1 files changed, 57 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
new file mode 100644
index 000000000000..bcef2c7e9bc4
--- /dev/null
+++ b/arch/x86/kvm/vmx/vmenter.S
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/linkage.h>
+#include <asm/asm.h>
+
+	.text
+
+/**
+ * vmx_vmenter - VM-Enter the current loaded VMCS
+ *
+ * %RFLAGS.ZF:	!VMCS.LAUNCHED, i.e. controls VMLAUNCH vs. VMRESUME
+ *
+ * Returns:
+ *	%RFLAGS.CF is set on VM-Fail Invalid
+ *	%RFLAGS.ZF is set on VM-Fail Valid
+ *	%RFLAGS.{CF,ZF} are cleared on VM-Success, i.e. VM-Exit
+ *
+ * Note that VMRESUME/VMLAUNCH fall-through and return directly if
+ * they VM-Fail, whereas a successful VM-Enter + VM-Exit will jump
+ * to vmx_vmexit.
+ */
+ENTRY(vmx_vmenter)
+	/* EFLAGS.ZF is set if VMCS.LAUNCHED == 0 */
+	je 2f
+
+1:	vmresume
+	ret
+
+2:	vmlaunch
+	ret
+
+3:	cmpb $0, kvm_rebooting
+	jne 4f
+	call kvm_spurious_fault
+4:	ret
+
+	.pushsection .fixup, "ax"
+5:	jmp 3b
+	.popsection
+
+	_ASM_EXTABLE(1b, 5b)
+	_ASM_EXTABLE(2b, 5b)
+
+ENDPROC(vmx_vmenter)
+
+/**
+ * vmx_vmexit - Handle a VMX VM-Exit
+ *
+ * Returns:
+ *	%RFLAGS.{CF,ZF} are cleared on VM-Success, i.e. VM-Exit
+ *
+ * This is vmx_vmenter's partner in crime.  On a VM-Exit, control will jump
+ * here after hardware loads the host's state, i.e. this is the destination
+ * referred to by VMCS.HOST_RIP.
+ */
+ENTRY(vmx_vmexit)
+	ret
+ENDPROC(vmx_vmexit)