x86/vtx: add LBR_SELECT to the list of LBR MSRs

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

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-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 b52824677e9f5dde10be7c4a584859ae28ae2ca3..8e0aa976c22f5f916273fb700fc7895dd2827f97 100644 (file)
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2898,14 +2898,16 @@ 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 },
@@ -2917,10 +2919,19 @@ static const struct lbr_info {
     { MSR_C2_LASTBRANCH_0_FROM_IP,  NUM_MSR_ATOM_LASTBRANCH_FROM_TO },
     { MSR_C2_LASTBRANCH_0_TO_IP,    NUM_MSR_ATOM_LASTBRANCH_FROM_TO },
     { 0, 0 }
+}, sm_lbr[] = {
+    { MSR_IA32_LASTINTFROMIP,       1 },
+    { MSR_IA32_LASTINTTOIP,         1 },
+    { MSR_SM_LBR_SELECT,            1 },
+    { MSR_SM_LASTBRANCH_TOS,        1 },
+    { MSR_C2_LASTBRANCH_0_FROM_IP,  NUM_MSR_ATOM_LASTBRANCH_FROM_TO },
+    { MSR_C2_LASTBRANCH_0_TO_IP,    NUM_MSR_ATOM_LASTBRANCH_FROM_TO },
+    { 0, 0 }
 }, gm_lbr[] = {
     { MSR_IA32_LASTINTFROMIP,       1 },
     { MSR_IA32_LASTINTTOIP,         1 },
-    { MSR_GM_LASTBRANCH_TOS,        1 },
+    { MSR_SM_LBR_SELECT,            1 },
+    { MSR_SM_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 },
     { 0, 0 }
@@ -2974,6 +2985,7 @@ static const struct lbr_info *last_branch_msr_get(void)
             return sk_lbr;
         /* Atom */
         case 0x1c: case 0x26: case 0x27: case 0x35: case 0x36:
+            return at_lbr;
         /* Silvermont */
         case 0x37: case 0x4a: case 0x4d: case 0x5a: case 0x5d:
         /* Xeon Phi Knights Landing */
@@ -2982,7 +2994,7 @@ static const struct lbr_info *last_branch_msr_get(void)
         case 0x85:
         /* Airmont */
         case 0x4c:
-            return at_lbr;
+            return sm_lbr;
         /* Goldmont */
         case 0x5c: case 0x5f:
             return gm_lbr;

diff --git a/xen/include/asm-x86/msr-index.h b/xen/include/asm-x86/msr-index.h
index f2e34dd22bd8e496aa3681cd16f6eb1e9ffc9760..bd3a3a1e7f5ca457c6b41f9fc53a0d3fb076f046 100644 (file)
--- a/xen/include/asm-x86/msr-index.h
+++ b/xen/include/asm-x86/msr-index.h
@@ -603,15 +603,21 @@
 #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
 
+/* Silvermont (and newer) last-branch recording */
+#define MSR_SM_LBR_SELECT              0x000001c8
+#define MSR_SM_LASTBRANCH_TOS          0x000001c9
+
 /* Goldmont last-branch recording */
-#define MSR_GM_LASTBRANCH_TOS          0x000001c9
 #define MSR_GM_LASTBRANCH_0_FROM_IP    0x00000680
 #define MSR_GM_LASTBRANCH_0_TO_IP      0x000006c0
 #define NUM_MSR_GM_LASTBRANCH_FROM_TO  32