From ad8b922ab3ce8e1c430be7764df96c866b1b42ad Mon Sep 17 00:00:00 2001 From: Collin Walling Date: Tue, 15 Sep 2020 15:44:13 -0400 Subject: [PATCH 5/9] s390/sclp: use cpu offset to locate cpu entries 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 Reviewed-by: Thomas Huth Reviewed-by: Cornelia Huck Reviewed-by: Claudio Imbrenda Message-Id: <20200915194416.107460-6-walling@linux.ibm.com> Signed-off-by: Cornelia Huck --- hw/s390x/sclp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c index 0cb9c72313..6745bfdf1e 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()); -- 2.31.1