Re: [RFC 3/8] s390x/pci: fix pcistb length

[Cornelia Huck <cohuck@redhat.com>]

On Wed,  9 Dec 2020 15:34:21 -0500
Matthew Rosato <mjrosato@linux.ibm.com> wrote:

> In pcistb_service_call, we are grabbing 8 bits from a guest register to
> indicate the length of the store operation -- but per the architecture
> the length is actually defined by 13 bits of the guest register.
> 
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
>  hw/s390x/s390-pci-inst.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
> index 70bfd91..db86f12 100644
> --- a/hw/s390x/s390-pci-inst.c
> +++ b/hw/s390x/s390-pci-inst.c
> @@ -750,7 +750,7 @@ int pcistb_service_call(S390CPU *cpu, uint8_t r1, uint8_t r3, uint64_t gaddr,
>      int i;
>      uint32_t fh;
>      uint8_t pcias;
> -    uint8_t len;
> +    uint16_t len;
>      uint8_t buffer[128];
>  
>      if (env->psw.mask & PSW_MASK_PSTATE) {
> @@ -760,7 +760,7 @@ int pcistb_service_call(S390CPU *cpu, uint8_t r1, uint8_t r3, uint64_t gaddr,
>  
>      fh = env->regs[r1] >> 32;
>      pcias = (env->regs[r1] >> 16) & 0xf;
> -    len = env->regs[r1] & 0xff;
> +    len = env->regs[r1] & 0x1fff;
>      offset = env->regs[r3];
>  
>      if (!(fh & FH_MASK_ENABLE)) {

Is that a general problem that we just did not notice before?

If yes, this probably deserves a Fixes: tag and can be queued
independently of the rest of the series.