KVM: Portability: Move memory segmentation to x86.c

This patch moves the definition of segment_descriptor_64 for AMD64 and
EM64T from kvm_main.c to segment_descriptor.h. It also adds a proper
#ifndef...#define...#endif around that header file.
The implementation of segment_base is moved from kvm_main.c to x86.c.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

3 files changed, 45 insertions, 42 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index c632e3a3b51..cf163bddfbd 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -18,7 +18,6 @@
 #include "kvm.h"
 #include "x86.h"
 #include "x86_emulate.h"
-#include "segment_descriptor.h"
 #include "irq.h"
 
 #include <linux/kvm.h>
@@ -104,50 +103,9 @@ static struct dentry *debugfs_dir;
 #define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)
 #define EFER_RESERVED_BITS 0xfffffffffffff2fe
 
-#ifdef CONFIG_X86_64
-/* LDT or TSS descriptor in the GDT. 16 bytes. */
-struct segment_descriptor_64 {
-        struct segment_descriptor s;
-        u32 base_higher;
-        u32 pad_zero;
-};
-
-#endif
-
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
                            unsigned long arg);
 
-unsigned long segment_base(u16 selector)
-{
-        struct descriptor_table gdt;
-        struct segment_descriptor *d;
-        unsigned long table_base;
-        unsigned long v;
-
-        if (selector == 0)
-                return 0;
-
-        asm("sgdt %0" : "=m"(gdt));
-        table_base = gdt.base;
-
-        if (selector & 4) {           /* from ldt */
-                u16 ldt_selector;
-
-                asm("sldt %0" : "=g"(ldt_selector));
-                table_base = segment_base(ldt_selector);
-        }
-        d = (struct segment_descriptor *)(table_base + (selector & ~7));
-        v = d->base_low | ((unsigned long)d->base_mid << 16) |
-                ((unsigned long)d->base_high << 24);
-#ifdef CONFIG_X86_64
-        if (d->system == 0 && (d->type == 2 || d->type == 9 || d->type == 11))
-                v |= ((unsigned long) \
-                      ((struct segment_descriptor_64 *)d)->base_higher) << 32;
-#endif
-        return v;
-}
-EXPORT_SYMBOL_GPL(segment_base);
-
 static inline int valid_vcpu(int n)
 {
         return likely(n >= 0 && n < KVM_MAX_VCPUS);
diff --git a/drivers/kvm/segment_descriptor.h b/drivers/kvm/segment_descriptor.h
index 71fdf458619..56fc4c87338 100644
--- a/drivers/kvm/segment_descriptor.h
+++ b/drivers/kvm/segment_descriptor.h
@@ -1,3 +1,6 @@
+#ifndef __SEGMENT_DESCRIPTOR_H
+#define __SEGMENT_DESCRIPTOR_H
+
 struct segment_descriptor {
         u16 limit_low;
         u16 base_low;
@@ -14,4 +17,13 @@ struct segment_descriptor {
         u8  base_high;
 } __attribute__((packed));
 
+#ifdef CONFIG_X86_64
+/* LDT or TSS descriptor in the GDT. 16 bytes. */
+struct segment_descriptor_64 {
+        struct segment_descriptor s;
+        u32 base_higher;
+        u32 pad_zero;
+};
 
+#endif
+#endif
diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
index b84cb6707f7..5a959220410 100644
--- a/drivers/kvm/x86.c
+++ b/drivers/kvm/x86.c
@@ -16,16 +16,49 @@
 
 #include "kvm.h"
 #include "x86.h"
+#include "segment_descriptor.h"
 #include "irq.h"
 
 #include <linux/kvm.h>
 #include <linux/fs.h>
 #include <linux/vmalloc.h>
+#include <linux/module.h>
 
 #include <asm/uaccess.h>
 
 #define MAX_IO_MSRS 256
 
+unsigned long segment_base(u16 selector)
+{
+        struct descriptor_table gdt;
+        struct segment_descriptor *d;
+        unsigned long table_base;
+        unsigned long v;
+
+        if (selector == 0)
+                return 0;
+
+        asm("sgdt %0" : "=m"(gdt));
+        table_base = gdt.base;
+
+        if (selector & 4) {           /* from ldt */
+                u16 ldt_selector;
+
+                asm("sldt %0" : "=g"(ldt_selector));
+                table_base = segment_base(ldt_selector);
+        }
+        d = (struct segment_descriptor *)(table_base + (selector & ~7));
+        v = d->base_low | ((unsigned long)d->base_mid << 16) |
+                ((unsigned long)d->base_high << 24);
+#ifdef CONFIG_X86_64
+        if (d->system == 0 && (d->type == 2 || d->type == 9 || d->type == 11))
+                v |= ((unsigned long) \
+                      ((struct segment_descriptor_64 *)d)->base_higher) << 32;
+#endif
+        return v;
+}
+EXPORT_SYMBOL_GPL(segment_base);
+
 /*
  * List of msr numbers which we expose to userspace through KVM_GET_MSRS
  * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.