XEN_PCIDEV_STUB) += xen-pciback.o
 
 xen-pciback-y := pci_stub.o pciback_ops.o xenbus.o
 xen-pciback-y += conf_space.o conf_space_header.o \
diff --git a/drivers/xen/xen-pciback/conf_space_capability.c b/drivers/xen/xen-pciback/conf_space_capability.c
index 22f13abbe913..5e53b4817f16 100644
--- a/drivers/xen/xen-pciback/conf_space_capability.c
+++ b/drivers/xen/xen-pciback/conf_space_capability.c
@@ -160,7 +160,7 @@ static void *pm_ctrl_init(struct pci_dev *dev, int offset)
 	}
 
 out:
-	return ERR_PTR(err);
+	return err ? ERR_PTR(err) : NULL;
 }
 
 static const struct config_field caplist_pm[] = {
diff --git a/drivers/xen/xen-pciback/conf_space_header.c b/drivers/xen/xen-pciback/conf_space_header.c
index ac45cdc38e85..981435103af1 100644
--- a/drivers/xen/xen-pciback/conf_space_header.c
+++ b/drivers/xen/xen-pciback/conf_space_header.c
@@ -236,8 +236,12 @@ static void *bar_init(struct pci_dev *dev, int offset)
 	else {
 		pos = (offset - PCI_BASE_ADDRESS_0) / 4;
 		if (pos && (res[pos - 1].flags & IORESOURCE_MEM_64)) {
-			bar->val = res[pos - 1].start >> 32;
-			bar->len_val = -resource_size(&res[pos - 1]) >> 32;
+			/*
+			 * Use ">> 16 >> 16" instead of direct ">> 32" shift
+			 * to avoid warnings on 32-bit architectures.
+			 */
+			bar->val = res[pos - 1].start >> 16 >> 16;
+			bar->len_val = -resource_size(&res[pos - 1]) >> 16 >> 16;
 			return bar;
 		}
 	}
diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
index f8e4faa96ad6..bba527620507 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -19,7 +19,8 @@
 #include <linux/sched.h>
 #include <linux/atomic.h>
 #include <xen/events.h>
-#include <asm/xen/pci.h>
+#include <xen/pci.h>
+#include <xen/xen.h>
 #include <asm/xen/hypervisor.h>
 #include <xen/interface/physdev.h>
 #include "pciback.h"
diff --git a/drivers/xen/xen-pciback/pciback.h b/drivers/xen/xen-pciback/pciback.h
index 95e28ee48d52..9a64196e831d 100644
--- a/drivers/xen/xen-pciback/pciback.h
+++ b/drivers/xen/xen-pciback/pciback.h
@@ -71,6 +71,11 @@ struct pci_dev *pcistub_get_pci_dev(struct xen_pcibk_device *pdev,
 				    struct pci_dev *dev);
 void pcistub_put_pci_dev(struct pci_dev *dev);
 
+static inline bool xen_pcibk_pv_support(void)
+{
+	return IS_ENABLED(CONFIG_XEN_PCIDEV_BACKEND);
+}
+
 /* Ensure a device is turned off or reset */
 void xen_pcibk_reset_device(struct pci_dev *pdev);
 
diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index c09c7ebd6968..bde63ef677b8 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -14,7 +14,7 @@
 #include <linux/workqueue.h>
 #include <xen/xenbus.h>
 #include <xen/events.h>
-#include <asm/xen/pci.h>
+#include <xen/pci.h>
 #include "pciback.h"
 
 #define INVALID_EVTCHN_IRQ  (-1)
@@ -743,6 +743,9 @@ const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
 
 int __init xen_pcibk_xenbus_register(void)
 {
+	if (!xen_pcibk_pv_support())
+		return 0;
+
 	xen_pcibk_backend = &xen_pcibk_vpci_backend;
 	if (passthrough)
 		xen_pcibk_backend = &xen_pcibk_passthrough_backend;
@@ -752,5 +755,6 @@ int __init xen_pcibk_xenbus_register(void)
 
 void __exit xen_pcibk_xenbus_unregister(void)
 {
-	xenbus_unregister_driver(&xen_pcibk_driver);
+	if (xen_pcibk_pv_support())
+		xenbus_unregister_driver(&xen_pcibk_driver);
 }