Merge branch 'bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen

* 'bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: xen: mask extended topology info in cpuid xen/hvc: make sure console output is always emitted, with explicit polling

Merge branch 'bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen
* 'bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: xen: mask extended topology info in cpuid xen/hvc: make sure console output is always emitted, with explicit polling
Linus Torvalds
2 parents d4116f8204 82d6469916
Showing 2 changed files Side-by-side Diff
arch/x86/xen/enlighten.c
drivers/char/hvc_xen.c
@@ -178,6 +178,7 @@
 static void xen_cpuid(unsigned int *ax, unsigned int *bx,
 		      unsigned int *cx, unsigned int *dx)
 {
+	unsigned maskebx = ~0;
 	unsigned maskecx = ~0;
 	unsigned maskedx = ~0;
  
  
@@ -185,9 +186,16 @@
 	 * Mask out inconvenient features, to try and disable as many
 	 * unsupported kernel subsystems as possible.
 	 */
-	if (*ax == 1) {
+	switch (*ax) {
+	case 1:
 		maskecx = cpuid_leaf1_ecx_mask;
 		maskedx = cpuid_leaf1_edx_mask;
+		break;
+
+	case 0xb:
+		/* Suppress extended topology stuff */
+		maskebx = 0;
+		break;
 	}
  
 	asm(XEN_EMULATE_PREFIX "cpuid"
@@ -197,6 +205,7 @@
 		  "=d" (*dx)
 		: "0" (*ax), "2" (*cx));
  
+	*bx &= maskebx;
 	*cx &= maskecx;
 	*dx &= maskedx;
 }
@@ -55,7 +55,7 @@
 	notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
 }
  
-static int write_console(uint32_t vtermno, const char *data, int len)
+static int __write_console(const char *data, int len)
 {
 	struct xencons_interface *intf = xencons_interface();
 	XENCONS_RING_IDX cons, prod;
@@ -74,6 +74,29 @@
  
 	notify_daemon();
 	return sent;
+}
+
+static int write_console(uint32_t vtermno, const char *data, int len)
+{
+	int ret = len;
+
+	/*
+	 * Make sure the whole buffer is emitted, polling if
+	 * necessary.  We don't ever want to rely on the hvc daemon
+	 * because the most interesting console output is when the
+	 * kernel is crippled.
+	 */
+	while (len) {
+		int sent = __write_console(data, len);
+		
+		data += sent;
+		len -= sent;
+
+		if (unlikely(len))
+			HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
+	}
+
+	return ret;
 }
  
 static int read_console(uint32_t vtermno, char *buf, int len)
...	...	@@ -178,6 +178,7 @@
178	178	static void xen_cpuid(unsigned int ax, unsigned int bx,
179	179	unsigned int cx, unsigned int dx)
180	180	{
	181	+ unsigned maskebx = ~0;
181	182	unsigned maskecx = ~0;
182	183	unsigned maskedx = ~0;
183	184
184	185
...	...	@@ -185,9 +186,16 @@
185	186	* Mask out inconvenient features, to try and disable as many
186	187	* unsupported kernel subsystems as possible.
187	188	*/
188		- if (*ax == 1) {
	189	+ switch (*ax) {
	190	+ case 1:
189	191	maskecx = cpuid_leaf1_ecx_mask;
190	192	maskedx = cpuid_leaf1_edx_mask;
	193	+ break;
	194	+
	195	+ case 0xb:
	196	+ /* Suppress extended topology stuff */
	197	+ maskebx = 0;
	198	+ break;
191	199	}
192	200
193	201	asm(XEN_EMULATE_PREFIX "cpuid"
...	...	@@ -197,6 +205,7 @@
197	205	"=d" (*dx)
198	206	: "0" (ax), "2" (cx));
199	207
	208	+ *bx &= maskebx;
200	209	*cx &= maskecx;
201	210	*dx &= maskedx;
202	211	}
...	...	@@ -55,7 +55,7 @@
55	55	notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
56	56	}
57	57
58		-static int write_console(uint32_t vtermno, const char *data, int len)
	58	+static int __write_console(const char *data, int len)
59	59	{
60	60	struct xencons_interface *intf = xencons_interface();
61	61	XENCONS_RING_IDX cons, prod;
...	...	@@ -74,6 +74,29 @@
74	74
75	75	notify_daemon();
76	76	return sent;
	77	+}
	78	+
	79	+static int write_console(uint32_t vtermno, const char *data, int len)
	80	+{
	81	+ int ret = len;
	82	+
	83	+ /*
	84	+ * Make sure the whole buffer is emitted, polling if
	85	+ * necessary. We don't ever want to rely on the hvc daemon
	86	+ * because the most interesting console output is when the
	87	+ * kernel is crippled.
	88	+ */
	89	+ while (len) {
	90	+ int sent = __write_console(data, len);
	91	+
	92	+ data += sent;
	93	+ len -= sent;
	94	+
	95	+ if (unlikely(len))
	96	+ HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
	97	+ }
	98	+
	99	+ return ret;
77	100	}
78	101
79	102	static int read_console(uint32_t vtermno, char *buf, int len)