/* SPDX-License-Identifier: GPL-2.0 */
/*
 * definition for paravirtual devices on s390
 *
 * Copyright IBM Corp. 2008
 *
 *    Author(s): Christian Borntraeger <[email protected]>
 */
/*
 * Hypercalls for KVM on s390. The calling convention is similar to the
 * s390 ABI, so we use R2-R6 for parameters 1-5. In addition we use R1
 * as hypercall number and R7 as parameter 6. The return value is
 * written to R2. We use the diagnose instruction as hypercall. To avoid
 * conflicts with existing diagnoses for LPAR and z/VM, we do not use
 * the instruction encoded number, but specify the number in R1 and
 * use 0x500 as KVM hypercall
 *
 * Copyright IBM Corp. 2007,2008
 * Author(s): Christian Borntraeger <[email protected]>
 */
#ifndef __S390_KVM_PARA_H
#define __S390_KVM_PARA_H

#include <uapi/asm/kvm_para.h>
#include <asm/diag.h>

#define HYPERCALL_FMT_0
#define HYPERCALL_FMT_1 , "0" (r2)
#define HYPERCALL_FMT_2 , "d" (r3) HYPERCALL_FMT_1
#define HYPERCALL_FMT_3 , "d" (r4) HYPERCALL_FMT_2
#define HYPERCALL_FMT_4 , "d" (r5) HYPERCALL_FMT_3
#define HYPERCALL_FMT_5 , "d" (r6) HYPERCALL_FMT_4
#define HYPERCALL_FMT_6 , "d" (r7) HYPERCALL_FMT_5

#define HYPERCALL_PARM_0
#define HYPERCALL_PARM_1 , unsigned long arg1
#define HYPERCALL_PARM_2 HYPERCALL_PARM_1, unsigned long arg2
#define HYPERCALL_PARM_3 HYPERCALL_PARM_2, unsigned long arg3
#define HYPERCALL_PARM_4 HYPERCALL_PARM_3, unsigned long arg4
#define HYPERCALL_PARM_5 HYPERCALL_PARM_4, unsigned long arg5
#define HYPERCALL_PARM_6 HYPERCALL_PARM_5, unsigned long arg6

#define HYPERCALL_REGS_0
#define HYPERCALL_REGS_1						\
	register unsigned long r2 asm("2") = arg1
#define HYPERCALL_REGS_2						\
	HYPERCALL_REGS_1;						\
	register unsigned long r3 asm("3") = arg2
#define HYPERCALL_REGS_3						\
	HYPERCALL_REGS_2;						\
	register unsigned long r4 asm("4") = arg3
#define HYPERCALL_REGS_4						\
	HYPERCALL_REGS_3;						\
	register unsigned long r5 asm("5") = arg4
#define HYPERCALL_REGS_5						\
	HYPERCALL_REGS_4;						\
	register unsigned long r6 asm("6") = arg5
#define HYPERCALL_REGS_6						\
	HYPERCALL_REGS_5;						\
	register unsigned long r7 asm("7") = arg6

#define HYPERCALL_ARGS_0
#define HYPERCALL_ARGS_1 , arg1
#define HYPERCALL_ARGS_2 HYPERCALL_ARGS_1, arg2
#define HYPERCALL_ARGS_3 HYPERCALL_ARGS_2, arg3
#define HYPERCALL_ARGS_4 HYPERCALL_ARGS_3, arg4
#define HYPERCALL_ARGS_5 HYPERCALL_ARGS_4, arg5
#define HYPERCALL_ARGS_6 HYPERCALL_ARGS_5, arg6

#define GENERATE_KVM_HYPERCALL_FUNC(args)				\
static inline								\
long __kvm_hypercall##args(unsigned long nr HYPERCALL_PARM_##args)	\
{									\
	register unsigned long __nr asm("1") = nr;			\
	register long __rc asm("2");					\
	HYPERCALL_REGS_##args;						\
									\
	asm volatile (							\
		"	diag	2,4,0x500\n"				\
		: "=d" (__rc)						\
		: "d" (__nr) HYPERCALL_FMT_##args			\
		: "memory", "cc");					\
	return __rc;							\
}									\
									\
static inline								\
long kvm_hypercall##args(unsigned long nr HYPERCALL_PARM_##args)	\
{									\
	diag_stat_inc(DIAG_STAT_X500);					\
	return __kvm_hypercall##args(nr HYPERCALL_ARGS_##args);		\
}

GENERATE_KVM_HYPERCALL_FUNC(0)
GENERATE_KVM_HYPERCALL_FUNC(1)
GENERATE_KVM_HYPERCALL_FUNC(2)
GENERATE_KVM_HYPERCALL_FUNC(3)
GENERATE_KVM_HYPERCALL_FUNC(4)
GENERATE_KVM_HYPERCALL_FUNC(5)
GENERATE_KVM_HYPERCALL_FUNC(6)

/* kvm on s390 is always paravirtualization enabled */
static inline int kvm_para_available(void)
{
	return 1;
}

/* No feature bits are currently assigned for kvm on s390 */
static inline unsigned int kvm_arch_para_features(void)
{
	return 0;
}

static inline unsigned int kvm_arch_para_hints(void)
{
	return 0;
}

static inline bool kvm_check_and_clear_guest_paused(void)
{
	return false;
}

#endif /* __S390_KVM_PARA_H */