[Xen-changelog] [xen staging] xen: support console_switching between Dom0 and DomUs on ARM

[patchbot@xxxxxxx]

commit 19afff14b4cb8f79afad20fa48507b04309eaf4c
Author:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
AuthorDate: Tue Nov 13 09:49:32 2018 -0800
Commit:     Julien Grall <julien.grall@xxxxxxx>
CommitDate: Wed Nov 14 19:34:48 2018 +0000

    xen: support console_switching between Dom0 and DomUs on ARM
    
    Today Ctrl-AAA is used to switch between Xen and Dom0. Extend the
    mechanism to allow for switching between Xen, Dom0, and any of the
    initial DomU created from Xen alongside Dom0 out of information provided
    via device tree.
    
    Rename xen_rx to console_rx to match the new behavior.
    
    Clarify existing comment about "notify the guest", making it clear that
    it is only about the hardware domain.
    
    Switching the console input to domUs started from Xen at boot is
    #ifdef'ed to 0 in this patch. The code will be enabled when
    vpl011_rx_char_xen is introduced. For now it is disabled for
    bisectability.
    
    Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
    CC: andrew.cooper3@xxxxxxxxxx
    CC: George.Dunlap@xxxxxxxxxxxxx
    CC: ian.jackson@xxxxxxxxxxxxx
    CC: jbeulich@xxxxxxxx
    CC: konrad.wilk@xxxxxxxxxx
    CC: tim@xxxxxxx
    CC: wei.liu2@xxxxxxxxxx
---
 xen/drivers/char/console.c | 82 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 68 insertions(+), 14 deletions(-)

diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 907aa97cd4..414d329c39 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -31,10 +31,13 @@
 #include <xen/early_printk.h>
 #include <xen/warning.h>
 #include <xen/pv_console.h>
+#include <asm/setup.h>
 
 #ifdef CONFIG_X86
 #include <xen/consoled.h>
 #include <asm/guest.h>
+#else
+#include <asm/vpl011.h>
 #endif
 
 /* console: comma-separated list of console outputs. */
@@ -391,31 +394,82 @@ static void dump_console_ring_key(unsigned char key)
     free_xenheap_pages(buf, order);
 }
 
-/* CTRL-<switch_char> switches input direction between Xen and DOM0. */
+/*
+ * CTRL-<switch_char> changes input direction, rotating among Xen, Dom0,
+ * and the DomUs started from Xen at boot.
+ */
 #define switch_code (opt_conswitch[0]-'a'+1)
-static int __read_mostly xen_rx = 1; /* FALSE => input passed to domain 0. */
+/*
+ * console_rx=0 => input to xen
+ * console_rx=1 => input to dom0
+ * console_rx=N => input to dom(N-1)
+ */
+static unsigned int __read_mostly console_rx = 0;
 
 static void switch_serial_input(void)
 {
-    static char *input_str[2] = { "DOM0", "Xen" };
-    xen_rx = !xen_rx;
-    printk("*** Serial input -> %s", input_str[xen_rx]);
+    if ( console_rx == max_init_domid + 1 )
+    {
+        console_rx = 0;
+        printk("*** Serial input to Xen");
+    }
+    else
+    {
+        console_rx++;
+        printk("*** Serial input to DOM%d", console_rx - 1);
+    }
+
     if ( switch_code )
-        printk(" (type 'CTRL-%c' three times to switch input to %s)",
-               opt_conswitch[0], input_str[!xen_rx]);
+        printk(" (type 'CTRL-%c' three times to switch input)",
+               opt_conswitch[0]);
     printk("\n");
 }
 
 static void __serial_rx(char c, struct cpu_user_regs *regs)
 {
-    if ( xen_rx )
+    switch ( console_rx )
+    {
+    case 0:
         return handle_keypress(c, regs);
 
-    /* Deliver input to guest buffer, unless it is already full. */
-    if ( (serial_rx_prod-serial_rx_cons) != SERIAL_RX_SIZE )
-        serial_rx_ring[SERIAL_RX_MASK(serial_rx_prod++)] = c;
-    /* Always notify the guest: prevents receive path from getting stuck. */
-    send_global_virq(VIRQ_CONSOLE);
+    case 1:
+        /*
+         * Deliver input to the hardware domain buffer, unless it is
+         * already full.
+         */
+        if ( (serial_rx_prod - serial_rx_cons) != SERIAL_RX_SIZE )
+            serial_rx_ring[SERIAL_RX_MASK(serial_rx_prod++)] = c;
+
+        /*
+         * Always notify the hardware domain: prevents receive path from
+         * getting stuck.
+         */
+        send_global_virq(VIRQ_CONSOLE);
+        break;
+
+#if 0
+    default:
+    {
+        struct domain *d = rcu_lock_domain_by_any_id(console_rx - 1);
+
+        /*
+         * If we have a properly initialized vpl011 console for the
+         * domain, without a full PV ring to Dom0 (in that case input
+         * comes from the PV ring), then send the character to it.
+         */
+        if ( d != NULL &&
+             !d->arch.vpl011.backend_in_domain &&
+             d->arch.vpl011.backend.xen != NULL )
+            vpl011_rx_char_xen(d, c);
+        else
+            printk("Cannot send chars to Dom%d: no UART available\n",
+                   console_rx - 1);
+
+        if ( d != NULL )
+            rcu_unlock_domain(d);
+    }
+#endif
+    }
 
 #ifdef CONFIG_X86
     if ( pv_shim && pv_console )
@@ -944,7 +998,7 @@ void __init console_endboot(void)
      * a useful 'how to switch' message.
      */
     if ( opt_conswitch[1] == 'x' )
-        xen_rx = !xen_rx;
+        console_rx = max_init_domid + 1;
 
     register_keyhandler('w', dump_console_ring_key,
                         "synchronously dump console ring buffer (dmesg)", 0);
--
generated by git-patchbot for /home/xen/git/xen.git#staging

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/xen-changelog