[PATCH v4 1/2] x86/vtx: add LBR_SELECT to the list of LBR MSRs

[Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>]

This MSR exists since Nehalem and is actively used by Linux, for instance,
to improve sampling efficiency.

Signed-off-by: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>
---
New patch in v4 as suggested by Andrew.
---
 xen/arch/x86/hvm/vmx/vmx.c      | 7 +++++--
 xen/include/asm-x86/msr-index.h | 6 +++++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 835b905..5a4ca35 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2915,14 +2915,16 @@ static const struct lbr_info {
 }, nh_lbr[] = {
     { MSR_IA32_LASTINTFROMIP,       1 },
     { MSR_IA32_LASTINTTOIP,         1 },
-    { MSR_C2_LASTBRANCH_TOS,        1 },
+    { MSR_NHL_LBR_SELECT,           1 },
+    { MSR_NHL_LASTBRANCH_TOS,       1 },
     { MSR_P4_LASTBRANCH_0_FROM_LIP, NUM_MSR_P4_LASTBRANCH_FROM_TO },
     { MSR_P4_LASTBRANCH_0_TO_LIP,   NUM_MSR_P4_LASTBRANCH_FROM_TO },
     { 0, 0 }
 }, sk_lbr[] = {
     { MSR_IA32_LASTINTFROMIP,       1 },
     { MSR_IA32_LASTINTTOIP,         1 },
-    { MSR_SKL_LASTBRANCH_TOS,       1 },
+    { MSR_NHL_LBR_SELECT,           1 },
+    { MSR_NHL_LASTBRANCH_TOS,       1 },
     { MSR_SKL_LASTBRANCH_0_FROM_IP, NUM_MSR_SKL_LASTBRANCH },
     { MSR_SKL_LASTBRANCH_0_TO_IP,   NUM_MSR_SKL_LASTBRANCH },
     { MSR_SKL_LASTBRANCH_0_INFO,    NUM_MSR_SKL_LASTBRANCH },
@@ -2937,6 +2939,7 @@ static const struct lbr_info {
 }, gm_lbr[] = {
     { MSR_IA32_LASTINTFROMIP,       1 },
     { MSR_IA32_LASTINTTOIP,         1 },
+    { MSR_GM_LBR_SELECT,            1 },
     { MSR_GM_LASTBRANCH_TOS,        1 },
     { MSR_GM_LASTBRANCH_0_FROM_IP,  NUM_MSR_GM_LASTBRANCH_FROM_TO },
     { MSR_GM_LASTBRANCH_0_TO_IP,    NUM_MSR_GM_LASTBRANCH_FROM_TO },
diff --git a/xen/include/asm-x86/msr-index.h b/xen/include/asm-x86/msr-index.h
index 43d26ef..25c4308 100644
--- a/xen/include/asm-x86/msr-index.h
+++ b/xen/include/asm-x86/msr-index.h
@@ -606,14 +606,18 @@
 #define NUM_MSR_C2_LASTBRANCH_FROM_TO  4
 #define NUM_MSR_ATOM_LASTBRANCH_FROM_TO        8
 
+/* Nehalem (and newer) last-branch recording */
+#define MSR_NHL_LBR_SELECT             0x000001c8
+#define MSR_NHL_LASTBRANCH_TOS         0x000001c9
+
 /* Skylake (and newer) last-branch recording */
-#define MSR_SKL_LASTBRANCH_TOS         0x000001c9
 #define MSR_SKL_LASTBRANCH_0_FROM_IP   0x00000680
 #define MSR_SKL_LASTBRANCH_0_TO_IP     0x000006c0
 #define MSR_SKL_LASTBRANCH_0_INFO      0x00000dc0
 #define NUM_MSR_SKL_LASTBRANCH         32
 
 /* Goldmont last-branch recording */
+#define MSR_GM_LBR_SELECT              0x000001c8
 #define MSR_GM_LASTBRANCH_TOS          0x000001c9
 #define MSR_GM_LASTBRANCH_0_FROM_IP    0x00000680
 #define MSR_GM_LASTBRANCH_0_TO_IP      0x000006c0
-- 
2.7.4