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From: Igor Druzhinin <igor.druzhinin@citrix.com>
To: <xen-devel@lists.xenproject.org>
Cc: <jbeulich@suse.com>, <andrew.cooper3@citrix.com>,
	<roger.pau@citrix.com>, <wl@xen.org>, <jun.nakajima@intel.com>,
	<kevin.tian@intel.com>,
	"Igor Druzhinin" <igor.druzhinin@citrix.com>
Subject: [PATCH v4 1/2] x86/vtx: add LBR_SELECT to the list of LBR MSRs
Date: Wed, 14 Apr 2021 05:40:21 +0100	[thread overview]
Message-ID: <1618375222-9283-1-git-send-email-igor.druzhinin@citrix.com> (raw)

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

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
---
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



             reply	other threads:[~2021-04-14  4:40 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-14  4:40 Igor Druzhinin [this message]
2021-04-14  4:40 ` [PATCH v4 2/2] x86/intel: insert Ice Lake-SP and Ice Lake-D model numbers Igor Druzhinin
2021-04-14 12:24   ` Jan Beulich
2021-04-14 11:41 ` [PATCH v4 1/2] x86/vtx: add LBR_SELECT to the list of LBR MSRs Jan Beulich
2021-04-14 23:13   ` Igor Druzhinin
2021-04-15  9:01     ` Jan Beulich

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