[PATCH] xenfb: make restartable [Was: pv-grub doesn't run on rhel5]

[Samuel Thibault <samuel.thibault@eu.citrix.com>]

Samuel Thibault, le Thu 14 Aug 2008 16:14:00 +0100, a écrit :
> > Another pvgrub issue:  Is booting guests with the framebuffer enabled
> > supposed to work?
> 
> Yes, but you have to not enable the framebuffer in the grub
> configuration, because the framebuffer is currently not able to restart.

Oh actually it was a lot easier than I thought, see patch below (which
is actually partly bug fixes).



xenfb: make restartable

- Fix the pixel unmapping, which should happen during the Closing state.
- Fix qemu segfault when a guest shuts its fb down.
- Once connected, if frontend state goes from Closed to Initialized,
restart the connection loop.

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

diff -r 38783464a671 extras/mini-os/fbfront.c
--- a/extras/mini-os/fbfront.c	Thu Aug 14 16:16:44 2008 +0100
+++ b/extras/mini-os/fbfront.c	Thu Aug 14 18:59:27 2008 +0100
@@ -226,8 +226,7 @@ void shutdown_kbdfront(struct kbdfront_d
     xenbus_wait_for_value(path, "6", &dev->events);
 
     err = xenbus_printf(XBT_NIL, nodename, "state", "%u", 1);
-    // does not work yet.
-    //xenbus_wait_for_value(path, "2", &dev->events);
+    xenbus_wait_for_value(path, "2", &dev->events);
 
     xenbus_unwatch_path(XBT_NIL, path);
 
@@ -566,8 +565,7 @@ void shutdown_fbfront(struct fbfront_dev
     xenbus_wait_for_value(path, "6", &dev->events);
 
     err = xenbus_printf(XBT_NIL, nodename, "state", "%u", 1);
-    // does not work yet
-    //xenbus_wait_for_value(path, "2", &dev->events);
+    xenbus_wait_for_value(path, "2", &dev->events);
 
     xenbus_unwatch_path(XBT_NIL, path);
 
diff -r 38783464a671 stubdom/README
--- a/stubdom/README	Thu Aug 14 16:16:44 2008 +0100
+++ b/stubdom/README	Thu Aug 14 18:59:27 2008 +0100
@@ -126,9 +126,4 @@ Limitations
 ===========
 
 - You can not boot a 64bit kernel with a 32bit-compiled PV-GRUB and vice-versa.
-To cross-compile a 32bit PV-GRUB,
-
-export XEN_TARGET_ARCH=x86_32
-
-- bootsplash is supported, but the ioemu backend does not yet support restart
-for use by the booted kernel.
+You need to choose between pv-grub-x86_64.gz and pv-grub-x86_32.gz
diff -r 38783464a671 tools/ioemu/hw/xenfb.c
--- a/tools/ioemu/hw/xenfb.c	Thu Aug 14 16:16:44 2008 +0100
+++ b/tools/ioemu/hw/xenfb.c	Thu Aug 14 18:59:27 2008 +0100
@@ -445,6 +445,13 @@ static void xenfb_unbind(struct xenfb_de
 		xc_evtchn_unbind(dev->xenfb->evt_xch, dev->port);
 		dev->port = -1;
 	}
+
+	if (!strcmp(dev->devicetype, "vfb")) {
+	    if (dev->xenfb->pixels) {
+		    munmap(dev->xenfb->pixels, dev->xenfb->fb_len);
+		    dev->xenfb->pixels = NULL;
+	    }
+	}
 }
 
 
@@ -452,10 +459,6 @@ static void xenfb_detach_dom(struct xenf
 {
 	xenfb_unbind(&xenfb->fb);
 	xenfb_unbind(&xenfb->kbd);
-	if (xenfb->pixels) {
-		munmap(xenfb->pixels, xenfb->fb_len);
-		xenfb->pixels = NULL;
-	}
 }
 
 /* Remove the backend area in xenbus since the framebuffer really is
@@ -653,6 +656,16 @@ static int xenfb_on_state_change(struct 
 		   not much point in us continuing. */
 		return -1;
 	case XenbusStateInitialising:
+		if (dev->state != XenbusStateClosed)
+		    /* Do not let a domain make us skip the closing state */
+		    return 0;
+		xenfb_switch_state(dev, XenbusStateInitWait);
+		xs_unwatch(dev->xenfb->xsh, dev->otherend, "");
+		if (!strcmp(dev->devicetype, "vkbd")) {
+		    fprintf(stderr, "FB: Waiting for KBD backend creation\n");
+		    xenfb_wait_for_frontend(&dev->xenfb->kbd, xenfb_frontend_initialized_kbd);
+		}
+		break;
 	case XenbusStateInitWait:
 	case XenbusStateInitialised:
 	case XenbusStateConnected:
@@ -1274,6 +1287,9 @@ static void xenfb_update(void *opaque)
     struct xenfb *xenfb = opaque;
     int period;
 
+    if (!xenfb->fb.page)
+        return;
+
     if (xenfb_queue_full(xenfb))
         return;