[v1,2/3] xen/console: introduce console_puts()

Commit Message

Denis Mukhin April 3, 2025, 12:06 a.m. UTC

From: Denis Mukhin <[e-mail]>

guest_console_write() duplicates the code from __putstr(), eliminate code
duplication.

Introduce console_puts() for writing a buffer to console devices.

Also, introduce internal console flags to control which console devices
should be used.

Signed-off-by: Denis Mukhin <[e-mail]>
---
 xen/drivers/char/console.c | 112 ++++++++++++++++++++++---------------
 1 file changed, 66 insertions(+), 46 deletions(-)

Patch

diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index aaa97088aa..2618c2e47d 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -41,6 +41,20 @@ 
 #include <asm/vpl011.h>
 #endif
 
+/* Internal console flags. */
+enum {
+    CONSOLE_SERIAL  = BIT(0, U),    /* Use serial device. */
+    CONSOLE_PV      = BIT(1, U),    /* Use PV console. */
+    CONSOLE_VIDEO   = BIT(2, U),    /* Use video device. */
+    CONSOLE_DEBUG   = BIT(3, U),    /* Use debug device. */
+    CONSOLE_RING    = BIT(4, U),    /* Use console ring. */
+    CONSOLE_DEFAULT = CONSOLE_SERIAL | CONSOLE_PV | CONSOLE_VIDEO |
+                      CONSOLE_DEBUG,
+    CONSOLE_ALL     = CONSOLE_DEFAULT | CONSOLE_RING,
+};
+
+static void console_puts(const char *str, size_t len, unsigned int flags);
+
 /* console: comma-separated list of console outputs. */
 static char __initdata opt_console[30] = OPT_CONSOLE_STR;
 string_param("console", opt_console);
@@ -338,8 +352,6 @@  static bool console_locks_busted;
 
 static void conring_puts(const char *str, size_t len)
 {
-    ASSERT(rspin_is_locked(&console_lock));
-
     while ( len-- )
         conring[CONRING_IDX_MASK(conringp++)] = *str++;
 
@@ -432,9 +444,6 @@  void console_serial_puts(const char *s, size_t nr)
         serial_steal_fn(s, nr);
     else
         serial_puts(sercon_handle, s, nr);
-
-    /* Copy all serial output into PV console */
-    pv_console_puts(s, nr);
 }
 
 static void cf_check dump_console_ring_key(unsigned char key)
@@ -468,8 +477,7 @@  static void cf_check dump_console_ring_key(unsigned char key)
         c += len;
     }
 
-    console_serial_puts(buf, sofar);
-    video_puts(buf, sofar);
+    console_puts(buf, sofar, CONSOLE_SERIAL | CONSOLE_VIDEO | CONSOLE_PV);
 
     free_xenheap_pages(buf, order);
 }
@@ -618,11 +626,61 @@  static inline void xen_console_write_debug_port(const char *buf, size_t len)
 }
 #endif
 
+static inline void console_debug_puts(const char *str, size_t len)
+{
+#ifdef CONFIG_X86
+    if ( opt_console_xen )
+    {
+        if ( xen_guest )
+            xen_hypercall_console_write(str, len);
+        else
+            xen_console_write_debug_port(str, len);
+    }
+#endif
+}
+
+/*
+ * Write buffer to all enabled console devices.
+ *
+ * That will handle all possible scenarios working w/ console
+ * - physical console (serial console, VGA console (x86 only));
+ * - PV console;
+ * - debug console (x86 only): debug I/O port or __HYPERVISOR_console_io
+ *   hypercall;
+ * - console ring.
+ */
+static void console_puts(const char *str, size_t len, unsigned int flags)
+{
+    ASSERT(rspin_is_locked(&console_lock));
+
+    if ( flags & CONSOLE_SERIAL )
+        console_serial_puts(str, len);
+
+    if ( flags & CONSOLE_PV )
+        pv_console_puts(str, len);
+
+    if ( flags & CONSOLE_VIDEO )
+        video_puts(str, len);
+
+    if ( flags & CONSOLE_DEBUG )
+        console_debug_puts(str, len);
+
+    if ( flags & CONSOLE_RING )
+        conring_puts(str, len);
+}
+
+static inline void __putstr(const char *str)
+{
+    console_puts(str, strlen(str), CONSOLE_ALL);
+}
+
 static long guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer,
                                 unsigned int count)
 {
     char kbuf[128];
     unsigned int kcount = 0;
+    unsigned int flags = opt_console_to_ring
+                         ? CONSOLE_ALL : CONSOLE_DEFAULT;
     struct domain *cd = current->domain;
 
     while ( count > 0 )
@@ -640,23 +698,7 @@  static long guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer,
         {
             /* Use direct console output as it could be interactive */
             nrspin_lock_irq(&console_lock);
-
-            console_serial_puts(kbuf, kcount);
-            video_puts(kbuf, kcount);
-
-#ifdef CONFIG_X86
-            if ( opt_console_xen )
-            {
-                if ( xen_guest )
-                    xen_hypercall_console_write(kbuf, kcount);
-                else
-                    xen_console_write_debug_port(kbuf, kcount);
-            }
-#endif
-
-            if ( opt_console_to_ring )
-                conring_puts(kbuf, kcount);
-
+            console_puts(kbuf, kcount, flags);
             nrspin_unlock_irq(&console_lock);
         }
         else
@@ -757,28 +799,6 @@  long do_console_io(
  * *****************************************************
  */
 
-static void __putstr(const char *str)
-{
-    size_t len = strlen(str);
-
-    ASSERT(rspin_is_locked(&console_lock));
-
-    console_serial_puts(str, len);
-    video_puts(str, len);
-
-#ifdef CONFIG_X86
-    if ( opt_console_xen )
-    {
-        if ( xen_guest )
-            xen_hypercall_console_write(str, len);
-        else
-            xen_console_write_debug_port(str, len);
-    }
-#endif
-
-    conring_puts(str, len);
-}
-
 static int printk_prefix_check(char *p, char **pp)
 {
     int loglvl = -1;