7 files changed, 30 insertions, 42 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 49ee13372e5b..e8e1d86bd505 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16317,6 +16317,7 @@ F:	arch/arm64/include/asm/xen/
 XEN HYPERVISOR INTERFACE
 M:      Boris Ostrovsky <boris.ostrovsky@oracle.com>
 M:      Juergen Gross <jgross@suse.com>
+R:      Stefano Stabellini <sstabellini@kernel.org>
 L:      xen-devel@lists.xenproject.org (moderated for non-subscribers)
 T:      git git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git
 S:      Supported
diff --git a/arch/x86/xen/platform-pci-unplug.c b/arch/x86/xen/platform-pci-unplug.c
index 66ab96a4e2b3..96d7f7d39cb9 100644
--- a/arch/x86/xen/platform-pci-unplug.c
+++ b/arch/x86/xen/platform-pci-unplug.c
@@ -134,6 +134,10 @@ void xen_unplug_emulated_devices(void)
 {
         int r;
 
+        /* PVH guests don't have emulated devices. */
+        if (xen_pvh_domain())
+                return;
+
         /* user explicitly requested no unplug */
         if (xen_emul_unplug & XEN_UNPLUG_NEVER)
                 return;
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 23f6793af88a..441c88262169 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -39,34 +39,25 @@ static void xen_qlock_kick(int cpu)
  */
 static void xen_qlock_wait(u8 *byte, u8 val)
 {
+        unsigned long flags;
         int irq = __this_cpu_read(lock_kicker_irq);
 
         /* If kicker interrupts not initialized yet, just spin */
-        if (irq == -1)
+        if (irq == -1 || in_nmi())
                 return;
 
-        /* clear pending */
-        xen_clear_irq_pending(irq);
-        barrier();
-
-        /*
-         * We check the byte value after clearing pending IRQ to make sure
-         * that we won't miss a wakeup event because of the clearing.
-         *
-         * The sync_clear_bit() call in xen_clear_irq_pending() is atomic.
-         * So it is effectively a memory barrier for x86.
-         */
-        if (READ_ONCE(*byte) != val)
-                return;
+        /* Guard against reentry. */
+        local_irq_save(flags);
 
-        /*
-         * If an interrupt happens here, it will leave the wakeup irq
-         * pending, which will cause xen_poll_irq() to return
-         * immediately.
-         */
+        /* If irq pending already clear it. */
+        if (xen_test_irq_pending(irq)) {
+                xen_clear_irq_pending(irq);
+        } else if (READ_ONCE(*byte) == val) {
+                /* Block until irq becomes pending (or a spurious wakeup) */
+                xen_poll_irq(irq);
+        }
 
-        /* Block until irq becomes pending (or perhaps a spurious wakeup) */
-        xen_poll_irq(irq);
+        local_irq_restore(flags);
 }
 
 static irqreturn_t dummy_handler(int irq, void *dev_id)
diff --git a/arch/x86/xen/xen-pvh.S b/arch/x86/xen/xen-pvh.S
index b0e471506cd8..1f8825bbaffb 100644
--- a/arch/x86/xen/xen-pvh.S
+++ b/arch/x86/xen/xen-pvh.S
@@ -170,7 +170,7 @@ canary:
         .fill 48, 1, 0
 
 early_stack:
-        .fill 256, 1, 0
+        .fill BOOT_STACK_SIZE, 1, 0
 early_stack_end:
 
         ELFNOTE(Xen, XEN_ELFNOTE_PHYS32_ENTRY,
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 90d387b50ab7..815b9e9bb975 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -12,7 +12,6 @@ config XEN_BALLOON
 config XEN_SELFBALLOONING
         bool "Dynamically self-balloon kernel memory to target"
         depends on XEN && XEN_BALLOON && CLEANCACHE && SWAP && XEN_TMEM
-        default n
         help
           Self-ballooning dynamically balloons available kernel memory driven
           by the current usage of anonymous memory ("committed AS") and
@@ -27,7 +26,6 @@ config XEN_SELFBALLOONING
 
 config XEN_BALLOON_MEMORY_HOTPLUG
         bool "Memory hotplug support for Xen balloon driver"
-        default n
         depends on XEN_BALLOON && MEMORY_HOTPLUG
         help
           Memory hotplug support for Xen balloon driver allows expanding memory
@@ -86,7 +84,7 @@ config XEN_SCRUB_PAGES_DEFAULT
         help
           Scrub pages before returning them to the system for reuse by
           other domains.  This makes sure that any confidential data
-          is not accidentally visible to other domains.  Is it more
+          is not accidentally visible to other domains.  It is more
           secure, but slightly less efficient. This can be controlled with
           xen_scrub_pages=0 parameter and
           /sys/devices/system/xen_memory/xen_memory0/scrub_pages.
@@ -105,8 +103,7 @@ config XEN_DEV_EVTCHN
 
 config XEN_BACKEND
         bool "Backend driver support"
-        depends on XEN_DOM0
-        default y
+        default XEN_DOM0
         help
           Support for backend device drivers that provide I/O services
           to other virtual machines.
@@ -227,7 +224,6 @@ config XEN_PCIDEV_BACKEND
 config XEN_PVCALLS_FRONTEND
         tristate "XEN PV Calls frontend driver"
         depends on INET && XEN
-        default n
         select XEN_XENBUS_FRONTEND
         help
           Experimental frontend for the Xen PV Calls protocol
@@ -238,7 +234,6 @@ config XEN_PVCALLS_FRONTEND
 config XEN_PVCALLS_BACKEND
         bool "XEN PV Calls backend driver"
         depends on INET && XEN && XEN_BACKEND
-        default n
         help
           Experimental backend for the Xen PV Calls protocol
           (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
@@ -264,7 +259,6 @@ config XEN_PRIVCMD
 config XEN_STUB
         bool "Xen stub drivers"
         depends on XEN && X86_64 && BROKEN
-        default n
         help
           Allow kernel to install stub drivers, to reserve space for Xen drivers,
           i.e. memory hotplug and cpu hotplug, and to block native drivers loaded,
@@ -275,7 +269,6 @@ config XEN_STUB
 config XEN_ACPI_HOTPLUG_MEMORY
         tristate "Xen ACPI memory hotplug"
         depends on XEN_DOM0 && XEN_STUB && ACPI
-        default n
         help
           This is Xen ACPI memory hotplug.
 
@@ -287,7 +280,6 @@ config XEN_ACPI_HOTPLUG_CPU
         tristate "Xen ACPI cpu hotplug"
         depends on XEN_DOM0 && XEN_STUB && ACPI
         select ACPI_CONTAINER
-        default n
         help
           Xen ACPI cpu enumerating and hotplugging
 
@@ -316,7 +308,6 @@ config XEN_ACPI_PROCESSOR
 config XEN_MCE_LOG
         bool "Xen platform mcelog"
         depends on XEN_DOM0 && X86_64 && X86_MCE
-        default n
         help
           Allow kernel fetching MCE error from Xen platform and
           converting it into Linux mcelog format for mcelog tools
diff --git a/drivers/xen/xen-balloon.c b/drivers/xen/xen-balloon.c
index 63c1494a8d73..2acbfe104e46 100644
--- a/drivers/xen/xen-balloon.c
+++ b/drivers/xen/xen-balloon.c
@@ -76,12 +76,15 @@ static void watch_target(struct xenbus_watch *watch,
 
         if (!watch_fired) {
                 watch_fired = true;
-                err = xenbus_scanf(XBT_NIL, "memory", "static-max", "%llu",
-                                   &static_max);
-                if (err != 1)
-                        static_max = new_target;
-                else
+
+                if ((xenbus_scanf(XBT_NIL, "memory", "static-max",
+                                  "%llu", &static_max) == 1) ||
+                    (xenbus_scanf(XBT_NIL, "memory", "memory_static_max",
+                                  "%llu", &static_max) == 1))
                         static_max >>= PAGE_SHIFT - 10;
+                else
+                        static_max = new_target;
+
                 target_diff = (xen_pv_domain() || xen_initial_domain()) ? 0
                                 : static_max - balloon_stats.target_pages;
         }
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index a1c17000129b..e17ca8156171 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -278,10 +278,8 @@ static void xenbus_va_dev_error(struct xenbus_device *dev, int err,
         dev_err(&dev->dev, "%s\n", printf_buffer);
 
         path_buffer = kasprintf(GFP_KERNEL, "error/%s", dev->nodename);
-        if (!path_buffer ||
-            xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer))
-                dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
-                        dev->nodename, printf_buffer);
+        if (path_buffer)
+                xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer);
 
         kfree(printf_buffer);
         kfree(path_buffer);