x86: extended "flags" to show virtualization HW feature in /proc/cpuinfo

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>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 41 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 5f76bf139fda..99468dbd08da 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