| Message ID | 20200515222032.18838-6-walling@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | s390: Extended-Length SCCB & DIAGNOSE 0x318 | expand |
On 16/05/2020 00.20, 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. Note that the length of the Read SCP Info data > (data_len) denotes the same value as the cpu offset. > > This is in preparation of 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 | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c > index 5d6e98ae64..755f5f3fab 100644 > --- a/hw/s390x/sclp.c > +++ b/hw/s390x/sclp.c > @@ -113,13 +113,14 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb) > int rnsize, rnmax; > IplParameterBlock *ipib = s390_ipl_get_iplb(); > int data_len = get_read_scp_info_data_len(); > + CPUEntry *entries_start = (void *)sccb + data_len; > > if (!sccb_has_sufficient_len(sccb, machine->possible_cpus->len, data_len)) { > return; > } > > /* 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(data_len); > read_info->highest_cpu = cpu_to_be16(machine->smp.max_cpus - 1); > Reviewed-by: Thomas Huth <thuth@redhat.com>
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c index 5d6e98ae64..755f5f3fab 100644 --- a/hw/s390x/sclp.c +++ b/hw/s390x/sclp.c @@ -113,13 +113,14 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb) int rnsize, rnmax; IplParameterBlock *ipib = s390_ipl_get_iplb(); int data_len = get_read_scp_info_data_len(); + CPUEntry *entries_start = (void *)sccb + data_len; if (!sccb_has_sufficient_len(sccb, machine->possible_cpus->len, data_len)) { return; } /* 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(data_len); read_info->highest_cpu = cpu_to_be16(machine->smp.max_cpus - 1);
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. Note that the length of the Read SCP Info data (data_len) denotes the same value as the cpu offset. This is in preparation of 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 | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)