[PATCH 2/2] x86: Extended "flags" to show virtualization HW feature in /proc/cpuinfo

Sheng Yang
2008-09-10T10:50:27Z

The hardware virtualization technology evolves very fast. But currently
it's hard to tell if your CPU support a certain kind of HW technology
without digging into the source code.

The patch add a new catagory in "flags" under /proc/cpuinfo. Now "flags"
can indicate the (important) HW virtulization features the CPU supported
as well.

Current implementation just cover Intel VMX side.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
---
arch/x86/kernel/cpu/intel.c | 41 +++++++++++++++++++++++++++++++++++++++++
include/asm-x86/cpufeature.h | 9 ++++++++-
2 files changed, 49 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 5f76bf1..99468db 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -196,6 +196,44 @@ static int __cpuinit intel_num_cpu_cores(struct cpuinfo_x86 *c)
return 1;
}

+static void __cpuinit detect_vmx_virtcap(struct cpuinfo_x86 *c)
+{
+ /* Intel VMX MSR indicated features */
+#define X86_VMX_FEATURE_PROC_CTLS_TPR_SHADOW 0x00200000
+#define X86_VMX_FEATURE_PROC_CTLS_VNMI 0x00400000
+#define X86_VMX_FEATURE_PROC_CTLS_2ND_CTLS 0x80000000
+#define X86_VMX_FEATURE_PROC_CTLS2_VIRT_APIC 0x00000001
+#define X86_VMX_FEATURE_PROC_CTLS2_EPT 0x00000002
+#define X86_VMX_FEATURE_PROC_CTLS2_VPID 0x00000020
+
+ u32 vmx_msr_low, vmx_msr_high, msr_ctl, msr_ctl2;
+
+ clear_cpu_cap(c, X86_FEATURE_TPR_SHADOW);
+ clear_cpu_cap(c, X86_FEATURE_VNMI);
+ clear_cpu_cap(c, X86_FEATURE_FLEXPRIORITY);
+ clear_cpu_cap(c, X86_FEATURE_EPT);
+ clear_cpu_cap(c, X86_FEATURE_VPID);
+
+ rdmsr(MSR_IA32_VMX_PROCBASED_CTLS, vmx_msr_low, vmx_msr_high);
+ msr_ctl = vmx_msr_high | vmx_msr_low;
+ if (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_TPR_SHADOW)
+ set_cpu_cap(c, X86_FEATURE_TPR_SHADOW);
+ if (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_VNMI)
+ set_cpu_cap(c, X86_FEATURE_VNMI);
+ if (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_2ND_CTLS) {
+ rdmsr(MSR_IA32_VMX_PROCBASED_CTLS2,
+ vmx_msr_low, vmx_msr_high);
+ msr_ctl2 = vmx_msr_high | vmx_msr_low;
+ if ((msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_VIRT_APIC) &&
+ (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_TPR_SHADOW))
+ set_cpu_cap(c, X86_FEATURE_FLEXPRIORITY);
+ if (msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_EPT)
+ set_cpu_cap(c, X86_FEATURE_EPT);
+ if (msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_VPID)
+ set_cpu_cap(c, X86_FEATURE_VPID);
+ }
+}
+
static void __cpuinit init_intel(struct cpuinfo_x86 *c)
{
unsigned int l2 = 0;
@@ -289,6 +327,9 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)

/* Work around errata */
srat_detect_node();
+
+ if (cpu_has(c, X86_FEATURE_VMX))
+ detect_vmx_virtcap(c);
}

#ifdef CONFIG_X86_32
diff --git a/include/asm-x86/cpufeature.h b/include/asm-x86/cpufeature.h
index 7ac4d93..8d45690 100644
--- a/include/asm-x86/cpufeature.h
+++ b/include/asm-x86/cpufeature.h
@@ -6,7 +6,7 @@

#include <asm/required-features.h>

-#define NCAPINTS 8 /* N 32-bit words worth of info */
+#define NCAPINTS 9 /* N 32-bit words worth of info */

/*
* Note: If the comment begins with a quoted string, that string is used
@@ -150,6 +150,13 @@
*/
#define X86_FEATURE_IDA (7*32+ 0) /* Intel Dynamic Acceleration */

+/* Virtualization flags: Linux defined */
+#define X86_FEATURE_TPR_SHADOW (8*32+ 0) /* Intel TPR Shadow */
+#define X86_FEATURE_VNMI (8*32+ 1) /* Intel Virtual NMI */
+#define X86_FEATURE_FLEXPRIORITY (8*32+ 2) /* Intel FlexPriority */
+#define X86_FEATURE_EPT (8*32+ 3) /* Intel Extended Page Table */
+#define X86_FEATURE_VPID (8*32+ 4) /* Intel Virtual Processor ID */
+
#if defined(__KERNEL__) && !defined(__ASSEMBLY__)

#include <linux/bitops.h>
--
1.5.4.5