Re: [kvm-unit-tests PATCH v3 4/9] lib: s390x: uv: Add UVC_ERR_DEBUG switch

[Janosch Frank <frankja@linux.ibm.com>]

On 10/7/21 10:50, Janosch Frank wrote:
> Every time something goes wrong in a way we don't expect, we need to
> add debug prints to some UVC to get the unexpected return code.
> 
> Let's just put the printing behind a macro so we can enable it if
> needed via a simple switch.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>   lib/s390x/asm/uv.h | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/lib/s390x/asm/uv.h b/lib/s390x/asm/uv.h
> index 2f099553..16db086d 100644
> --- a/lib/s390x/asm/uv.h
> +++ b/lib/s390x/asm/uv.h
> @@ -12,6 +12,11 @@
>   #ifndef _ASMS390X_UV_H_
>   #define _ASMS390X_UV_H_
>   
> +/* Enables printing of command code and return codes for failed UVCs */
> +#ifndef UVC_ERR_DEBUG
> +#define UVC_ERR_DEBUG	0
> +#endif
> +
>   #define UVC_RC_EXECUTED		0x0001
>   #define UVC_RC_INV_CMD		0x0002
>   #define UVC_RC_INV_STATE	0x0003
> @@ -194,6 +199,13 @@ static inline int uv_call_once(unsigned long r1, unsigned long r2)
>   		: [cc] "=d" (cc)
>   		: [r1] "a" (r1), [r2] "a" (r2)
>   		: "memory", "cc");
> +
> +	if (UVC_ERR_DEBUG && cc)

That needs to check cc == 1...

> +		printf("UV call error: call %x rc %x rrc %x\n",
> +		       ((struct uv_cb_header *)r2)->cmd,
> +		       ((struct uv_cb_header *)r2)->rc,
> +		       ((struct uv_cb_header *)r2)->rrc);
> +
>   	return cc;
>   }
>   
>