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>

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);

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

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.