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-rw-r--r--drivers/tty/hvc/hvc_xen.c5
-rw-r--r--drivers/xen/xenbus/xenbus_xs.c21
2 files changed, 25 insertions, 1 deletions
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 2944ff88fdc..f4abfe238f9 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -478,7 +478,6 @@ static void xencons_backend_changed(struct xenbus_device *dev,
case XenbusStateInitialising:
case XenbusStateInitialised:
case XenbusStateUnknown:
- case XenbusStateClosed:
break;
case XenbusStateInitWait:
@@ -488,6 +487,10 @@ static void xencons_backend_changed(struct xenbus_device *dev,
xenbus_switch_state(dev, XenbusStateConnected);
break;
+ case XenbusStateClosed:
+ if (dev->state == XenbusStateClosed)
+ break;
+ /* Missed the backend's CLOSING state -- fallthrough */
case XenbusStateClosing:
xenbus_frontend_closed(dev);
break;
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 131dec04794..48220e129f8 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -48,6 +48,7 @@
#include <xen/xenbus.h>
#include <xen/xen.h>
#include "xenbus_comms.h"
+#include <asm/xen/hypervisor.h>
struct xs_stored_msg {
struct list_head list;
@@ -618,7 +619,24 @@ static struct xenbus_watch *find_watch(const char *token)
return NULL;
}
+/*
+ * Certain older XenBus toolstack cannot handle reading values that are
+ * not populated. Some Xen 3.4 installation are incapable of doing this
+ * so if we are running on anything older than 4 do not attempt to read
+ * control/platform-feature-xs_reset_watches.
+ */
+static bool xen_strict_xenbus_quirk()
+{
+ uint32_t eax, ebx, ecx, edx, base;
+
+ base = xen_cpuid_base();
+ cpuid(base + 1, &eax, &ebx, &ecx, &edx);
+ if ((eax >> 16) < 4)
+ return true;
+ return false;
+
+}
static void xs_reset_watches(void)
{
int err, supported = 0;
@@ -626,6 +644,9 @@ static void xs_reset_watches(void)
if (!xen_hvm_domain() || xen_initial_domain())
return;
+ if (xen_strict_xenbus_quirk())
+ return;
+
err = xenbus_scanf(XBT_NIL, "control",
"platform-feature-xs_reset_watches", "%d", &supported);
if (err != 1 || !supported)