Merge tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from David Vrabel:
 "Xen features and cleanups for 4.2-rc0:

   - add "make xenconfig" to assist in generating configs for Xen guests

   - preparatory cleanups necessary for supporting 64 KiB pages in ARM
     guests

   - automatically use hvc0 as the default console in ARM guests"

* tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  block/xen-blkback: s/nr_pages/nr_segs/
  block/xen-blkfront: Remove invalid comment
  block/xen-blkfront: Remove unused macro MAXIMUM_OUTSTANDING_BLOCK_REQS
  arm/xen: Drop duplicate define mfn_to_virt
  xen/grant-table: Remove unused macro SPP
  xen/xenbus: client: Fix call of virt_to_mfn in xenbus_grant_ring
  xen: Include xen/page.h rather than asm/xen/page.h
  kconfig: add xenconfig defconfig helper
  kconfig: clarify kvmconfig is for kvm
  xen/pcifront: Remove usage of struct timeval
  xen/tmem: use BUILD_BUG_ON() in favor of BUG_ON()
  hvc_xen: avoid uninitialized variable warning
  xenbus: avoid uninitialized variable warning
  xen/arm: allow console=hvc0 to be omitted for guests
  arm,arm64/xen: move Xen initialization earlier
  arm/xen: Correctly check if the event channel interrupt is present

25 files changed, 157 insertions, 59 deletions

diff --git a/arch/arm/include/asm/xen/hypervisor.h b/arch/arm/include/asm/xen/hypervisor.h
index 1317ee40f4df..04ff8e7b37df 100644
--- a/arch/arm/include/asm/xen/hypervisor.h
+++ b/arch/arm/include/asm/xen/hypervisor.h
@@ -1,6 +1,8 @@
 #ifndef _ASM_ARM_XEN_HYPERVISOR_H
 #define _ASM_ARM_XEN_HYPERVISOR_H
 
+#include <linux/init.h>
+
 extern struct shared_info *HYPERVISOR_shared_info;
 extern struct start_info *xen_start_info;
 
@@ -18,4 +20,10 @@ static inline enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
 
 extern struct dma_map_ops *xen_dma_ops;
 
+#ifdef CONFIG_XEN
+void __init xen_early_init(void);
+#else
+static inline void xen_early_init(void) { return; }
+#endif
+
 #endif /* _ASM_ARM_XEN_HYPERVISOR_H */
diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
index 0b579b2f4e0e..1bee8ca12494 100644
--- a/arch/arm/include/asm/xen/page.h
+++ b/arch/arm/include/asm/xen/page.h
@@ -12,7 +12,6 @@
 #include <xen/interface/grant_table.h>
 
 #define phys_to_machine_mapping_valid(pfn) (1)
-#define mfn_to_virt(m)                  (__va(mfn_to_pfn(m) << PAGE_SHIFT))
 
 #define pte_mfn     pte_pfn
 #define mfn_pte     pfn_pte
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index e6d8c7658ffd..36c18b73c1f4 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -46,6 +46,7 @@
 #include <asm/cacheflush.h>
 #include <asm/cachetype.h>
 #include <asm/tlbflush.h>
+#include <asm/xen/hypervisor.h>
 
 #include <asm/prom.h>
 #include <asm/mach/arch.h>
@@ -972,6 +973,7 @@ void __init setup_arch(char **cmdline_p)
 
         arm_dt_init_cpu_maps();
         psci_init();
+        xen_early_init();
 #ifdef CONFIG_SMP
         if (is_smp()) {
                 if (!mdesc->smp_init || !mdesc->smp_init()) {
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 7d0f07020c80..6c09cc440a2b 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -24,6 +24,7 @@
 #include <linux/cpuidle.h>
 #include <linux/cpufreq.h>
 #include <linux/cpu.h>
+#include <linux/console.h>
 
 #include <linux/mm.h>
 
@@ -51,7 +52,9 @@ EXPORT_SYMBOL_GPL(xen_have_vector_callback);
 int xen_platform_pci_unplug = XEN_UNPLUG_ALL;
 EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
 
-static __read_mostly int xen_events_irq = -1;
+static __read_mostly unsigned int xen_events_irq;
+
+static __initdata struct device_node *xen_node;
 
 int xen_remap_domain_mfn_array(struct vm_area_struct *vma,
                                unsigned long addr,
@@ -150,40 +153,28 @@ static irqreturn_t xen_arm_callback(int irq, void *arg)
  * documentation of the Xen Device Tree format.
  */
 #define GRANT_TABLE_PHYSADDR 0
-static int __init xen_guest_init(void)
+void __init xen_early_init(void)
 {
-        struct xen_add_to_physmap xatp;
-        static struct shared_info *shared_info_page = 0;
-        struct device_node *node;
         int len;
         const char *s = NULL;
         const char *version = NULL;
         const char *xen_prefix = "xen,xen-";
-        struct resource res;
-        phys_addr_t grant_frames;
 
-        node = of_find_compatible_node(NULL, NULL, "xen,xen");
-        if (!node) {
+        xen_node = of_find_compatible_node(NULL, NULL, "xen,xen");
+        if (!xen_node) {
                 pr_debug("No Xen support\n");
-                return 0;
+                return;
         }
-        s = of_get_property(node, "compatible", &len);
+        s = of_get_property(xen_node, "compatible", &len);
         if (strlen(xen_prefix) + 3  < len &&
                         !strncmp(xen_prefix, s, strlen(xen_prefix)))
                 version = s + strlen(xen_prefix);
         if (version == NULL) {
                 pr_debug("Xen version not found\n");
-                return 0;
+                return;
         }
-        if (of_address_to_resource(node, GRANT_TABLE_PHYSADDR, &res))
-                return 0;
-        grant_frames = res.start;
-        xen_events_irq = irq_of_parse_and_map(node, 0);
-        pr_info("Xen %s support found, events_irq=%d gnttab_frame=%pa\n",
-                        version, xen_events_irq, &grant_frames);
 
-        if (xen_events_irq < 0)
-                return -ENODEV;
+        pr_info("Xen %s support found\n", version);
 
         xen_domain_type = XEN_HVM_DOMAIN;
 
@@ -194,9 +185,34 @@ static int __init xen_guest_init(void)
         else
                 xen_start_info->flags &= ~(SIF_INITDOMAIN|SIF_PRIVILEGED);
 
-        if (!shared_info_page)
-                shared_info_page = (struct shared_info *)
-                        get_zeroed_page(GFP_KERNEL);
+        if (!console_set_on_cmdline && !xen_initial_domain())
+                add_preferred_console("hvc", 0, NULL);
+}
+
+static int __init xen_guest_init(void)
+{
+        struct xen_add_to_physmap xatp;
+        struct shared_info *shared_info_page = NULL;
+        struct resource res;
+        phys_addr_t grant_frames;
+
+        if (!xen_domain())
+                return 0;
+
+        if (of_address_to_resource(xen_node, GRANT_TABLE_PHYSADDR, &res)) {
+                pr_err("Xen grant table base address not found\n");
+                return -ENODEV;
+        }
+        grant_frames = res.start;
+
+        xen_events_irq = irq_of_parse_and_map(xen_node, 0);
+        if (!xen_events_irq) {
+                pr_err("Xen event channel interrupt not found\n");
+                return -ENODEV;
+        }
+
+        shared_info_page = (struct shared_info *)get_zeroed_page(GFP_KERNEL);
+
         if (!shared_info_page) {
                 pr_err("not enough memory\n");
                 return -ENOMEM;
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 498325074a06..03e75fef15b8 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -15,10 +15,10 @@
 #include <xen/xen.h>
 #include <xen/interface/grant_table.h>
 #include <xen/interface/memory.h>
+#include <xen/page.h>
 #include <xen/swiotlb-xen.h>
 
 #include <asm/cacheflush.h>
-#include <asm/xen/page.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/interface.h>
 
diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c
index cb7a14c5cd69..887596c67b12 100644
--- a/arch/arm/xen/p2m.c
+++ b/arch/arm/xen/p2m.c
@@ -10,10 +10,10 @@
 
 #include <xen/xen.h>
 #include <xen/interface/memory.h>
+#include <xen/page.h>
 #include <xen/swiotlb-xen.h>
 
 #include <asm/cacheflush.h>
-#include <asm/xen/page.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/interface.h>
 
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index ffd3970721bf..f3067d4d4e35 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -64,6 +64,7 @@
 #include <asm/psci.h>
 #include <asm/efi.h>
 #include <asm/virt.h>
+#include <asm/xen/hypervisor.h>
 
 unsigned long elf_hwcap __read_mostly;
 EXPORT_SYMBOL_GPL(elf_hwcap);
@@ -401,6 +402,7 @@ void __init setup_arch(char **cmdline_p)
         } else {
                 psci_acpi_init();
         }
+        xen_early_init();
 
         cpu_read_bootcpu_ops();
 #ifdef CONFIG_SMP
diff --git a/arch/x86/configs/xen.config b/arch/x86/configs/xen.config
new file mode 100644
index 000000000000..d9fc7139fd46
--- /dev/null
+++ b/arch/x86/configs/xen.config
@@ -0,0 +1,28 @@
+# global x86 required specific stuff
+# On 32-bit HIGHMEM4G is not allowed
+CONFIG_HIGHMEM64G=y
+CONFIG_64BIT=y
+
+# These enable us to allow some of the
+# not so generic stuff below
+CONFIG_HYPERVISOR_GUEST=y
+CONFIG_PCI=y
+CONFIG_PCI_MSI=y
+CONFIG_X86_MCE=y
+CONFIG_ACPI_PROCESSOR=y
+CONFIG_CPU_FREQ=y
+
+# x86 xen specific config options
+CONFIG_XEN_PVH=y
+CONFIG_XEN_MAX_DOMAIN_MEMORY=500
+CONFIG_XEN_SAVE_RESTORE=y
+# CONFIG_XEN_DEBUG_FS is not set
+CONFIG_XEN_MCE_LOG=y
+CONFIG_XEN_ACPI_PROCESSOR=m
+# x86 specific backend drivers
+CONFIG_XEN_PCIDEV_BACKEND=m
+# x86 specific frontend drivers
+CONFIG_XEN_PCIDEV_FRONTEND=m
+# depends on MEMORY_HOTPLUG, arm64 doesn't enable this yet,
+# move to generic config if it ever does.
+CONFIG_XEN_BALLOON_MEMORY_HOTPLUG=y
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 2126842fb6e8..ced96777b677 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -736,7 +736,7 @@ static void xen_blkbk_unmap_and_respond(struct pending_req *req)
         struct grant_page **pages = req->segments;
         unsigned int invcount;
 
-        invcount = xen_blkbk_unmap_prepare(blkif, pages, req->nr_pages,
+        invcount = xen_blkbk_unmap_prepare(blkif, pages, req->nr_segs,
                                            req->unmap, req->unmap_pages);
 
         work->data = req;
@@ -922,7 +922,7 @@ static int xen_blkbk_map_seg(struct pending_req *pending_req)
         int rc;
 
         rc = xen_blkbk_map(pending_req->blkif, pending_req->segments,
-                           pending_req->nr_pages,
+                           pending_req->nr_segs,
                            (pending_req->operation != BLKIF_OP_READ));
 
         return rc;
@@ -938,7 +938,7 @@ static int xen_blkbk_parse_indirect(struct blkif_request *req,
         int indirect_grefs, rc, n, nseg, i;
         struct blkif_request_segment *segments = NULL;
 
-        nseg = pending_req->nr_pages;
+        nseg = pending_req->nr_segs;
         indirect_grefs = INDIRECT_PAGES(nseg);
         BUG_ON(indirect_grefs > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
 
@@ -1258,7 +1258,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
         pending_req->id        = req->u.rw.id;
         pending_req->operation = req_operation;
         pending_req->status    = BLKIF_RSP_OKAY;
-        pending_req->nr_pages  = nseg;
+        pending_req->nr_segs   = nseg;
 
         if (req->operation != BLKIF_OP_INDIRECT) {
                 preq.dev               = req->u.rw.handle;
@@ -1379,7 +1379,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
 
  fail_flush:
         xen_blkbk_unmap(blkif, pending_req->segments,
-                        pending_req->nr_pages);
+                        pending_req->nr_segs);
  fail_response:
         /* Haven't submitted any bio's yet. */
         make_response(blkif, req->u.rw.id, req_operation, BLKIF_RSP_ERROR);
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 8ccc49d01c8e..45a044a53d1e 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -345,7 +345,7 @@ struct grant_page {
 struct pending_req {
         struct xen_blkif        *blkif;
         u64                     id;
-        int                     nr_pages;
+        int                     nr_segs;
         atomic_t                pendcnt;
         unsigned short          operation;
         int                     status;
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index fc770b7d3beb..6d89ed35d80c 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1074,12 +1074,6 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
                 s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
 
         if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
-                /*
-                 * Copy the data received from the backend into the bvec.
-                 * Since bv_offset can be different than 0, and bv_len different
-                 * than PAGE_SIZE, we have to keep track of the current offset,
-                 * to be sure we are copying the data from the right shared page.
-                 */
                 for_each_sg(s->sg, sg, nseg, i) {
                         BUG_ON(sg->offset + sg->length > PAGE_SIZE);
                         shared_data = kmap_atomic(
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 5485f91294e7..880d0d63e872 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -44,9 +44,9 @@
 #include <xen/xen.h>
 #include <xen/events.h>
 #include <xen/interface/memory.h>
+#include <xen/page.h>
 
 #include <asm/xen/hypercall.h>
-#include <asm/xen/page.h>
 
 /* Provide an option to disable split event channels at load time as
  * event channels are limited resource. Split event channels are
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 56d8afd11077..b3e9491bc8ec 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -45,7 +45,6 @@
 #include <linux/slab.h>
 #include <net/ip.h>
 
-#include <asm/xen/page.h>
 #include <xen/xen.h>
 #include <xen/xenbus.h>
 #include <xen/events.h>
diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index 240f38872085..8b7a900cd28b 100644
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -20,6 +20,7 @@
 #include <linux/workqueue.h>
 #include <linux/bitops.h>
 #include <linux/time.h>
+#include <linux/ktime.h>
 #include <xen/platform_pci.h>
 
 #include <asm/xen/swiotlb-xen.h>
@@ -115,7 +116,6 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
         evtchn_port_t port = pdev->evtchn;
         unsigned irq = pdev->irq;
         s64 ns, ns_timeout;
-        struct timeval tv;
 
         spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
 
@@ -132,8 +132,7 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
          * (in the latter case we end up continually re-executing poll() with a
          * timeout in the past). 1s difference gives plenty of slack for error.
          */
-        do_gettimeofday(&tv);
-        ns_timeout = timeval_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
+        ns_timeout = ktime_get_ns() + 2 * (s64)NSEC_PER_SEC;
 
         xen_clear_irq_pending(irq);
 
@@ -141,8 +140,7 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
                         (unsigned long *)&pdev->sh_info->flags)) {
                 xen_poll_irq_timeout(irq, jiffies + 3*HZ);
                 xen_clear_irq_pending(irq);
-                do_gettimeofday(&tv);
-                ns = timeval_to_ns(&tv);
+                ns = ktime_get_ns();
                 if (ns > ns_timeout) {
                         dev_err(&pdev->xdev->dev,
                                 "pciback not responding!!!\n");
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 7a3d146a5f0e..a9d837f83ce8 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -302,7 +302,7 @@ static int xen_initial_domain_console_init(void)
 static void xen_console_update_evtchn(struct xencons_info *info)
 {
         if (xen_hvm_domain()) {
-                uint64_t v;
+                uint64_t v = 0;
                 int err;
 
                 err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 38387950490e..96093ae369a5 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -39,8 +39,8 @@
 #include <asm/irq.h>
 #include <asm/idle.h>
 #include <asm/io_apic.h>
-#include <asm/xen/page.h>
 #include <asm/xen/pci.h>
+#include <xen/page.h>
 #endif
 #include <asm/sync_bitops.h>
 #include <asm/xen/hypercall.h>
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index 417415d738d0..ed673e1acd61 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -44,13 +44,13 @@
 #include <asm/sync_bitops.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
-#include <asm/xen/page.h>
 
 #include <xen/xen.h>
 #include <xen/xen-ops.h>
 #include <xen/events.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/event_channel.h>
+#include <xen/page.h>
 
 #include "events_internal.h"
 
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 89274850741b..67b9163db718 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -41,9 +41,9 @@
 #include <xen/balloon.h>
 #include <xen/gntdev.h>
 #include <xen/events.h>
+#include <xen/page.h>
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
-#include <asm/xen/page.h>
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index b1c7170e5c9e..62f591f8763c 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -138,7 +138,6 @@ static struct gnttab_free_callback *gnttab_free_callback_list;
 static int gnttab_expand(unsigned int req_entries);
 
 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
-#define SPP (PAGE_SIZE / sizeof(grant_status_t))
 
 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
 {
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 9e6a85104a20..d10effee9b9e 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -19,10 +19,10 @@
 #include <xen/grant_table.h>
 #include <xen/events.h>
 #include <xen/hvc-console.h>
+#include <xen/page.h>
 #include <xen/xen-ops.h>
 
 #include <asm/xen/hypercall.h>
-#include <asm/xen/page.h>
 #include <asm/xen/hypervisor.h>
 
 enum shutdown_state {
diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index d88f36754bf7..239738f944ba 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -17,8 +17,8 @@
 
 #include <xen/xen.h>
 #include <xen/interface/xen.h>
+#include <xen/page.h>
 #include <asm/xen/hypercall.h>
-#include <asm/xen/page.h>
 #include <asm/xen/hypervisor.h>
 #include <xen/tmem.h>
 
@@ -389,7 +389,7 @@ static int __init xen_tmem_init(void)
         }
 #endif
 #ifdef CONFIG_CLEANCACHE
-        BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
+        BUILD_BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
         if (tmem_enabled && cleancache) {
                 int err;
 
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 96b2011d25f3..9ad327238ba9 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -37,7 +37,7 @@
 #include <linux/vmalloc.h>
 #include <linux/export.h>
 #include <asm/xen/hypervisor.h>
-#include <asm/xen/page.h>
+#include <xen/page.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/event_channel.h>
 #include <xen/balloon.h>
@@ -379,16 +379,16 @@ int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
         int i, j;
 
         for (i = 0; i < nr_pages; i++) {
-                unsigned long addr = (unsigned long)vaddr +
-                        (PAGE_SIZE * i);
                 err = gnttab_grant_foreign_access(dev->otherend_id,
-                                                  virt_to_mfn(addr), 0);
+                                                  virt_to_mfn(vaddr), 0);
                 if (err < 0) {
                         xenbus_dev_fatal(dev, err,
                                          "granting access to ring page");
                         goto fail;
                 }
                 grefs[i] = err;
+
+                vaddr = vaddr + PAGE_SIZE;
         }
 
         return 0;
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 5390a674b5e3..4308fb3cf7c2 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -742,7 +742,7 @@ static int xenbus_resume_cb(struct notifier_block *nb,
         int err = 0;
 
         if (xen_hvm_domain()) {
-                uint64_t v;
+                uint64_t v = 0;
 
                 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
                 if (!err && v)
diff --git a/kernel/configs/xen.config b/kernel/configs/xen.config
new file mode 100644
index 000000000000..ff756221f112
--- /dev/null
+++ b/kernel/configs/xen.config
@@ -0,0 +1,48 @@
+# global stuff - these enable us to allow some
+# of the not so generic stuff below for xen
+CONFIG_PARAVIRT=y
+CONFIG_NET=y
+CONFIG_NET_CORE=y
+CONFIG_NETDEVICES=y
+CONFIG_BLOCK=y
+CONFIG_WATCHDOG=y
+CONFIG_TARGET_CORE=y
+CONFIG_SCSI=y
+CONFIG_FB=y
+CONFIG_INPUT_MISC=y
+CONFIG_MEMORY_HOTPLUG=y
+CONFIG_TTY=y
+# Technically not required but otherwise produces
+# pretty useless systems starting from allnoconfig
+# You want TCP/IP and ELF binaries right?
+CONFIG_INET=y
+CONFIG_BINFMT_ELF=y
+# generic config
+CONFIG_XEN=y
+CONFIG_XEN_DOM0=y
+# backend drivers
+CONFIG_XEN_BACKEND=y
+CONFIG_XEN_BLKDEV_BACKEND=m
+CONFIG_XEN_NETDEV_BACKEND=m
+CONFIG_HVC_XEN=y
+CONFIG_XEN_WDT=m
+CONFIG_XEN_SCSI_BACKEND=m
+# frontend drivers
+CONFIG_XEN_FBDEV_FRONTEND=m
+CONFIG_HVC_XEN_FRONTEND=y
+CONFIG_INPUT_XEN_KBDDEV_FRONTEND=m
+CONFIG_XEN_SCSI_FRONTEND=m
+# others
+CONFIG_XEN_BALLOON=y
+CONFIG_XEN_SCRUB_PAGES=y
+CONFIG_XEN_DEV_EVTCHN=m
+CONFIG_XEN_BLKDEV_FRONTEND=m
+CONFIG_XEN_NETDEV_FRONTEND=m
+CONFIG_XENFS=m
+CONFIG_XEN_COMPAT_XENFS=y
+CONFIG_XEN_SYS_HYPERVISOR=y
+CONFIG_XEN_XENBUS_FRONTEND=y
+CONFIG_XEN_GNTDEV=m
+CONFIG_XEN_GRANT_DEV_ALLOC=m
+CONFIG_SWIOTLB_XEN=y
+CONFIG_XEN_PRIVCMD=m
diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index d9b1fef0c67e..f52abae0ec5f 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -115,6 +115,10 @@ PHONY += kvmconfig
 kvmconfig: kvm_guest.config
         @:
 
+PHONY += xenconfig
+xenconfig: xen.config
+        @:
+
 PHONY += tinyconfig
 tinyconfig:
         $(Q)$(MAKE) -f $(srctree)/Makefile allnoconfig tiny.config
@@ -139,7 +143,8 @@ help:
         @echo  '  randconfig      - New config with random answer to all options'
         @echo  '  listnewconfig   - List new options'
         @echo  '  olddefconfig    - Same as silentoldconfig but sets new symbols to their default value'
-        @echo  '  kvmconfig       - Enable additional options for guest kernel support'
+        @echo  '  kvmconfig       - Enable additional options for kvm guest kernel support'
+        @echo  '  xenconfig       - Enable additional options for xen dom0 and guest kernel support'
         @echo  '  tinyconfig      - Configure the tiniest possible kernel'
 
 # lxdialog stuff