x86/vmx: Shorten vmx_{get,set}_segment_register() for user segments

The x86_segment enumeration matches hardware SReg encoding, which can be used
to calculate the appropriate VMCS fields, rather than open coding every
instance.

This reduces the size of the switch statement, and the number of embedded BUG
frames from the __vm{read,write}() calls.  In the unlikely case that a call
does fault, the field can unambiguously be retrieved from the GPR state
printed.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 7b2c50cf447b02f15bb1c5a9d23bee7475c9caea..47de37585e6ed0bc6f36e8bdf8ce6073937b2851 100644 (file)
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -969,41 +969,11 @@ void vmx_get_segment_register(struct vcpu *v, enum x86_segment seg,
 
     switch ( seg )
     {
-    case x86_seg_cs:
-        __vmread(GUEST_CS_SELECTOR, &sel);
-        __vmread(GUEST_CS_LIMIT,    &limit);
-        __vmread(GUEST_CS_BASE,     &reg->base);
-        __vmread(GUEST_CS_AR_BYTES, &attr);
-        break;
-    case x86_seg_ds:
-        __vmread(GUEST_DS_SELECTOR, &sel);
-        __vmread(GUEST_DS_LIMIT,    &limit);
-        __vmread(GUEST_DS_BASE,     &reg->base);
-        __vmread(GUEST_DS_AR_BYTES, &attr);
-        break;
-    case x86_seg_es:
-        __vmread(GUEST_ES_SELECTOR, &sel);
-        __vmread(GUEST_ES_LIMIT,    &limit);
-        __vmread(GUEST_ES_BASE,     &reg->base);
-        __vmread(GUEST_ES_AR_BYTES, &attr);
-        break;
-    case x86_seg_fs:
-        __vmread(GUEST_FS_SELECTOR, &sel);
-        __vmread(GUEST_FS_LIMIT,    &limit);
-        __vmread(GUEST_FS_BASE,     &reg->base);
-        __vmread(GUEST_FS_AR_BYTES, &attr);
-        break;
-    case x86_seg_gs:
-        __vmread(GUEST_GS_SELECTOR, &sel);
-        __vmread(GUEST_GS_LIMIT,    &limit);
-        __vmread(GUEST_GS_BASE,     &reg->base);
-        __vmread(GUEST_GS_AR_BYTES, &attr);
-        break;
-    case x86_seg_ss:
-        __vmread(GUEST_SS_SELECTOR, &sel);
-        __vmread(GUEST_SS_LIMIT,    &limit);
-        __vmread(GUEST_SS_BASE,     &reg->base);
-        __vmread(GUEST_SS_AR_BYTES, &attr);
+    case x86_seg_es ... x86_seg_gs:
+        __vmread(GUEST_SEG_SELECTOR(seg), &sel);
+        __vmread(GUEST_SEG_LIMIT(seg),    &limit);
+        __vmread(GUEST_SEG_BASE(seg),     &reg->base);
+        __vmread(GUEST_SEG_AR_BYTES(seg), &attr);
         break;
     case x86_seg_tr:
         __vmread(GUEST_TR_SELECTOR, &sel);
@@ -1133,41 +1103,11 @@ static void vmx_set_segment_register(struct vcpu *v, enum x86_segment seg,
 
     switch ( seg )
     {
-    case x86_seg_cs:
-        __vmwrite(GUEST_CS_SELECTOR, sel);
-        __vmwrite(GUEST_CS_LIMIT, limit);
-        __vmwrite(GUEST_CS_BASE, base);
-        __vmwrite(GUEST_CS_AR_BYTES, attr);
-        break;
-    case x86_seg_ds:
-        __vmwrite(GUEST_DS_SELECTOR, sel);
-        __vmwrite(GUEST_DS_LIMIT, limit);
-        __vmwrite(GUEST_DS_BASE, base);
-        __vmwrite(GUEST_DS_AR_BYTES, attr);
-        break;
-    case x86_seg_es:
-        __vmwrite(GUEST_ES_SELECTOR, sel);
-        __vmwrite(GUEST_ES_LIMIT, limit);
-        __vmwrite(GUEST_ES_BASE, base);
-        __vmwrite(GUEST_ES_AR_BYTES, attr);
-        break;
-    case x86_seg_fs:
-        __vmwrite(GUEST_FS_SELECTOR, sel);
-        __vmwrite(GUEST_FS_LIMIT, limit);
-        __vmwrite(GUEST_FS_BASE, base);
-        __vmwrite(GUEST_FS_AR_BYTES, attr);
-        break;
-    case x86_seg_gs:
-        __vmwrite(GUEST_GS_SELECTOR, sel);
-        __vmwrite(GUEST_GS_LIMIT, limit);
-        __vmwrite(GUEST_GS_BASE, base);
-        __vmwrite(GUEST_GS_AR_BYTES, attr);
-        break;
-    case x86_seg_ss:
-        __vmwrite(GUEST_SS_SELECTOR, sel);
-        __vmwrite(GUEST_SS_LIMIT, limit);
-        __vmwrite(GUEST_SS_BASE, base);
-        __vmwrite(GUEST_SS_AR_BYTES, attr);
+    case x86_seg_es ... x86_seg_gs:
+        __vmwrite(GUEST_SEG_SELECTOR(seg), sel);
+        __vmwrite(GUEST_SEG_LIMIT(seg),    limit);
+        __vmwrite(GUEST_SEG_BASE(seg),     base);
+        __vmwrite(GUEST_SEG_AR_BYTES(seg), attr);
         break;
     case x86_seg_tr:
         __vmwrite(GUEST_TR_SELECTOR, sel);

diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h b/xen/include/asm-x86/hvm/vmx/vmcs.h
index 997f4f55fa78dce8ffad518d302ba1b7cfc98579..894093d629fb68a5d9f93567190be836fee3b38b 100644 (file)
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
@@ -420,6 +420,7 @@ enum vmcs_field {
     VIRTUAL_PROCESSOR_ID            = 0x00000000,
     POSTED_INTR_NOTIFICATION_VECTOR = 0x00000002,
     EPTP_INDEX                      = 0x00000004,
+#define GUEST_SEG_SELECTOR(sel) (GUEST_ES_SELECTOR + (sel) * 2) /* ES ... GS */
     GUEST_ES_SELECTOR               = 0x00000800,
     GUEST_CS_SELECTOR               = 0x00000802,
     GUEST_SS_SELECTOR               = 0x00000804,
@@ -496,6 +497,7 @@ enum vmcs_field {
     IDT_VECTORING_ERROR_CODE        = 0x0000440a,
     VM_EXIT_INSTRUCTION_LEN         = 0x0000440c,
     VMX_INSTRUCTION_INFO            = 0x0000440e,
+#define GUEST_SEG_LIMIT(sel) (GUEST_ES_LIMIT + (sel) * 2) /* ES ... GS */
     GUEST_ES_LIMIT                  = 0x00004800,
     GUEST_CS_LIMIT                  = 0x00004802,
     GUEST_SS_LIMIT                  = 0x00004804,
@@ -506,6 +508,7 @@ enum vmcs_field {
     GUEST_TR_LIMIT                  = 0x0000480e,
     GUEST_GDTR_LIMIT                = 0x00004810,
     GUEST_IDTR_LIMIT                = 0x00004812,
+#define GUEST_SEG_AR_BYTES(sel) (GUEST_ES_AR_BYTES + (sel) * 2) /* ES ... GS */
     GUEST_ES_AR_BYTES               = 0x00004814,
     GUEST_CS_AR_BYTES               = 0x00004816,
     GUEST_SS_AR_BYTES               = 0x00004818,
@@ -531,6 +534,7 @@ enum vmcs_field {
     GUEST_CR0                       = 0x00006800,
     GUEST_CR3                       = 0x00006802,
     GUEST_CR4                       = 0x00006804,
+#define GUEST_SEG_BASE(sel) (GUEST_ES_BASE + (sel) * 2) /* ES ... GS */
     GUEST_ES_BASE                   = 0x00006806,
     GUEST_CS_BASE                   = 0x00006808,
     GUEST_SS_BASE                   = 0x0000680a,