Merge tag 'stable/for-linus-3.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull Xen fixes from David Vrabel:
 "Xen regression and bug fixes for 3.15-rc1:

   - fix completely broken 32-bit PV guests caused by x86 refactoring
     32-bit thread_info.
   - only enable ticketlock slow path on Xen (not bare metal)
   - fix two bugs with PV guests not shutting down when requested
   - fix a minor memory leak in xen-pciback error path"

* tag 'stable/for-linus-3.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/manage: Poweroff forcefully if user-space is not yet up.
  xen/xenbus: Avoid synchronous wait on XenBus stalling shutdown/restart.
  xen/spinlock: Don't enable them unconditionally.
  xen-pciback: silence an unwanted debug printk
  xen: fix memory leak in __xen_pcibk_add_pci_dev()
  x86/xen: Fix 32-bit PV guests's usage of kernel_stack

7 files changed, 98 insertions, 16 deletions

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index a18eadd8bb40..7005974c3ff3 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -441,10 +441,11 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
         irq_ctx_init(cpu);
 #else
         clear_tsk_thread_flag(idle, TIF_FORK);
+#endif
         per_cpu(kernel_stack, cpu) =
                 (unsigned long)task_stack_page(idle) -
                 KERNEL_STACK_OFFSET + THREAD_SIZE;
-#endif
+
         xen_setup_runstate_info(cpu);
         xen_setup_timer(cpu);
         xen_init_lock_cpu(cpu);
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 4d3acc34a998..0ba5f3b967f0 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -274,7 +274,7 @@ void __init xen_init_spinlocks(void)
                 printk(KERN_DEBUG "xen: PV spinlocks disabled\n");
                 return;
         }
-
+        printk(KERN_DEBUG "xen: PV spinlocks enabled\n");
         pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning);
         pv_lock_ops.unlock_kick = xen_unlock_kick;
 }
@@ -290,6 +290,9 @@ static __init int xen_init_spinlocks_jump(void)
         if (!xen_pvspin)
                 return 0;
 
+        if (!xen_domain())
+                return 0;
+
         static_key_slow_inc(&paravirt_ticketlocks_enabled);
         return 0;
 }
diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S
index 33ca6e42a4ca..fd92a64d748e 100644
--- a/arch/x86/xen/xen-asm_32.S
+++ b/arch/x86/xen/xen-asm_32.S
@@ -75,6 +75,17 @@ ENDPROC(xen_sysexit)
  * stack state in whatever form its in, we keep things simple by only
  * using a single register which is pushed/popped on the stack.
  */
+
+.macro POP_FS
+1:
+        popw %fs
+.pushsection .fixup, "ax"
+2:      movw $0, (%esp)
+        jmp 1b
+.popsection
+        _ASM_EXTABLE(1b,2b)
+.endm
+
 ENTRY(xen_iret)
         /* test eflags for special cases */
         testl $(X86_EFLAGS_VM | XEN_EFLAGS_NMI), 8(%esp)
@@ -83,15 +94,13 @@ ENTRY(xen_iret)
         push %eax
         ESP_OFFSET=4    # bytes pushed onto stack
 
-        /*
-         * Store vcpu_info pointer for easy access.  Do it this way to
-         * avoid having to reload %fs
-         */
+        /* Store vcpu_info pointer for easy access */
 #ifdef CONFIG_SMP
-        GET_THREAD_INFO(%eax)
-        movl %ss:TI_cpu(%eax), %eax
-        movl %ss:__per_cpu_offset(,%eax,4), %eax
-        mov %ss:xen_vcpu(%eax), %eax
+        pushw %fs
+        movl $(__KERNEL_PERCPU), %eax
+        movl %eax, %fs
+        movl %fs:xen_vcpu, %eax
+        POP_FS
 #else
         movl %ss:xen_vcpu, %eax
 #endif
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index fc6c94c0b436..32f9236c959f 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -198,10 +198,32 @@ struct shutdown_handler {
         void (*cb)(void);
 };
 
+static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
+{
+        switch (code) {
+        case SYS_DOWN:
+        case SYS_HALT:
+        case SYS_POWER_OFF:
+                shutting_down = SHUTDOWN_POWEROFF;
+        default:
+                break;
+        }
+        return NOTIFY_DONE;
+}
 static void do_poweroff(void)
 {
-        shutting_down = SHUTDOWN_POWEROFF;
-        orderly_poweroff(false);
+        switch (system_state) {
+        case SYSTEM_BOOTING:
+                orderly_poweroff(true);
+                break;
+        case SYSTEM_RUNNING:
+                orderly_poweroff(false);
+                break;
+        default:
+                /* Don't do it when we are halting/rebooting. */
+                pr_info("Ignoring Xen toolstack shutdown.\n");
+                break;
+        }
 }
 
 static void do_reboot(void)
@@ -307,6 +329,10 @@ static struct xenbus_watch shutdown_watch = {
         .callback = shutdown_handler
 };
 
+static struct notifier_block xen_reboot_nb = {
+        .notifier_call = poweroff_nb,
+};
+
 static int setup_shutdown_watcher(void)
 {
         int err;
@@ -317,6 +343,7 @@ static int setup_shutdown_watcher(void)
                 return err;
         }
 
+
 #ifdef CONFIG_MAGIC_SYSRQ
         err = register_xenbus_watch(&sysrq_watch);
         if (err) {
@@ -345,6 +372,7 @@ int xen_setup_shutdown_event(void)
         if (!xen_domain())
                 return -ENODEV;
         register_xenstore_notifier(&xenstore_notifier);
+        register_reboot_notifier(&xen_reboot_nb);
 
         return 0;
 }
diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c
index 929dd46bb40c..607e41460c0d 100644
--- a/drivers/xen/xen-pciback/pciback_ops.c
+++ b/drivers/xen/xen-pciback/pciback_ops.c
@@ -217,7 +217,7 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
         if (result == 0) {
                 for (i = 0; i < op->value; i++) {
                         op->msix_entries[i].entry = entries[i].entry;
-                        if (entries[i].vector)
+                        if (entries[i].vector) {
                                 op->msix_entries[i].vector =
                                         xen_pirq_from_irq(entries[i].vector);
                                 if (unlikely(verbose_request))
@@ -225,6 +225,7 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
                                                 "MSI-X[%d]: %d\n",
                                                 pci_name(dev), i,
                                                 op->msix_entries[i].vector);
+                        }
                 }
         } else
                 pr_warn_ratelimited("%s: error enabling MSI-X for guest %u: err %d!\n",
diff --git a/drivers/xen/xen-pciback/vpci.c b/drivers/xen/xen-pciback/vpci.c
index 3165ce361b00..51afff96c515 100644
--- a/drivers/xen/xen-pciback/vpci.c
+++ b/drivers/xen/xen-pciback/vpci.c
@@ -137,6 +137,8 @@ unlock:
         /* Publish this device. */
         if (!err)
                 err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
+        else
+                kfree(dev_entry);
 
 out:
         return err;
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index b6d5fff43d16..ba804f3d8278 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -50,6 +50,7 @@
 #include <xen/xenbus.h>
 #include <xen/xen.h>
 #include "xenbus_comms.h"
+#include "xenbus_probe.h"
 
 struct xs_stored_msg {
         struct list_head list;
@@ -139,6 +140,29 @@ static int get_error(const char *errorstring)
         return xsd_errors[i].errnum;
 }
 
+static bool xenbus_ok(void)
+{
+        switch (xen_store_domain_type) {
+        case XS_LOCAL:
+                switch (system_state) {
+                case SYSTEM_POWER_OFF:
+                case SYSTEM_RESTART:
+                case SYSTEM_HALT:
+                        return false;
+                default:
+                        break;
+                }
+                return true;
+        case XS_PV:
+        case XS_HVM:
+                /* FIXME: Could check that the remote domain is alive,
+                 * but it is normally initial domain. */
+                return true;
+        default:
+                break;
+        }
+        return false;
+}
 static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len)
 {
         struct xs_stored_msg *msg;
@@ -148,9 +172,20 @@ static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len)
 
         while (list_empty(&xs_state.reply_list)) {
                 spin_unlock(&xs_state.reply_lock);
-                /* XXX FIXME: Avoid synchronous wait for response here. */
-                wait_event(xs_state.reply_waitq,
-                           !list_empty(&xs_state.reply_list));
+                if (xenbus_ok())
+                        /* XXX FIXME: Avoid synchronous wait for response here. */
+                        wait_event_timeout(xs_state.reply_waitq,
+                                           !list_empty(&xs_state.reply_list),
+                                           msecs_to_jiffies(500));
+                else {
+                        /*
+                         * If we are in the process of being shut-down there is
+                         * no point of trying to contact XenBus - it is either
+                         * killed (xenstored application) or the other domain
+                         * has been killed or is unreachable.
+                         */
+                        return ERR_PTR(-EIO);
+                }
                 spin_lock(&xs_state.reply_lock);
         }
 
@@ -215,6 +250,9 @@ void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
 
         mutex_unlock(&xs_state.request_mutex);
 
+        if (IS_ERR(ret))
+                return ret;
+
         if ((msg->type == XS_TRANSACTION_END) ||
             ((req_msg.type == XS_TRANSACTION_START) &&
              (msg->type == XS_ERROR)))