[PATCH v3 05/24] xen/console: introduce consoled_is_enabled()

[Denis Mukhin via B4 Relay <devnull+dmukhin.ford.com@xxxxxxxxxx>]

From: Denis Mukhin <dmukhin@xxxxxxxx>

There are few places which check pv_shim console under CONFIG_PV_SHIM in xen
console driver. Instead of #ifdef-ing, use new consoled_is_enabled() to
customize the logic.

Header file now can be included w/o CONFIG_X86.

Signature of consoled_guest_{rx,tx} has changed so the error can be logged.

Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
 xen/drivers/char/console.c  | 13 +++++--------
 xen/drivers/char/consoled.c | 17 +++++++++++++----
 xen/include/xen/consoled.h  | 32 +++++++++++++++++++++++++++-----
 3 files changed, 45 insertions(+), 17 deletions(-)

diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 
4785f0e93a17e3ecba79a7813d2928f946abab8f..2d20a9d7531e069803eaf30ce79354b998c4a52f
 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -33,9 +33,9 @@
 #include <xen/pv_console.h>
 #include <asm/setup.h>
 #include <xen/sections.h>
+#include <xen/consoled.h>
 
 #ifdef CONFIG_X86
-#include <xen/consoled.h>
 #include <asm/guest.h>
 #endif
 #ifdef CONFIG_SBSA_VUART_CONSOLE
@@ -508,11 +508,9 @@ static void switch_serial_input(void)
             break;
         }
 
-#ifdef CONFIG_PV_SHIM
-        if ( next_rx == 1 )
+        if ( consoled_is_enabled() && next_rx == 1 )
             domid = get_initial_domain_id();
         else
-#endif
             domid = next_rx - 1;
         d = rcu_lock_domain_by_id(domid);
         if ( d )
@@ -563,10 +561,9 @@ static void __serial_rx(char c)
         rc = vpl011_rx_char_xen(d, c);
 #endif
 
-#ifdef CONFIG_X86
-    if ( pv_shim && pv_console )
-        consoled_guest_tx(c);
-#endif
+    if ( consoled_is_enabled() )
+        /* Deliver input to the PV shim console. */
+        rc = consoled_guest_tx(c);
 
     if ( rc )
         printk(KERN_ERR "d%pd: failed to process console input: %d\n", d, rc);
diff --git a/xen/drivers/char/consoled.c b/xen/drivers/char/consoled.c
index 
b415b632cecc0a80e161b701d7b70ba4f3cc5fb8..8704ec251eb19e9c1cdc5927f896aeb20cc5af1e
 100644
--- a/xen/drivers/char/consoled.c
+++ b/xen/drivers/char/consoled.c
@@ -43,13 +43,13 @@ struct xencons_interface *consoled_get_ring_addr(void)
 static char buf[BUF_SZ + 1];
 
 /* Receives characters from a domain's PV console */
-void consoled_guest_rx(void)
+int consoled_guest_rx(void)
 {
     size_t idx = 0;
     XENCONS_RING_IDX cons, prod;
 
     if ( !cons_ring )
-        return;
+        return -ENODEV;
 
     spin_lock(&rx_lock);
 
@@ -91,15 +91,17 @@ void consoled_guest_rx(void)
 
  out:
     spin_unlock(&rx_lock);
+
+    return 0;
 }
 
 /* Sends a character into a domain's PV console */
-void consoled_guest_tx(char c)
+int consoled_guest_tx(char c)
 {
     XENCONS_RING_IDX cons, prod;
 
     if ( !cons_ring )
-        return;
+        return -ENODEV;
 
     cons = ACCESS_ONCE(cons_ring->in_cons);
     prod = cons_ring->in_prod;
@@ -125,6 +127,13 @@ void consoled_guest_tx(char c)
  notify:
     /* Always notify the guest: prevents receive path from getting stuck. */
     pv_shim_inject_evtchn(pv_console_evtchn());
+
+    return 0;
+}
+
+bool consoled_is_enabled(void)
+{
+    return pv_shim && pv_console;
 }
 
 /*
diff --git a/xen/include/xen/consoled.h b/xen/include/xen/consoled.h
index 
bd7ab6329ee8a7c466484021247241ded8ed03c7..14e5e3284a86201919f0f70a8c2785609f35b15f
 100644
--- a/xen/include/xen/consoled.h
+++ b/xen/include/xen/consoled.h
@@ -1,14 +1,36 @@
-#ifndef __XEN_CONSOLED_H__
-#define __XEN_CONSOLED_H__
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef XEN__CONSOLED_H
+#define XEN__CONSOLED_H
 
 #include <public/io/console.h>
 
+#ifdef CONFIG_PV_SHIM
+
 void consoled_set_ring_addr(struct xencons_interface *ring);
 struct xencons_interface *consoled_get_ring_addr(void);
-void consoled_guest_rx(void);
-void consoled_guest_tx(char c);
+int consoled_guest_rx(void);
+int consoled_guest_tx(char c);
+bool consoled_is_enabled(void);
 
-#endif /* __XEN_CONSOLED_H__ */
+#else
+
+static inline int consoled_guest_rx(void)
+{
+    ASSERT_UNREACHABLE();
+    return 0;
+}
+
+static inline int consoled_guest_tx(char c)
+{
+    ASSERT_UNREACHABLE();
+    return 0;
+}
+
+#define consoled_is_enabled() ( false )
+
+#endif /* CONFIG_PV_SHIM */
+
+#endif /* XEN__CONSOLED_H */
 /*
  * Local variables:
  * mode: C

-- 
2.34.1