xen: make hvc_xen console work for dom0.

Use the console hypercalls for dom0 console.

[ Impact: Add Xen dom0 console ]
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 65 insertions, 33 deletions

diff --git a/drivers/char/hvc_xen.c b/drivers/char/hvc_xen.c
index 60446f82a3fc..1f7e13a43a88 100644
--- a/drivers/char/hvc_xen.c
+++ b/drivers/char/hvc_xen.c
@@ -78,7 +78,7 @@ static int __write_console(const char *data, int len)
         return sent;
 }
 
-static int write_console(uint32_t vtermno, const char *data, int len)
+static int domU_write_console(uint32_t vtermno, const char *data, int len)
 {
         int ret = len;
 
@@ -101,7 +101,7 @@ static int write_console(uint32_t vtermno, const char *data, int len)
         return ret;
 }
 
-static int read_console(uint32_t vtermno, char *buf, int len)
+static int domU_read_console(uint32_t vtermno, char *buf, int len)
 {
         struct xencons_interface *intf = xencons_interface();
         XENCONS_RING_IDX cons, prod;
@@ -122,28 +122,62 @@ static int read_console(uint32_t vtermno, char *buf, int len)
         return recv;
 }
 
-static const struct hv_ops hvc_ops = {
-        .get_chars = read_console,
-        .put_chars = write_console,
+static struct hv_ops domU_hvc_ops = {
+        .get_chars = domU_read_console,
+        .put_chars = domU_write_console,
         .notifier_add = notifier_add_irq,
         .notifier_del = notifier_del_irq,
         .notifier_hangup = notifier_hangup_irq,
 };
 
-static int __init xen_init(void)
+static int dom0_read_console(uint32_t vtermno, char *buf, int len)
+{
+        return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
+}
+
+/*
+ * Either for a dom0 to write to the system console, or a domU with a
+ * debug version of Xen
+ */
+static int dom0_write_console(uint32_t vtermno, const char *str, int len)
+{
+        int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
+        if (rc < 0)
+                return 0;
+
+        return len;
+}
+
+static struct hv_ops dom0_hvc_ops = {
+        .get_chars = dom0_read_console,
+        .put_chars = dom0_write_console,
+        .notifier_add = notifier_add_irq,
+        .notifier_del = notifier_del_irq,
+        .notifier_hangup = notifier_hangup_irq,
+};
+
+static int __init xen_hvc_init(void)
 {
         struct hvc_struct *hp;
+        struct hv_ops *ops;
 
-        if (!xen_pv_domain() ||
-            xen_initial_domain() ||
-            !xen_start_info->console.domU.evtchn)
+        if (!xen_pv_domain())
                 return -ENODEV;
 
-        xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
+        if (xen_initial_domain()) {
+                ops = &dom0_hvc_ops;
+                xencons_irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
+        } else {
+                if (!xen_start_info->console.domU.evtchn)
+                        return -ENODEV;
+
+                ops = &domU_hvc_ops;
+                xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
+        }
         if (xencons_irq < 0)
                 xencons_irq = 0; /* NO_IRQ */
 
-        hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256);
+        hp = hvc_alloc(HVC_COOKIE, xencons_irq, ops, 256);
         if (IS_ERR(hp))
                 return PTR_ERR(hp);
 
@@ -160,7 +194,7 @@ void xen_console_resume(void)
                 rebind_evtchn_irq(xen_start_info->console.domU.evtchn, xencons_irq);
 }
 
-static void __exit xen_fini(void)
+static void __exit xen_hvc_fini(void)
 {
         if (hvc)
                 hvc_remove(hvc);
@@ -168,29 +202,24 @@ static void __exit xen_fini(void)
 
 static int xen_cons_init(void)
 {
+        struct hv_ops *ops;
+
         if (!xen_pv_domain())
                 return 0;
 
-        hvc_instantiate(HVC_COOKIE, 0, &hvc_ops);
+        if (xen_initial_domain())
+                ops = &dom0_hvc_ops;
+        else
+                ops = &domU_hvc_ops;
+
+        hvc_instantiate(HVC_COOKIE, 0, ops);
         return 0;
 }
 
-module_init(xen_init);
-module_exit(xen_fini);
+module_init(xen_hvc_init);
+module_exit(xen_hvc_fini);
 console_initcall(xen_cons_init);
 
-static void raw_console_write(const char *str, int len)
-{
-        while(len > 0) {
-                int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
-                if (rc <= 0)
-                        break;
-
-                str += rc;
-                len -= rc;
-        }
-}
-
 #ifdef CONFIG_EARLY_PRINTK
 static void xenboot_write_console(struct console *console, const char *string,
                                   unsigned len)
@@ -198,19 +227,22 @@ static void xenboot_write_console(struct console *console, const char *string,
         unsigned int linelen, off = 0;
         const char *pos;
 
-        raw_console_write(string, len);
+        dom0_write_console(0, string, len);
+
+        if (xen_initial_domain())
+                return;
 
-        write_console(0, "(early) ", 8);
+        domU_write_console(0, "(early) ", 8);
         while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
                 linelen = pos-string+off;
                 if (off + linelen > len)
                         break;
-                write_console(0, string+off, linelen);
-                write_console(0, "\r\n", 2);
+                domU_write_console(0, string+off, linelen);
+                domU_write_console(0, "\r\n", 2);
                 off += linelen + 1;
         }
         if (off < len)
-                write_console(0, string+off, len-off);
+                domU_write_console(0, string+off, len-off);
 }
 
 struct console xenboot_console = {
@@ -222,7 +254,7 @@ struct console xenboot_console = {
 
 void xen_raw_console_write(const char *str)
 {
-        raw_console_write(str, strlen(str));
+        dom0_write_console(0, str, strlen(str));
 }
 
 void xen_raw_printk(const char *fmt, ...)