diff mbox series

[v4,5/8] s390/sclp: use cpu offset to locate cpu entries

Message ID 20200624202312.28349-6-walling@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series s390: Extended-Length SCCB & DIAGNOSE 0x318 | expand

Commit Message

Collin Walling June 24, 2020, 8:23 p.m. UTC 
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>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
---
 hw/s390x/sclp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index 1feba6f692..518f630938 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -108,13 +108,14 @@  static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb)
     int rnsize, rnmax;
     IplParameterBlock *ipib = s390_ipl_get_iplb();
     int offset_cpu = get_read_scp_info_offset_cpu();
+    CPUEntry *entries_start = (void *)sccb + offset_cpu;
 
     if (!sccb_verify_length(sccb, machine->possible_cpus->len, offset_cpu)) {
         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(offset_cpu);
     read_info->highest_cpu = cpu_to_be16(machine->smp.max_cpus - 1);