Merge branch 'for-upstream/pvhvm' of git://xenbits.xensource.com/people/ianc/linux-2.6

* 'for-upstream/pvhvm' of git://xenbits.xensource.com/people/ianc/linux-2.6:
  xen: pvhvm: make it clearer that XEN_UNPLUG_* define bits in a bitfield
  xen: pvhvm: rename xen_emul_unplug=ignore to =unnnecessary
  xen: pvhvm: allow user to request no emulated device unplug

Documentation/kernel-parameters.txt

@@ -2629,8 +2629,10 @@ and is between 256 and 4096 characters. It is defined in the file
 			aux-ide-disks -- unplug non-primary-master IDE devices
 			nics -- unplug network devices
 			all -- unplug all emulated devices (NICs and IDE disks)
-			ignore -- continue loading the Xen platform PCI driver even
+			unnecessary -- unplugging emulated devices is
-				if the version check failed
+				unnecessary even if the host did not respond to
+				the unplug protocol
+			never -- do not unplug even if version check succeeds
 
 	xirc2ps_cs=	[NET,PCMCIA]
 			Format:

arch/x86/xen/platform-pci-unplug.c

@@ -72,13 +72,17 @@ void __init xen_unplug_emulated_devices(void)
 {
 	int r;
 
+	/* user explicitly requested no unplug */
+	if (xen_emul_unplug & XEN_UNPLUG_NEVER)
+		return;
 	/* check the version of the xen platform PCI device */
 	r = check_platform_magic();
 	/* If the version matches enable the Xen platform PCI driver.
-	 * Also enable the Xen platform PCI driver if the version is really old
+	 * Also enable the Xen platform PCI driver if the host does
-	 * and the user told us to ignore it. */
+	 * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
+	 * but the user told us that unplugging is unnecessary. */
 	if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
-			(xen_emul_unplug & XEN_UNPLUG_IGNORE)))
+			(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
 		return;
 	/* Set the default value of xen_emul_unplug depending on whether or
 	 * not the Xen PV frontends and the Xen platform PCI driver have
@@ -99,7 +103,7 @@ void __init xen_unplug_emulated_devices(void)
 		}
 	}
 	/* Now unplug the emulated devices */
-	if (!(xen_emul_unplug & XEN_UNPLUG_IGNORE))
+	if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
 		outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
 	xen_platform_pci_unplug = xen_emul_unplug;
 }
@@ -125,8 +129,10 @@ static int __init parse_xen_emul_unplug(char *arg)
 			xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
 		else if (!strncmp(p, "nics", l))
 			xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
-		else if (!strncmp(p, "ignore", l))
+		else if (!strncmp(p, "unnecessary", l))
-			xen_emul_unplug |= XEN_UNPLUG_IGNORE;
+			xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
+		else if (!strncmp(p, "never", l))
+			xen_emul_unplug |= XEN_UNPLUG_NEVER;
 		else
 			printk(KERN_WARNING "unrecognised option '%s' "
 				 "in parameter 'xen_emul_unplug'\n", p);

drivers/block/xen-blkfront.c

@@ -834,7 +834,7 @@ static int blkfront_probe(struct xenbus_device *dev,
 		char *type;
 		int len;
 		/* no unplug has been done: do not hook devices != xen vbds */
-		if (xen_platform_pci_unplug & XEN_UNPLUG_IGNORE) {
+		if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) {
 			int major;
 
 			if (!VDEV_IS_EXTENDED(vdevice))

include/xen/platform_pci.h

@@ -16,11 +16,15 @@
 #define XEN_IOPORT_PROTOVER	(XEN_IOPORT_BASE + 2) /* 1 byte access (R) */
 #define XEN_IOPORT_PRODNUM	(XEN_IOPORT_BASE + 2) /* 2 byte access (W) */
 
-#define XEN_UNPLUG_ALL_IDE_DISKS 1
+#define XEN_UNPLUG_ALL_IDE_DISKS	(1<<0)
-#define XEN_UNPLUG_ALL_NICS 2
+#define XEN_UNPLUG_ALL_NICS		(1<<1)
-#define XEN_UNPLUG_AUX_IDE_DISKS 4
+#define XEN_UNPLUG_AUX_IDE_DISKS	(1<<2)
-#define XEN_UNPLUG_ALL 7
+#define XEN_UNPLUG_ALL			(XEN_UNPLUG_ALL_IDE_DISKS|\
-#define XEN_UNPLUG_IGNORE 8
+					 XEN_UNPLUG_ALL_NICS|\
+					 XEN_UNPLUG_AUX_IDE_DISKS)
+
+#define XEN_UNPLUG_UNNECESSARY 		(1<<16)
+#define XEN_UNPLUG_NEVER	 		(1<<17)
 
 static inline int xen_must_unplug_nics(void) {
 #if (defined(CONFIG_XEN_NETDEV_FRONTEND) || \