1 files changed, 142 insertions, 0 deletions
diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
new file mode 100644
index 000000000..331474296
--- /dev/null
+++ b/arch/x86/include/asm/virtext.h
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* CPU virtualization extensions handling
+ *
+ * This should carry the code for handling CPU virtualization extensions
+ * that needs to live in the kernel core.
+ *
+ * Author: Eduardo Habkost <ehabkost@redhat.com>
+ *
+ * Copyright (C) 2008, Red Hat Inc.
+ *
+ * Contains code from KVM, Copyright (C) 2006 Qumranet, Inc.
+ */
+#ifndef _ASM_X86_VIRTEX_H
+#define _ASM_X86_VIRTEX_H
+
+#include <asm/processor.h>
+
+#include <asm/vmx.h>
+#include <asm/svm.h>
+#include <asm/tlbflush.h>
+
+/*
+ * VMX functions:
+ */
+
+static inline int cpu_has_vmx(void)
+{
+	unsigned long ecx = cpuid_ecx(1);
+	return test_bit(5, &ecx); /* CPUID.1:ECX.VMX[bit 5] -> VT */
+}
+
+
+/**
+ * cpu_vmxoff() - Disable VMX on the current CPU
+ *
+ * Disable VMX and clear CR4.VMXE (even if VMXOFF faults)
+ *
+ * Note, VMXOFF causes a #UD if the CPU is !post-VMXON, but it's impossible to
+ * atomically track post-VMXON state, e.g. this may be called in NMI context.
+ * Eat all faults as all other faults on VMXOFF faults are mode related, i.e.
+ * faults are guaranteed to be due to the !post-VMXON check unless the CPU is
+ * magically in RM, VM86, compat mode, or at CPL>0.
+ */
+static inline void cpu_vmxoff(void)
+{
+	asm_volatile_goto("1: vmxoff\n\t"
+			  _ASM_EXTABLE(1b, %l[fault]) :::: fault);
+fault:
+	cr4_clear_bits(X86_CR4_VMXE);
+}
+
+static inline int cpu_vmx_enabled(void)
+{
+	return __read_cr4() & X86_CR4_VMXE;
+}
+
+/** Disable VMX if it is enabled on the current CPU
+ *
+ * You shouldn't call this if cpu_has_vmx() returns 0.
+ */
+static inline void __cpu_emergency_vmxoff(void)
+{
+	if (cpu_vmx_enabled())
+		cpu_vmxoff();
+}
+
+/** Disable VMX if it is supported and enabled on the current CPU
+ */
+static inline void cpu_emergency_vmxoff(void)
+{
+	if (cpu_has_vmx())
+		__cpu_emergency_vmxoff();
+}
+
+
+
+
+/*
+ * SVM functions:
+ */
+
+/** Check if the CPU has SVM support
+ *
+ * You can use the 'msg' arg to get a message describing the problem,
+ * if the function returns zero. Simply pass NULL if you are not interested
+ * on the messages; gcc should take care of not generating code for
+ * the messages on this case.
+ */
+static inline int cpu_has_svm(const char **msg)
+{
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
+	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON) {
+		if (msg)
+			*msg = "not amd or hygon";
+		return 0;
+	}
+
+	if (!boot_cpu_has(X86_FEATURE_SVM)) {
+		if (msg)
+			*msg = "svm not available";
+		return 0;
+	}
+	return 1;
+}
+
+
+/** Disable SVM on the current CPU
+ *
+ * You should call this only if cpu_has_svm() returned true.
+ */
+static inline void cpu_svm_disable(void)
+{
+	uint64_t efer;
+
+	wrmsrl(MSR_VM_HSAVE_PA, 0);
+	rdmsrl(MSR_EFER, efer);
+	if (efer & EFER_SVME) {
+		/*
+		 * Force GIF=1 prior to disabling SVM to ensure INIT and NMI
+		 * aren't blocked, e.g. if a fatal error occurred between CLGI
+		 * and STGI.  Note, STGI may #UD if SVM is disabled from NMI
+		 * context between reading EFER and executing STGI.  In that
+		 * case, GIF must already be set, otherwise the NMI would have
+		 * been blocked, so just eat the fault.
+		 */
+		asm_volatile_goto("1: stgi\n\t"
+				  _ASM_EXTABLE(1b, %l[fault])
+				  ::: "memory" : fault);
+fault:
+		wrmsrl(MSR_EFER, efer & ~EFER_SVME);
+	}
+}
+
+/** Makes sure SVM is disabled, if it is supported on the CPU
+ */
+static inline void cpu_emergency_svm_disable(void)
+{
+	if (cpu_has_svm(NULL))
+		cpu_svm_disable();
+}
+
+#endif /* _ASM_X86_VIRTEX_H */