[PATCH RFC 03/10] KVM: VMX: Added VMX SPP feature flags and VM-Execution Controls.

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

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

Add new secondary processor-based VM-execution control bit which
defined as "sub-page write permission", same as VMX Procbased MSR,
bit 23 is the enable bit of SPP.

Also we introduced a enable_ept_spp parameter to control the
SPP is ON/OFF, Set the default is OFF as we are on the way of
enabling.

Now SPP is active when the "Sub-page Write Protection"
in Secondary VM-Execution Control is set and enable the kernel
parameter by "spp=on".

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/vmx.h |  1 +
 arch/x86/kvm/vmx.c         | 16 ++++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index caec841..633dff5 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -77,6 +77,7 @@
 #define SECONDARY_EXEC_RDSEED			0x00010000
 #define SECONDARY_EXEC_ENABLE_PML               0x00020000
 #define SECONDARY_EXEC_XSAVES			0x00100000
+#define SECONDARY_EXEC_ENABLE_SPP		0x00800000
 #define SECONDARY_EXEC_TSC_SCALING              0x02000000
 
 #define PIN_BASED_EXT_INTR_MASK                 0x00000001
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8ed90f7c..1a2ca87 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -82,6 +82,9 @@ module_param_named(unrestricted_guest,
 static bool __read_mostly enable_ept_ad_bits = 1;
 module_param_named(eptad, enable_ept_ad_bits, bool, S_IRUGO);
 
+static bool __read_mostly enable_ept_spp;
+module_param_named(spp, enable_ept_spp, bool, S_IRUGO);
+
 static bool __read_mostly emulate_invalid_guest_state = true;
 module_param(emulate_invalid_guest_state, bool, S_IRUGO);
 
@@ -1307,6 +1310,11 @@ static inline bool cpu_has_vmx_pml(void)
 	return vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_ENABLE_PML;
 }
 
+static inline bool cpu_has_vmx_ept_spp(void)
+{
+	return vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_ENABLE_SPP;
+}
+
 static inline bool cpu_has_vmx_tsc_scaling(void)
 {
 	return vmcs_config.cpu_based_2nd_exec_ctrl &
@@ -3660,6 +3668,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 			SECONDARY_EXEC_RDSEED |
 			SECONDARY_EXEC_RDRAND |
 			SECONDARY_EXEC_ENABLE_PML |
+			SECONDARY_EXEC_ENABLE_SPP |
 			SECONDARY_EXEC_TSC_SCALING |
 			SECONDARY_EXEC_ENABLE_VMFUNC;
 		if (adjust_vmx_controls(min2, opt2,
@@ -5323,6 +5332,9 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
 	if (!enable_pml)
 		exec_control &= ~SECONDARY_EXEC_ENABLE_PML;
 
+	if (!enable_ept_spp)
+		exec_control &= ~SECONDARY_EXEC_ENABLE_SPP;
+
 	if (vmx_xsaves_supported()) {
 		/* Exposing XSAVES only when XSAVE is exposed */
 		bool xsaves_enabled =
@@ -6753,11 +6765,15 @@ static __init int hardware_setup(void)
 		enable_ept = 0;
 		enable_unrestricted_guest = 0;
 		enable_ept_ad_bits = 0;
+		enable_ept_spp = 0;
 	}
 
 	if (!cpu_has_vmx_ept_ad_bits() || !enable_ept)
 		enable_ept_ad_bits = 0;
 
+	if (!cpu_has_vmx_ept_spp())
+		enable_ept_spp = 0;
+
 	if (!cpu_has_vmx_unrestricted_guest())
 		enable_unrestricted_guest = 0;
 
-- 
2.7.4