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From: Igor Druzhinin <igor.druzhinin@citrix.com>
To: <xen-devel@lists.xenproject.org>
Cc: <jun.nakajima@intel.com>, <kevin.tian@intel.com>,
	<jbeulich@suse.com>, <andrew.cooper3@citrix.com>,
	<roger.pau@citrix.com>, <wl@xen.org>,
	"Igor Druzhinin" <igor.druzhinin@citrix.com>
Subject: [PATCH v5 1/2] x86/vtx: add LBR_SELECT to the list of LBR MSRs
Date: Thu, 15 Apr 2021 11:04:21 +0100	[thread overview]
Message-ID: <1618481062-16094-1-git-send-email-igor.druzhinin@citrix.com> (raw)

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>
---
Changes in v5:
- added Silvermont+ LBR_SELECT support

New patch in v4 as suggested by Andrew.
---
 xen/arch/x86/hvm/vmx/vmx.c      | 20 ++++++++++++++++----
 xen/include/asm-x86/msr-index.h | 10 ++++++++--
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 835b905..30c6a57 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 },
@@ -2934,10 +2936,19 @@ 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 }
@@ -2991,6 +3002,7 @@ 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 */
@@ -2999,7 +3011,7 @@ 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 43d26ef..020908f 100644
--- a/xen/include/asm-x86/msr-index.h
+++ b/xen/include/asm-x86/msr-index.h
@@ -606,15 +606,21 @@
 #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
-- 
2.7.4



             reply	other threads:[~2021-04-15 10:05 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-15 10:04 Igor Druzhinin [this message]
2021-04-15 10:04 ` [PATCH v5 2/2] x86/intel: insert Ice Lake-SP and Ice Lake-D model numbers Igor Druzhinin
2021-04-25  1:07   ` Tian, Kevin
2021-04-15 11:50 ` [PATCH v5 1/2] x86/vtx: add LBR_SELECT to the list of LBR MSRs Jan Beulich
2021-04-25  1:07 ` Tian, Kevin

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