1 files changed, 70 insertions, 3 deletions

diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index 0268185bef94..03851240c3e3 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/tboot.h>
 
+#include <asm/cpu.h>
 #include <asm/cpufeature.h>
 #include <asm/msr-index.h>
 #include <asm/processor.h>
@@ -14,6 +15,8 @@ enum vmx_feature_leafs {
 	MISC_FEATURES = 0,
 	PRIMARY_CTLS,
 	SECONDARY_CTLS,
+	TERTIARY_CTLS_LOW,
+	TERTIARY_CTLS_HIGH,
 	NR_VMX_FEATURE_WORDS,
 };
 
@@ -21,7 +24,7 @@ enum vmx_feature_leafs {
 
 static void init_vmx_capabilities(struct cpuinfo_x86 *c)
 {
-	u32 supported, funcs, ept, vpid, ign;
+	u32 supported, funcs, ept, vpid, ign, low, high;
 
 	BUILD_BUG_ON(NVMXINTS != NR_VMX_FEATURE_WORDS);
 
@@ -41,6 +44,11 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
 	rdmsr_safe(MSR_IA32_VMX_PROCBASED_CTLS2, &ign, &supported);
 	c->vmx_capability[SECONDARY_CTLS] = supported;
 
+	/* All 64 bits of tertiary controls MSR are allowed-1 settings. */
+	rdmsr_safe(MSR_IA32_VMX_PROCBASED_CTLS3, &low, &high);
+	c->vmx_capability[TERTIARY_CTLS_LOW] = low;
+	c->vmx_capability[TERTIARY_CTLS_HIGH] = high;
+
 	rdmsr(MSR_IA32_VMX_PINBASED_CTLS, ign, supported);
 	rdmsr_safe(MSR_IA32_VMX_VMFUNC, &ign, &funcs);
 
@@ -92,16 +100,42 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
 }
 #endif /* CONFIG_X86_VMX_FEATURE_NAMES */
 
+static int __init nosgx(char *str)
+{
+	setup_clear_cpu_cap(X86_FEATURE_SGX);
+
+	return 0;
+}
+
+early_param("nosgx", nosgx);
+
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 {
+	bool enable_sgx_kvm = false, enable_sgx_driver = false;
 	bool tboot = tboot_enabled();
+	bool enable_vmx;
 	u64 msr;
 
 	if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
 		clear_cpu_cap(c, X86_FEATURE_VMX);
+		clear_cpu_cap(c, X86_FEATURE_SGX);
 		return;
 	}
 
+	enable_vmx = cpu_has(c, X86_FEATURE_VMX) &&
+		     IS_ENABLED(CONFIG_KVM_INTEL);
+
+	if (cpu_has(c, X86_FEATURE_SGX) && IS_ENABLED(CONFIG_X86_SGX)) {
+		/*
+		 * Separate out SGX driver enabling from KVM.  This allows KVM
+		 * guests to use SGX even if the kernel SGX driver refuses to
+		 * use it.  This happens if flexible Launch Control is not
+		 * available.
+		 */
+		enable_sgx_driver = cpu_has(c, X86_FEATURE_SGX_LC);
+		enable_sgx_kvm = enable_vmx && IS_ENABLED(CONFIG_X86_SGX_KVM);
+	}
+
 	if (msr & FEAT_CTL_LOCKED)
 		goto update_caps;
 
@@ -116,20 +150,26 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 	 * i.e. KVM is enabled, to avoid unnecessarily adding an attack vector
 	 * for the kernel, e.g. using VMX to hide malicious code.
 	 */
-	if (cpu_has(c, X86_FEATURE_VMX) && IS_ENABLED(CONFIG_KVM_INTEL)) {
+	if (enable_vmx) {
 		msr |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
 
 		if (tboot)
 			msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
 	}
 
+	if (enable_sgx_kvm || enable_sgx_driver) {
+		msr |= FEAT_CTL_SGX_ENABLED;
+		if (enable_sgx_driver)
+			msr |= FEAT_CTL_SGX_LC_ENABLED;
+	}
+
 	wrmsrl(MSR_IA32_FEAT_CTL, msr);
 
 update_caps:
 	set_cpu_cap(c, X86_FEATURE_MSR_IA32_FEAT_CTL);
 
 	if (!cpu_has(c, X86_FEATURE_VMX))
-		return;
+		goto update_sgx;
 
 	if ( (tboot && !(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)) ||
 	    (!tboot && !(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX))) {
@@ -142,4 +182,31 @@ update_caps:
 		init_vmx_capabilities(c);
 #endif
 	}
+
+update_sgx:
+	if (!(msr & FEAT_CTL_SGX_ENABLED)) {
+		if (enable_sgx_kvm || enable_sgx_driver)
+			pr_err_once("SGX disabled by BIOS.\n");
+		clear_cpu_cap(c, X86_FEATURE_SGX);
+		return;
+	}
+
+	/*
+	 * VMX feature bit may be cleared due to being disabled in BIOS,
+	 * in which case SGX virtualization cannot be supported either.
+	 */
+	if (!cpu_has(c, X86_FEATURE_VMX) && enable_sgx_kvm) {
+		pr_err_once("SGX virtualization disabled due to lack of VMX.\n");
+		enable_sgx_kvm = 0;
+	}
+
+	if (!(msr & FEAT_CTL_SGX_LC_ENABLED) && enable_sgx_driver) {
+		if (!enable_sgx_kvm) {
+			pr_err_once("SGX Launch Control is locked. Disable SGX.\n");
+			clear_cpu_cap(c, X86_FEATURE_SGX);
+		} else {
+			pr_err_once("SGX Launch Control is locked. Support SGX virtualization only.\n");
+			clear_cpu_cap(c, X86_FEATURE_SGX_LC);
+		}
+	}
 }