[tip:x86/xsave] x86/xsaves: Detect xsaves/xrstors feature

From: tip-bot for Fenghua Yu
Date: Fri May 30 2014 - 11:11:08 EST

Commit-ID: 6229ad278ca74acdbc8bd3a3d469322a3de91039
Gitweb: http://git.kernel.org/tip/6229ad278ca74acdbc8bd3a3d469322a3de91039
Author: Fenghua Yu <fenghua.yu@xxxxxxxxx>
AuthorDate: Thu, 29 May 2014 11:12:30 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Thu, 29 May 2014 14:24:28 -0700

x86/xsaves: Detect xsaves/xrstors feature

Detect the xsaveopt, xsavec, xgetbv, and xsaves features in processor extended
state enumberation sub-leaf (eax=0x0d, ecx=1):
Bit 00: XSAVEOPT is available
Bit 01: Supports XSAVEC and the compacted form of XRSTOR if set
Bit 02: Supports XGETBV with ECX = 1 if set
Bit 03: Supports XSAVES/XRSTORS and IA32_XSS if set

The above features are defined in the new word 10 in cpu features.

The IA32_XSS MSR (index DA0H) contains a state-component bitmap that specifies
the state components that software has enabled xsaves and xrstors to manage.
If the bit corresponding to a state component is clear in XCR0 | IA32_XSS,
xsaves and xrstors will not operate on that state component, regardless of
the value of the instruction mask.

Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1401387164-43416-3-git-send-email-fenghua.yu@xxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/cpufeature.h | 10 ++++++++--
arch/x86/include/uapi/asm/msr-index.h | 2 ++
arch/x86/kernel/cpu/common.c | 9 +++++++++
arch/x86/kernel/cpu/scattered.c | 1 -
4 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 2837b92..b82f951 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -8,7 +8,7 @@
#include <asm/required-features.h>
#endif

-#define NCAPINTS 10 /* N 32-bit words worth of info */
+#define NCAPINTS 11 /* N 32-bit words worth of info */
#define NBUGINTS 1 /* N 32-bit bug flags */

/*
@@ -180,7 +180,6 @@
#define X86_FEATURE_ARAT ( 7*32+ 1) /* Always Running APIC Timer */
#define X86_FEATURE_CPB ( 7*32+ 2) /* AMD Core Performance Boost */
#define X86_FEATURE_EPB ( 7*32+ 3) /* IA32_ENERGY_PERF_BIAS support */
-#define X86_FEATURE_XSAVEOPT ( 7*32+ 4) /* Optimized Xsave */
#define X86_FEATURE_PLN ( 7*32+ 5) /* Intel Power Limit Notification */
#define X86_FEATURE_PTS ( 7*32+ 6) /* Intel Package Thermal Status */
#define X86_FEATURE_DTHERM ( 7*32+ 7) /* Digital Thermal Sensor */
@@ -226,6 +225,12 @@
#define X86_FEATURE_AVX512ER ( 9*32+27) /* AVX-512 Exponential and Reciprocal */
#define X86_FEATURE_AVX512CD ( 9*32+28) /* AVX-512 Conflict Detection */

+/* Extended state features, CPUID level 0x0000000d:1 (eax), word 10 */
+#define X86_FEATURE_XSAVEOPT (10*32+ 0) /* XSAVEOPT */
+#define X86_FEATURE_XSAVEC (10*32+ 1) /* XSAVEC */
+#define X86_FEATURE_XGETBV1 (10*32+ 2) /* XGETBV with ECX = 1 */
+#define X86_FEATURE_XSAVES (10*32+ 3) /* XSAVES/XRSTORS */
+
/*
* BUG word(s)
*/
@@ -328,6 +333,7 @@ extern const char * const x86_power_flags[32];
#define cpu_has_x2apic boot_cpu_has(X86_FEATURE_X2APIC)
#define cpu_has_xsave boot_cpu_has(X86_FEATURE_XSAVE)
#define cpu_has_xsaveopt boot_cpu_has(X86_FEATURE_XSAVEOPT)
+#define cpu_has_xsaves boot_cpu_has(X86_FEATURE_XSAVES)
#define cpu_has_osxsave boot_cpu_has(X86_FEATURE_OSXSAVE)
#define cpu_has_hypervisor boot_cpu_has(X86_FEATURE_HYPERVISOR)
#define cpu_has_pclmulqdq boot_cpu_has(X86_FEATURE_PCLMULQDQ)
diff --git a/arch/x86/include/uapi/asm/msr-index.h b/arch/x86/include/uapi/asm/msr-index.h
index fcf2b3a..5cd1569 100644
--- a/arch/x86/include/uapi/asm/msr-index.h
+++ b/arch/x86/include/uapi/asm/msr-index.h
@@ -297,6 +297,8 @@
#define MSR_IA32_TSC_ADJUST 0x0000003b
#define MSR_IA32_BNDCFGS 0x00000d90

+#define MSR_IA32_XSS 0x00000da0
+
#define FEATURE_CONTROL_LOCKED (1<<0)
#define FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX (1<<1)
#define FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX (1<<2)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a135239..e7c4b97 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -632,6 +632,15 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
c->x86_capability[9] = ebx;
}

+ /* Extended state features: level 0x0000000d */
+ if (c->cpuid_level >= 0x0000000d) {
+ u32 eax, ebx, ecx, edx;
+
+ cpuid_count(0x0000000d, 1, &eax, &ebx, &ecx, &edx);
+
+ c->x86_capability[10] = eax;
+ }
+
/* AMD-defined flags: level 0x80000001 */
xlvl = cpuid_eax(0x80000000);
c->extended_cpuid_level = xlvl;
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index b6f794a..4a8013d 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -38,7 +38,6 @@ void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
{ X86_FEATURE_PTS, CR_EAX, 6, 0x00000006, 0 },
{ X86_FEATURE_APERFMPERF, CR_ECX, 0, 0x00000006, 0 },
{ X86_FEATURE_EPB, CR_ECX, 3, 0x00000006, 0 },
- { X86_FEATURE_XSAVEOPT, CR_EAX, 0, 0x0000000d, 1 },
{ X86_FEATURE_HW_PSTATE, CR_EDX, 7, 0x80000007, 0 },
{ X86_FEATURE_CPB, CR_EDX, 9, 0x80000007, 0 },
{ X86_FEATURE_PROC_FEEDBACK, CR_EDX,11, 0x80000007, 0 },
--
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