References: FATE#309900

# HG changeset patch
# User Andre Przywara <andre.przywara@amd.com>
# Date 1303116553 -3600
# Node ID bf7afd48339a18cd86d89337f3c055045fb78d3b
# Parent  1276926e3795b11ef6ac2f59df900d8e0ba9f54b
svm: add bit definitions for SVM DecodeAssist

Chapter 15.33 of recent APM Vol.2 manuals describe some additions
to SVM called DecodeAssist. Add the newly added fields to the VMCB
structure and name the associated CPUID bit.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>

# HG changeset patch
# User Keir Fraser <keir@xen.org>
# Date 1303117802 -3600
# Node ID 381ab77db71a4739b8a4f4fdad4ef3504999f998
# Parent  e324c4d1dd6eeb9417fec513640ca795bd0f5dd4
svm: decode-assists feature must depend on nextrip feature.

...since the decode-assist fast paths assume nextrip vmcb field is
valid.

Signed-off-by: Keir Fraser <keir@xen.org>

Index: xen-4.1.2-testing/xen/arch/x86/hvm/svm/svm.c
===================================================================
--- xen-4.1.2-testing.orig/xen/arch/x86/hvm/svm/svm.c
+++ xen-4.1.2-testing/xen/arch/x86/hvm/svm/svm.c
@@ -928,11 +928,16 @@ struct hvm_function_table * __init start
 
     printk("SVM: Supported advanced features:\n");
 
+    /* DecodeAssists fast paths assume nextrip is valid for fast rIP update. */
+    if ( !cpu_has_svm_nrips )
+        clear_bit(SVM_FEATURE_DECODEASSISTS, &svm_feature_flags);
+
 #define P(p,s) if ( p ) { printk(" - %s\n", s); printed = 1; }
     P(cpu_has_svm_npt, "Nested Page Tables (NPT)");
     P(cpu_has_svm_lbrv, "Last Branch Record (LBR) Virtualisation");
     P(cpu_has_svm_nrips, "Next-RIP Saved on #VMEXIT");
     P(cpu_has_svm_cleanbits, "VMCB Clean Bits");
+    P(cpu_has_svm_decode, "DecodeAssists");
     P(cpu_has_pause_filter, "Pause-Intercept Filter");
 #undef P
 
Index: xen-4.1.2-testing/xen/include/asm-x86/hvm/svm/svm.h
===================================================================
--- xen-4.1.2-testing.orig/xen/include/asm-x86/hvm/svm/svm.h
+++ xen-4.1.2-testing/xen/include/asm-x86/hvm/svm/svm.h
@@ -80,6 +80,7 @@ extern u32 svm_feature_flags;
 #define cpu_has_svm_svml      cpu_has_svm_feature(SVM_FEATURE_SVML)
 #define cpu_has_svm_nrips     cpu_has_svm_feature(SVM_FEATURE_NRIPS)
 #define cpu_has_svm_cleanbits cpu_has_svm_feature(SVM_FEATURE_VMCBCLEAN)
+#define cpu_has_svm_decode    cpu_has_svm_feature(SVM_FEATURE_DECODEASSISTS)
 #define cpu_has_pause_filter  cpu_has_svm_feature(SVM_FEATURE_PAUSEFILTER)
 
 #endif /* __ASM_X86_HVM_SVM_H__ */
Index: xen-4.1.2-testing/xen/include/asm-x86/hvm/svm/vmcb.h
===================================================================
--- xen-4.1.2-testing.orig/xen/include/asm-x86/hvm/svm/vmcb.h
+++ xen-4.1.2-testing/xen/include/asm-x86/hvm/svm/vmcb.h
@@ -432,7 +432,9 @@ struct vmcb_struct {
     vmcbcleanbits_t cleanbits;  /* offset 0xC0 */
     u32 res09;                  /* offset 0xC4 */
     u64 nextrip;                /* offset 0xC8 */
-    u64 res10a[102];            /* offset 0xD0 pad to save area */
+    u8  guest_ins_len;          /* offset 0xD0 */
+    u8  guest_ins[15];          /* offset 0xD1 */
+    u64 res10a[100];            /* offset 0xE0 pad to save area */
 
     svm_segment_register_t es;  /* offset 1024 - cleanbit 8 */
     svm_segment_register_t cs;  /* cleanbit 8 */