x86: prepare 64-bit architecture initialization for paravirt

This patch prepares the x86_64 architecture initialization for
paravirt. It requires a memory initialization step, which is done
by implementing 64-bit version for machine_specific_memory_setup,
and putting an ARCH_SETUP hook, for guest-dependent initialization.
This last step is done akin to i386

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 27 insertions, 1 deletions

diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index f2b131ef844e..8dd110d93e73 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -39,6 +39,7 @@
 #include <linux/dmi.h>
 #include <linux/dma-mapping.h>
 #include <linux/ctype.h>
+#include <linux/uaccess.h>
 
 #include <asm/mtrr.h>
 #include <asm/uaccess.h>
@@ -62,6 +63,12 @@
 #include <asm/mce.h>
 #include <asm/ds.h>
 
+#ifdef CONFIG_PARAVIRT
+#include <asm/paravirt.h>
+#else
+#define ARCH_SETUP
+#endif
+
 /*
  * Machine setup..
  */
@@ -246,6 +253,16 @@ static void discover_ebda(void)
          * 4K EBDA area at 0x40E
          */
         ebda_addr = *(unsigned short *)__va(EBDA_ADDR_POINTER);
+        /*
+         * There can be some situations, like paravirtualized guests,
+         * in which there is no available ebda information. In such
+         * case, just skip it
+         */
+        if (!ebda_addr) {
+                ebda_size = 0;
+                return;
+        }
+
         ebda_addr <<= 4;
 
         ebda_size = *(unsigned short *)__va(ebda_addr);
@@ -259,6 +276,12 @@ static void discover_ebda(void)
                 ebda_size = 64*1024;
 }
 
+/* Overridden in paravirt.c if CONFIG_PARAVIRT */
+void __attribute__((weak)) memory_setup(void)
+{
+       machine_specific_memory_setup();
+}
+
 void __init setup_arch(char **cmdline_p)
 {
         unsigned i;
@@ -276,7 +299,10 @@ void __init setup_arch(char **cmdline_p)
         rd_prompt = ((boot_params.hdr.ram_size & RAMDISK_PROMPT_FLAG) != 0);
         rd_doload = ((boot_params.hdr.ram_size & RAMDISK_LOAD_FLAG) != 0);
 #endif
-        setup_memory_region();
+
+        ARCH_SETUP
+
+        memory_setup();
         copy_edd();
 
         if (!boot_params.hdr.root_flags)