linux-kernel - [RFC PATCH V2 02/11] x86/cpufeature: Add intel Sub-Page Protection to CPU features

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Date:   Fri, 30 Nov 2018 16:08:06 +0800
From:   Zhang Yi <yi.z.zhang@...ux.intel.com>
To:     pbonzini@...hat.com, mdontu@...defender.com, ncitu@...defender.com
Cc:     rkrcmar@...hat.com, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, Zhang Yi <yi.z.zhang@...ux.intel.com>
Subject: [RFC PATCH V2 02/11] x86/cpufeature: Add intel Sub-Page Protection to CPU features

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 <yi.z.zhang@...ux.intel.com>
Signed-off-by: He Chen <he.chen@...ux.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 28c4a50..e22567e 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -228,6 +228,7 @@
 #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 fc3c07f..b55156c 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -476,6 +476,7 @@ static void detect_vmx_virtcap(struct cpuinfo_x86 *c)
 #define X86_VMX_FEATURE_PROC_CTLS2_EPT		0x00000002
 #define X86_VMX_FEATURE_PROC_CTLS2_VPID		0x00000020
 #define x86_VMX_FEATURE_EPT_CAP_AD		0x00200000
+#define X86_VMX_FEATURE_PROC_CTLS2_SPP		0x00800000
 
 	u32 vmx_msr_low, vmx_msr_high, msr_ctl, msr_ctl2;
 	u32 msr_vpid_cap, msr_ept_cap;
@@ -486,6 +487,7 @@ static void detect_vmx_virtcap(struct cpuinfo_x86 *c)
 	clear_cpu_cap(c, X86_FEATURE_EPT);
 	clear_cpu_cap(c, X86_FEATURE_VPID);
 	clear_cpu_cap(c, X86_FEATURE_EPT_AD);
+	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;
@@ -509,6 +511,8 @@ static void detect_vmx_virtcap(struct cpuinfo_x86 *c)
 		}
 		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