| Message ID | 20200910093655.255774-6-walling@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | s390: Extended-Length SCCB & DIAGNOSE 0x318 | expand |
On 10/09/2020 11.36, Collin Walling wrote: > The start of the CPU entry region in the Read SCP Info response data is > denoted by the offset_cpu field. As such, QEMU needs to begin creating > entries at this address. > > This is in preparation for when Read SCP Info inevitably introduces new > bytes that push the start of the CPUEntry field further away. > > Read CPU Info is unlikely to ever change, so let's not bother > accounting for the offset there. > > Signed-off-by: Collin Walling <walling@linux.ibm.com> > --- > hw/s390x/sclp.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) Reviewed-by: Thomas Huth <thuth@redhat.com>
On Thu, 10 Sep 2020 05:36:52 -0400 Collin Walling <walling@linux.ibm.com> wrote: > The start of the CPU entry region in the Read SCP Info response data is > denoted by the offset_cpu field. As such, QEMU needs to begin creating > entries at this address. > > This is in preparation for when Read SCP Info inevitably introduces new > bytes that push the start of the CPUEntry field further away. > > Read CPU Info is unlikely to ever change, so let's not bother > accounting for the offset there. > > Signed-off-by: Collin Walling <walling@linux.ibm.com> > --- > hw/s390x/sclp.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) Reviewed-by: Cornelia Huck <cohuck@redhat.com>
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c index 12829bdd05..803fdd5ed4 100644 --- a/hw/s390x/sclp.c +++ b/hw/s390x/sclp.c @@ -89,6 +89,8 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb) int rnsize, rnmax; IplParameterBlock *ipib = s390_ipl_get_iplb(); int required_len = SCCB_REQ_LEN(ReadInfo, machine->possible_cpus->len); + int offset_cpu = offsetof(ReadInfo, entries); + CPUEntry *entries_start = (void *)sccb + offset_cpu; if (be16_to_cpu(sccb->h.length) < required_len) { sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); @@ -96,9 +98,9 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb) } /* CPU information */ - prepare_cpu_entries(machine, read_info->entries, &cpu_count); + prepare_cpu_entries(machine, entries_start, &cpu_count); read_info->entries_cpu = cpu_to_be16(cpu_count); - read_info->offset_cpu = cpu_to_be16(offsetof(ReadInfo, entries)); + read_info->offset_cpu = cpu_to_be16(offset_cpu); read_info->highest_cpu = cpu_to_be16(machine->smp.max_cpus - 1); read_info->ibc_val = cpu_to_be32(s390_get_ibc_val());
The start of the CPU entry region in the Read SCP Info response data is denoted by the offset_cpu field. As such, QEMU needs to begin creating entries at this address. This is in preparation for when Read SCP Info inevitably introduces new bytes that push the start of the CPUEntry field further away. Read CPU Info is unlikely to ever change, so let's not bother accounting for the offset there. Signed-off-by: Collin Walling <walling@linux.ibm.com> --- hw/s390x/sclp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)