diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index fb729f4c4fbc..7de63c32a8b0 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -101,6 +101,8 @@ SYM_CODE_START(entry_SYSCALL_64)
 	SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp
 	movq	PER_CPU_VAR(cpu_current_top_of_stack), %rsp
 
+SYM_INNER_LABEL(entry_SYSCALL_64_safe_stack, SYM_L_GLOBAL)
+
 	/* Construct struct pt_regs on stack */
 	pushq	$__USER_DS				/* pt_regs->ss */
 	pushq	PER_CPU_VAR(cpu_tss_rw + TSS_sp2)	/* pt_regs->sp */
@@ -446,6 +448,82 @@ _ASM_NOKPROBE(\asmsym)
 SYM_CODE_END(\asmsym)
 .endm
 
+/**
+ * idtentry_vc - Macro to generate entry stub for #VC
+ * @vector:		Vector number
+ * @asmsym:		ASM symbol for the entry point
+ * @cfunc:		C function to be called
+ *
+ * The macro emits code to set up the kernel context for #VC. The #VC handler
+ * runs on an IST stack and needs to be able to cause nested #VC exceptions.
+ *
+ * To make this work the #VC entry code tries its best to pretend it doesn't use
+ * an IST stack by switching to the task stack if coming from user-space (which
+ * includes early SYSCALL entry path) or back to the stack in the IRET frame if
+ * entered from kernel-mode.
+ *
+ * If entered from kernel-mode the return stack is validated first, and if it is
+ * not safe to use (e.g. because it points to the entry stack) the #VC handler
+ * will switch to a fall-back stack (VC2) and call a special handler function.
+ *
+ * The macro is only used for one vector, but it is planned to extend it in the
+ * future for the #HV exception.
+ */
+.macro idtentry_vc vector asmsym cfunc
+SYM_CODE_START(\asmsym)
+	UNWIND_HINT_IRET_REGS
+	ASM_CLAC
+
+	/*
+	 * If the entry is from userspace, switch stacks and treat it as
+	 * a normal entry.
+	 */
+	testb	$3, CS-ORIG_RAX(%rsp)
+	jnz	.Lfrom_usermode_switch_stack_\@
+
+	/*
+	 * paranoid_entry returns SWAPGS flag for paranoid_exit in EBX.
+	 * EBX == 0 -> SWAPGS, EBX == 1 -> no SWAPGS
+	 */
+	call	paranoid_entry
+
+	UNWIND_HINT_REGS
+
+	/*
+	 * Switch off the IST stack to make it free for nested exceptions. The
+	 * vc_switch_off_ist() function will switch back to the interrupted
+	 * stack if it is safe to do so. If not it switches to the VC fall-back
+	 * stack.
+	 */
+	movq	%rsp, %rdi		/* pt_regs pointer */
+	call	vc_switch_off_ist
+	movq	%rax, %rsp		/* Switch to new stack */
+
+	UNWIND_HINT_REGS
+
+	/* Update pt_regs */
+	movq	ORIG_RAX(%rsp), %rsi	/* get error code into 2nd argument*/
+	movq	$-1, ORIG_RAX(%rsp)	/* no syscall to restart */
+
+	movq	%rsp, %rdi		/* pt_regs pointer */
+
+	call	\cfunc
+
+	/*
+	 * No need to switch back to the IST stack. The current stack is either
+	 * identical to the stack in the IRET frame or the VC fall-back stack,
+	 * so it is definitly mapped even with PTI enabled.
+	 */
+	jmp	paranoid_exit
+
+	/* Switch to the regular task stack */
+.Lfrom_usermode_switch_stack_\@:
+	idtentry_body safe_stack_\cfunc, has_error_code=1
+
+_ASM_NOKPROBE(\asmsym)
+SYM_CODE_END(\asmsym)
+.endm
+
 /*
  * Double fault entry. Straight paranoid. No checks from which context
  * this comes because for the espfix induced #DF this would do the wrong
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 69d00e64d959..e945da5826c0 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -317,6 +317,18 @@ static __always_inline void __##func(struct pt_regs *regs)
 	DECLARE_IDTENTRY_RAW(vector, func);				\
 	__visible void noist_##func(struct pt_regs *regs)
 
+/**
+ * DECLARE_IDTENTRY_VC - Declare functions for the VC entry point
+ * @vector:	Vector number (ignored for C)
+ * @func:	Function name of the entry point
+ *
+ * Maps to DECLARE_IDTENTRY_RAW_ERRORCODE, but declares also the
+ * safe_stack C handler.
+ */
+#define DECLARE_IDTENTRY_VC(vector, func)				\
+	DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func);			\
+	__visible noinstr void safe_stack_##func(struct pt_regs *regs, unsigned long error_code)
+
 /**
  * DEFINE_IDTENTRY_IST - Emit code for IST entry points
  * @func:	Function name of the entry point
@@ -356,6 +368,35 @@ static __always_inline void __##func(struct pt_regs *regs)
 #define DEFINE_IDTENTRY_DF(func)					\
 	DEFINE_IDTENTRY_RAW_ERRORCODE(func)
 
+/**
+ * DEFINE_IDTENTRY_VC_SAFE_STACK - Emit code for VMM communication handler
+				   which runs on a safe stack.
+ * @func:	Function name of the entry point
+ *
+ * Maps to DEFINE_IDTENTRY_RAW_ERRORCODE
+ */
+#define DEFINE_IDTENTRY_VC_SAFE_STACK(func)				\
+	DEFINE_IDTENTRY_RAW_ERRORCODE(safe_stack_##func)
+
+/**
+ * DEFINE_IDTENTRY_VC_IST - Emit code for VMM communication handler
+			    which runs on the VC fall-back stack
+ * @func:	Function name of the entry point
+ *
+ * Maps to DEFINE_IDTENTRY_RAW_ERRORCODE
+ */
+#define DEFINE_IDTENTRY_VC_IST(func)				\
+	DEFINE_IDTENTRY_RAW_ERRORCODE(ist_##func)
+
+/**
+ * DEFINE_IDTENTRY_VC - Emit code for VMM communication handler
+ * @func:	Function name of the entry point
+ *
+ * Maps to DEFINE_IDTENTRY_RAW_ERRORCODE
+ */
+#define DEFINE_IDTENTRY_VC(func)					\
+	DEFINE_IDTENTRY_RAW_ERRORCODE(func)
+
 #else	/* CONFIG_X86_64 */
 
 /**
@@ -442,6 +483,9 @@ __visible noinstr void func(struct pt_regs *regs,			\
 # define DECLARE_IDTENTRY_XENCB(vector, func)				\
 	DECLARE_IDTENTRY(vector, func)
 
+# define DECLARE_IDTENTRY_VC(vector, func)				\
+	idtentry_vc vector asm_##func func
+
 #else
 # define DECLARE_IDTENTRY_MCE(vector, func)				\
 	DECLARE_IDTENTRY(vector, func)
diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h
index 6e81788a30c1..40f1f0cb73d7 100644
--- a/arch/x86/include/asm/proto.h
+++ b/arch/x86/include/asm/proto.h
@@ -10,6 +10,7 @@ void syscall_init(void);
 
 #ifdef CONFIG_X86_64
 void entry_SYSCALL_64(void);
+void entry_SYSCALL_64_safe_stack(void);
 long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2);
 #endif
 
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 6a308355ea29..1b86bb3abc56 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -15,6 +15,7 @@ asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs);
 asmlinkage __visible notrace
 struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s);
 void __init trap_init(void);
+asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *eregs);
 #endif
 
 #ifdef CONFIG_X86_F00F_BUG
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 24f6f0a19a49..4304d7af3483 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -43,6 +43,7 @@
 #include <asm/stacktrace.h>
 #include <asm/processor.h>
 #include <asm/debugreg.h>
+#include <asm/realmode.h>
 #include <asm/text-patching.h>
 #include <asm/ftrace.h>
 #include <asm/traps.h>
@@ -675,6 +676,56 @@ asmlinkage __visible noinstr struct pt_regs *sync_regs(struct pt_regs *eregs)
 	return regs;
 }
 
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *eregs)
+{
+	unsigned long sp, *stack;
+	struct stack_info info;
+	struct pt_regs *regs;
+
+	/*
+	 * In the SYSCALL entry path the RSP value comes from user-space - don't
+	 * trust it and switch to the current kernel stack
+	 */
+	if (eregs->ip >= (unsigned long)entry_SYSCALL_64 &&
+	    eregs->ip <  (unsigned long)entry_SYSCALL_64_safe_stack) {
+		sp = this_cpu_read(cpu_current_top_of_stack);
+		goto sync;
+	}
+
+	/*
+	 * From here on the the RSP value is trusted - more RSP sanity checks
+	 * need to happen above.
+	 *
+	 * Check whether entry happened from a safe stack.
+	 */
+	sp    = eregs->sp;
+	stack = (unsigned long *)sp;
+	get_stack_info_noinstr(stack, current, &info);
+
+	/*
+	 * Don't sync to entry stack or other unknown stacks - use the fall-back
+	 * stack instead.
+	 */
+	if (info.type == STACK_TYPE_UNKNOWN || info.type == STACK_TYPE_ENTRY ||
+	    info.type >= STACK_TYPE_EXCEPTION_LAST)
+		sp = __this_cpu_ist_top_va(VC2);
+
+sync:
+	/*
+	 * Found a safe stack - switch to it as if the entry didn't happen via
+	 * IST stack. The code below only copies pt_regs, the real switch happens
+	 * in assembly code.
+	 */
+	sp = ALIGN_DOWN(sp, 8) - sizeof(*regs);
+
+	regs = (struct pt_regs *)sp;
+	*regs = *eregs;
+
+	return regs;
+}
+#endif
+
 struct bad_iret_stack {
 	void *error_entry_ret;
 	struct pt_regs regs;
