---

yaml --- r: 310926 b: refs/heads/master c: 5842f57 h: refs/heads/master v: v3
git-mirror · May 24, 2012 · 4fd7356 · 4fd7356
1 parent c4204fa
commit 4fd7356
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Showing 2 changed files with 9 additions and 4 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a32c88b9386ce3df87f28dd46bdc3776cd6edf75
+refs/heads/master: 5842f5768599094758931b74190cdf93641a8e35
diff --git a/trunk/drivers/tty/hvc/hvc_xen.c b/trunk/drivers/tty/hvc/hvc_xen.c
@@ -214,14 +214,19 @@ static int xen_hvm_console_init(void)
 	/* already configured */
 	if (info->intf != NULL)
 		return 0;
-
+	/*
+	 * If the toolstack (or the hypervisor) hasn't set these values, the
+	 * default value is 0. Even though mfn = 0 and evtchn = 0 are
+	 * theoretically correct values, in practice they never are and they
+	 * mean that a legacy toolstack hasn't initialized the pv console correctly.
+	 */
 	r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
-	if (r < 0)
+	if (r < 0 || v == 0)
 		goto err;
 	info->evtchn = v;
 	v = 0;
 	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
-	if (r < 0)
+	if (r < 0 || v == 0)
 		goto err;
 	mfn = v;
 	info->intf = ioremap(mfn << PAGE_SHIFT, PAGE_SIZE);