[PATCH RFC 02/10] x86/cpufeature: Add intel Sub-Page Protection to CPU features

[Zhang Yi <yi.z.zhang@linux.intel.com>]

From: Zhang Yi Z <yi.z.zhang@linux.intel.com>

Adds reporting SPP capability from VMX Procbased MSR, according to
the definition of hardware spec, bit 32 is the control of the SPP
capability.

Defined X86_FEATURE_SPP under intel X86 VT-x CPU features.

Defined the X86_VMX_FEATURE_PROC_CTLS2_SPP in intel VMX MSR indicated
features, And enable SPP capability by this MSR.

Signed-off-by: Zhang Yi Z <yi.z.zhang@linux.intel.com>
Signed-off-by: He Chen <he.chen@linux.intel.com>
---
 arch/x86/include/asm/cpufeatures.h | 1 +
 arch/x86/kernel/cpu/intel.c        | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 2519c6c..36cd3b9 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -211,6 +211,7 @@
 #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 */
+#define X86_FEATURE_SPP         ( 8*32+ 5) /* Intel EPT-based Sub-Page Write Protection */
 
 #define X86_FEATURE_VMMCALL     ( 8*32+15) /* Prefer vmmcall to vmcall */
 #define X86_FEATURE_XENPV       ( 8*32+16) /* "" Xen paravirtual guest */
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index dfa90a3..242978b 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -425,6 +425,7 @@ static void detect_vmx_virtcap(struct cpuinfo_x86 *c)
 #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
+#define X86_VMX_FEATURE_PROC_CTLS2_SPP		0x00800000
 
 	u32 vmx_msr_low, vmx_msr_high, msr_ctl, msr_ctl2;
 
@@ -433,6 +434,7 @@ static void detect_vmx_virtcap(struct cpuinfo_x86 *c)
 	clear_cpu_cap(c, X86_FEATURE_FLEXPRIORITY);
 	clear_cpu_cap(c, X86_FEATURE_EPT);
 	clear_cpu_cap(c, X86_FEATURE_VPID);
+	clear_cpu_cap(c, X86_FEATURE_SPP);
 
 	rdmsr(MSR_IA32_VMX_PROCBASED_CTLS, vmx_msr_low, vmx_msr_high);
 	msr_ctl = vmx_msr_high | vmx_msr_low;
@@ -451,6 +453,8 @@ static void detect_vmx_virtcap(struct cpuinfo_x86 *c)
 			set_cpu_cap(c, X86_FEATURE_EPT);
 		if (msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_VPID)
 			set_cpu_cap(c, X86_FEATURE_VPID);
+		if (msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_SPP)
+			set_cpu_cap(c, X86_FEATURE_SPP);
 	}
 }
 
-- 
2.7.4