Re: [PATCH v9] fixup! Fix subcode/pbt

[Cornelia Huck <cohuck@redhat.com>]

On Fri, 13 Mar 2020 05:52:32 -0400
Janosch Frank <frankja@linux.ibm.com> wrote:

> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
>  hw/s390x/ipl.h      | 11 +++++++----
>  target/s390x/diag.c |  2 +-
>  2 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/s390x/ipl.h b/hw/s390x/ipl.h
> index 95e3183c9cccf8b6..f799f7cfcf4763b1 100644
> --- a/hw/s390x/ipl.h
> +++ b/hw/s390x/ipl.h
> @@ -261,15 +261,18 @@ static inline bool ipl_valid_pv_header(IplParameterBlock *iplb)
>          return true;
>  }
>  
> -static inline bool iplb_valid(IplParameterBlock *iplb)
> +static inline bool iplb_valid(IplParameterBlock *iplb, uint64_t subcode)
>  {
>      switch (iplb->pbt) {
>      case S390_IPL_TYPE_FCP:
> -        return be32_to_cpu(iplb->len) >= S390_IPLB_MIN_FCP_LEN;
> +        return (subcode == DIAG308_SET &&
> +                be32_to_cpu(iplb->len) >= S390_IPLB_MIN_FCP_LEN);
>      case S390_IPL_TYPE_CCW:
> -        return be32_to_cpu(iplb->len) >= S390_IPLB_MIN_CCW_LEN;
> +        return (subcode == DIAG308_SET &&
> +                be32_to_cpu(iplb->len) >= S390_IPLB_MIN_CCW_LEN);
>      case S390_IPL_TYPE_PV:
> -        if (be32_to_cpu(iplb->len) < S390_IPLB_MIN_PV_LEN) {
> +        if (subcode != DIAG308_PV_SET ||
> +            be32_to_cpu(iplb->len) < S390_IPLB_MIN_PV_LEN) {
>              return false;

I'm not sure I like passing the subcode here...

>          }
>          if (!ipl_valid_pv_header(iplb)) {
> diff --git a/target/s390x/diag.c b/target/s390x/diag.c
> index b1ca81633b83bbdc..d4f33db5c23c818d 100644
> --- a/target/s390x/diag.c
> +++ b/target/s390x/diag.c
> @@ -118,7 +118,7 @@ void handle_diag_308(CPUS390XState *env, uint64_t r1, uint64_t r3, uintptr_t ra)
>  
>          cpu_physical_memory_read(addr, iplb, be32_to_cpu(iplb->len));
>  
> -        if (!iplb_valid(iplb)) {
> +        if (!iplb_valid(iplb, subcode)) {
>              env->regs[r1 + 1] = DIAG_308_RC_INVALID;
>              goto out;
>          }

...because you're basically checking whether you either have a valid
normal iplb, or a valid pv iplb, with the two being mutually exclusive,
IIUC. So what about introducing iplb_valid_pv and calling that for the
pv case? Would be a bit nicer to read, I think, and also matches what
you do for the STORE case.