[XTF 3/4] Enabled serial writing for hvm guests

[Pawel Wieczorkiewicz]

From: Paul Semel <phen...@amazon.de>

setup.c: PV console writing is not working in Xen 4.2 for hvm
guests, so we make xtf write to COM1 serial port to get its output

Signed-off-by: Paul Semel <phen...@amazon.de>
Signed-off-by: Pawel Wieczorkiewicz <wipa...@amazon.de>
---
 arch/x86/setup.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/x86/setup.c b/arch/x86/setup.c
index 3c84e96..f6fa4df 100644
--- a/arch/x86/setup.c
+++ b/arch/x86/setup.c
@@ -238,6 +238,13 @@ static void qemu_console_write(const char *buf, size_t len)
                  : "d" (0x12));
 }
 
+static void com1_write(const char *buf, size_t len)
+{
+    asm volatile("rep; outsb"
+                 : "+S" (buf), "+c" (len)
+                 : "d" (0x3f8));
+}
+
 static void xen_console_write(const char *buf, size_t len)
 {
     hypercall_console_write(buf, len);
@@ -246,7 +253,14 @@ static void xen_console_write(const char *buf, size_t len)
 void arch_setup(void)
 {
     if ( IS_DEFINED(CONFIG_HVM) && !pvh_start_info )
+    {
         register_console_callback(qemu_console_write);
+    }
+
+    if ( IS_DEFINED(CONFIG_HVM) )
+    {
+        register_console_callback(com1_write);
+    }
 
     register_console_callback(xen_console_write);
 
-- 
2.16.6




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