s390: use virtio_console for KVM on s390

This patch enables virtio_console as the default console on kvm for s390. We currently use the same notify hack as lguest for early console output. I will try to address this for lguest and s390 later. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

s390: use virtio_console for KVM on s390
This patch enables virtio_console as the default console on kvm for s390. We currently use the same notify hack as lguest for early console output. I will try to address this for lguest and s390 later. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Christian Borntraeger · Rusty Russell
1 parent 7721c494a2
Showing 4 changed files with 34 additions and 1 deletions Side-by-side Diff
arch/s390/Kconfig
arch/s390/kernel/setup.c
drivers/s390/kvm/kvm_virtio.c
include/asm-s390/kvm_virtio.h
@@ -565,6 +565,7 @@
 	depends on 64BIT && EXPERIMENTAL
 	select VIRTIO
 	select VIRTIO_RING
+	select VIRTIO_CONSOLE
 	help
 	  Select this option if you want to run the kernel under s390 linux
 endmenu
@@ -54,6 +54,7 @@
 #include <asm/sections.h>
 #include <asm/ebcdic.h>
 #include <asm/compat.h>
+#include <asm/kvm_virtio.h>
  
 long psw_kernel_bits	= (PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_PRIMARY |
 			   PSW_MASK_MCHECK | PSW_DEFAULT_KEY);
@@ -766,7 +767,8 @@
 		printk("We are running under VM (64 bit mode)\n");
 	else if (MACHINE_IS_KVM) {
 		printk("We are running under KVM (64 bit mode)\n");
-		add_preferred_console("ttyS", 1, NULL);
+		add_preferred_console("hvc", 0, NULL);
+		s390_virtio_console_init();
 	} else
 		printk("We are running native (64 bit mode)\n");
 #endif /* CONFIG_64BIT */
@@ -15,6 +15,7 @@
 #include <linux/err.h>
 #include <linux/virtio.h>
 #include <linux/virtio_config.h>
+#include <linux/virtio_console.h>
 #include <linux/interrupt.h>
 #include <linux/virtio_ring.h>
 #include <linux/pfn.h>
@@ -331,6 +332,25 @@
  
 	scan_devices();
 	return 0;
+}
+
+/* code for early console output with virtio_console */
+static __init int early_put_chars(u32 vtermno, const char *buf, int count)
+{
+	char scratch[17];
+	unsigned int len = count;
+
+	if (len > sizeof(scratch) - 1)
+		len = sizeof(scratch) - 1;
+	scratch[len] = '\0';
+	memcpy(scratch, buf, len);
+	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, __pa(scratch));
+	return len;
+}
+
+void s390_virtio_console_init(void)
+{
+	virtio_cons_early_init(early_put_chars);
 }
  
 /*
@@ -50,5 +50,15 @@
 #define KVM_S390_VIRTIO_RESET		1
 #define KVM_S390_VIRTIO_SET_STATUS	2
  
+#ifdef __KERNEL__
+/* early virtio console setup */
+#ifdef CONFIG_VIRTIO_CONSOLE
+extern void s390_virtio_console_init(void);
+#else
+static inline void s390_virtio_console_init(void)
+{
+}
+#endif /* CONFIG_VIRTIO_CONSOLE */
+#endif /* __KERNEL__ */
 #endif
...	...	@@ -565,6 +565,7 @@
565	565	depends on 64BIT && EXPERIMENTAL
566	566	select VIRTIO
567	567	select VIRTIO_RING
	568	+ select VIRTIO_CONSOLE
568	569	help
569	570	Select this option if you want to run the kernel under s390 linux
570	571	endmenu
...	...	@@ -54,6 +54,7 @@
54	54	#include <asm/sections.h>
55	55	#include <asm/ebcdic.h>
56	56	#include <asm/compat.h>
	57	+#include <asm/kvm_virtio.h>
57	58
58	59	long psw_kernel_bits = (PSW_BASE_BITS \| PSW_MASK_DAT \| PSW_ASC_PRIMARY \|
59	60	PSW_MASK_MCHECK \| PSW_DEFAULT_KEY);
...	...	@@ -766,7 +767,8 @@
766	767	printk("We are running under VM (64 bit mode)\n");
767	768	else if (MACHINE_IS_KVM) {
768	769	printk("We are running under KVM (64 bit mode)\n");
769		- add_preferred_console("ttyS", 1, NULL);
	770	+ add_preferred_console("hvc", 0, NULL);
	771	+ s390_virtio_console_init();
770	772	} else
771	773	printk("We are running native (64 bit mode)\n");
772	774	#endif /* CONFIG_64BIT */
...	...	@@ -15,6 +15,7 @@
15	15	#include <linux/err.h>
16	16	#include <linux/virtio.h>
17	17	#include <linux/virtio_config.h>
	18	+#include <linux/virtio_console.h>
18	19	#include <linux/interrupt.h>
19	20	#include <linux/virtio_ring.h>
20	21	#include <linux/pfn.h>
...	...	@@ -331,6 +332,25 @@
331	332
332	333	scan_devices();
333	334	return 0;
	335	+}
	336	+
	337	+/* code for early console output with virtio_console */
	338	+static __init int early_put_chars(u32 vtermno, const char *buf, int count)
	339	+{
	340	+ char scratch[17];
	341	+ unsigned int len = count;
	342	+
	343	+ if (len > sizeof(scratch) - 1)
	344	+ len = sizeof(scratch) - 1;
	345	+ scratch[len] = '\0';
	346	+ memcpy(scratch, buf, len);
	347	+ kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, __pa(scratch));
	348	+ return len;
	349	+}
	350	+
	351	+void s390_virtio_console_init(void)
	352	+{
	353	+ virtio_cons_early_init(early_put_chars);
334	354	}
335	355
336	356	/*
...	...	@@ -50,5 +50,15 @@
50	50	#define KVM_S390_VIRTIO_RESET 1
51	51	#define KVM_S390_VIRTIO_SET_STATUS 2
52	52
	53	+#ifdef __KERNEL__
	54	+/* early virtio console setup */
	55	+#ifdef CONFIG_VIRTIO_CONSOLE
	56	+extern void s390_virtio_console_init(void);
	57	+#else
	58	+static inline void s390_virtio_console_init(void)
	59	+{
	60	+}
	61	+#endif /* CONFIG_VIRTIO_CONSOLE */
	62	+#endif /* __KERNEL__ */
53	63	#endif