Quoting Janosch Frank (2023-04-21 13:36:41)
> PV related validities are in the 0x20** range but the last byte might
> be implementation specific, so everytime we check for a UV validity we
> need to mask the last byte.
>
> Let's add a function that checks for a UV validity and returns a
> boolean.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
> Reviewed-by: Nico Boehr <nrb@xxxxxxxxxxxxx>
> ---
> lib/s390x/uv.h | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/lib/s390x/uv.h b/lib/s390x/uv.h
> index 5fe29bda..78b979b7 100644
> --- a/lib/s390x/uv.h
> +++ b/lib/s390x/uv.h
> @@ -35,4 +35,11 @@ static inline void uv_setup_asces(void)
> lctlg(13, asce);
> }
>
> +static inline bool uv_validity_check(struct vm *vm)
> +{
> + uint16_t vir = sie_get_validity(vm);
> +
> + return vm->sblk->icptcode == ICPT_VALIDITY && (vir & 0xff00) == 0x2000;
> +}
> +
I noticed a small issue with this. If no intercept occurs, we sie_get_validity()
will be called which will assert() when there's none.
Please consider the following fixup (broken whitespace ahead):
static inline bool uv_validity_check(struct vm *vm)
{
- uint16_t vir = sie_get_validity(vm);
+ uint16_t vir;
- return vm->sblk->icptcode == ICPT_VALIDITY && (vir & 0xff00) == 0x2000;
+ /* must not use sie_get_validity() when there's no validity */
+ if (vm->sblk->icptcode != ICPT_VALIDITY)
+ return false;
+ vir = sie_get_validity(vm);
+
+ return (vir & 0xff00) == 0x2000;
}
