Re: [PATCH] KVM: s390: generate kvm hypercall functions

[Christian Borntraeger <borntraeger@xxxxxxxxxx>]

On 13.07.21 16:57, Heiko Carstens wrote:
> Generate kvm hypercall functions with a macro instead of duplicating
> the more or less identical code seven times. This also reduces number
> of lines of code.
> However the main purpose is to get rid of as many as possible open
> coded error prone register asm constructs in s390 architecture code.
>
> For the only user of kvm_hypercall identical code is created
> before/after this patch (drivers/s390/virtio/virtio_ccw.c).
>
> Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>

Thanks applied. Will queue for 5.15.
> ---
>   arch/s390/include/asm/kvm_para.h | 229 ++++++++++---------------------
>   1 file changed, 73 insertions(+), 156 deletions(-)
>
> diff --git a/arch/s390/include/asm/kvm_para.h b/arch/s390/include/asm/kvm_para.h
> index cbc7c3a68e4d..df73a052760c 100644
> --- a/arch/s390/include/asm/kvm_para.h
> +++ b/arch/s390/include/asm/kvm_para.h
> @@ -24,162 +24,79 @@
>   #include <uapi/asm/kvm_para.h>
>   #include <asm/diag.h>
>   
> -static inline long __kvm_hypercall0(unsigned long nr)
> -{
> -	register unsigned long __nr asm("1") = nr;
> -	register long __rc asm("2");
> -
> -	asm volatile ("diag 2,4,0x500\n"
> -		      : "=d" (__rc) : "d" (__nr): "memory", "cc");
> -	return __rc;
> -}
> -
> -static inline long kvm_hypercall0(unsigned long nr)
> -{
> -	diag_stat_inc(DIAG_STAT_X500);
> -	return __kvm_hypercall0(nr);
> -}
> -
> -static inline long __kvm_hypercall1(unsigned long nr, unsigned long p1)
> -{
> -	register unsigned long __nr asm("1") = nr;
> -	register unsigned long __p1 asm("2") = p1;
> -	register long __rc asm("2");
> -
> -	asm volatile ("diag 2,4,0x500\n"
> -		      : "=d" (__rc) : "d" (__nr), "0" (__p1) : "memory", "cc");
> -	return __rc;
> -}
> -
> -static inline long kvm_hypercall1(unsigned long nr, unsigned long p1)
> -{
> -	diag_stat_inc(DIAG_STAT_X500);
> -	return __kvm_hypercall1(nr, p1);
> -}
> -
> -static inline long __kvm_hypercall2(unsigned long nr, unsigned long p1,
> -			       unsigned long p2)
> -{
> -	register unsigned long __nr asm("1") = nr;
> -	register unsigned long __p1 asm("2") = p1;
> -	register unsigned long __p2 asm("3") = p2;
> -	register long __rc asm("2");
> -
> -	asm volatile ("diag 2,4,0x500\n"
> -		      : "=d" (__rc) : "d" (__nr), "0" (__p1), "d" (__p2)
> -		      : "memory", "cc");
> -	return __rc;
> -}
> -
> -static inline long kvm_hypercall2(unsigned long nr, unsigned long p1,
> -			       unsigned long p2)
> -{
> -	diag_stat_inc(DIAG_STAT_X500);
> -	return __kvm_hypercall2(nr, p1, p2);
> -}
> -
> -static inline long __kvm_hypercall3(unsigned long nr, unsigned long p1,
> -			       unsigned long p2, unsigned long p3)
> -{
> -	register unsigned long __nr asm("1") = nr;
> -	register unsigned long __p1 asm("2") = p1;
> -	register unsigned long __p2 asm("3") = p2;
> -	register unsigned long __p3 asm("4") = p3;
> -	register long __rc asm("2");
> -
> -	asm volatile ("diag 2,4,0x500\n"
> -		      : "=d" (__rc) : "d" (__nr), "0" (__p1), "d" (__p2),
> -			"d" (__p3) : "memory", "cc");
> -	return __rc;
> -}
> -
> -static inline long kvm_hypercall3(unsigned long nr, unsigned long p1,
> -			       unsigned long p2, unsigned long p3)
> -{
> -	diag_stat_inc(DIAG_STAT_X500);
> -	return __kvm_hypercall3(nr, p1, p2, p3);
> -}
> -
> -static inline long __kvm_hypercall4(unsigned long nr, unsigned long p1,
> -			       unsigned long p2, unsigned long p3,
> -			       unsigned long p4)
> -{
> -	register unsigned long __nr asm("1") = nr;
> -	register unsigned long __p1 asm("2") = p1;
> -	register unsigned long __p2 asm("3") = p2;
> -	register unsigned long __p3 asm("4") = p3;
> -	register unsigned long __p4 asm("5") = p4;
> -	register long __rc asm("2");
> -
> -	asm volatile ("diag 2,4,0x500\n"
> -		      : "=d" (__rc) : "d" (__nr), "0" (__p1), "d" (__p2),
> -			"d" (__p3), "d" (__p4) : "memory", "cc");
> -	return __rc;
> -}
> -
> -static inline long kvm_hypercall4(unsigned long nr, unsigned long p1,
> -			       unsigned long p2, unsigned long p3,
> -			       unsigned long p4)
> -{
> -	diag_stat_inc(DIAG_STAT_X500);
> -	return __kvm_hypercall4(nr, p1, p2, p3, p4);
> -}
> -
> -static inline long __kvm_hypercall5(unsigned long nr, unsigned long p1,
> -			       unsigned long p2, unsigned long p3,
> -			       unsigned long p4, unsigned long p5)
> -{
> -	register unsigned long __nr asm("1") = nr;
> -	register unsigned long __p1 asm("2") = p1;
> -	register unsigned long __p2 asm("3") = p2;
> -	register unsigned long __p3 asm("4") = p3;
> -	register unsigned long __p4 asm("5") = p4;
> -	register unsigned long __p5 asm("6") = p5;
> -	register long __rc asm("2");
> -
> -	asm volatile ("diag 2,4,0x500\n"
> -		      : "=d" (__rc) : "d" (__nr), "0" (__p1), "d" (__p2),
> -			"d" (__p3), "d" (__p4), "d" (__p5)  : "memory", "cc");
> -	return __rc;
> -}
> -
> -static inline long kvm_hypercall5(unsigned long nr, unsigned long p1,
> -			       unsigned long p2, unsigned long p3,
> -			       unsigned long p4, unsigned long p5)
> -{
> -	diag_stat_inc(DIAG_STAT_X500);
> -	return __kvm_hypercall5(nr, p1, p2, p3, p4, p5);
> -}
> -
> -static inline long __kvm_hypercall6(unsigned long nr, unsigned long p1,
> -			       unsigned long p2, unsigned long p3,
> -			       unsigned long p4, unsigned long p5,
> -			       unsigned long p6)
> -{
> -	register unsigned long __nr asm("1") = nr;
> -	register unsigned long __p1 asm("2") = p1;
> -	register unsigned long __p2 asm("3") = p2;
> -	register unsigned long __p3 asm("4") = p3;
> -	register unsigned long __p4 asm("5") = p4;
> -	register unsigned long __p5 asm("6") = p5;
> -	register unsigned long __p6 asm("7") = p6;
> -	register long __rc asm("2");
> -
> -	asm volatile ("diag 2,4,0x500\n"
> -		      : "=d" (__rc) : "d" (__nr), "0" (__p1), "d" (__p2),
> -			"d" (__p3), "d" (__p4), "d" (__p5), "d" (__p6)
> -		      : "memory", "cc");
> -	return __rc;
> -}
> -
> -static inline long kvm_hypercall6(unsigned long nr, unsigned long p1,
> -			       unsigned long p2, unsigned long p3,
> -			       unsigned long p4, unsigned long p5,
> -			       unsigned long p6)
> -{
> -	diag_stat_inc(DIAG_STAT_X500);
> -	return __kvm_hypercall6(nr, p1, p2, p3, p4, p5, p6);
> -}
> +#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)