[PATCH v2 13/25] hw/s390x/ipl: Set iplb->len to maximum length of IPL Parameter Block

[Zhuoying Cai]

The IPL Information Report Block (IIRB) immediately follows the IPL
Parameter Block (IPLB).

The IPLB struct is allocated 4KB in memory, and iplb->len indicates
the amount of memory currently used by the IPLB.

To ensure proper alignment of the IIRB and prevent overlap, set
iplb->len to the maximum length of the IPLB, allowing alignment
constraints to be determined based on its size.

Signed-off-by: Zhuoying Cai <zycai@linux.ibm.com>
---
 hw/s390x/ipl.c | 6 +++---
 hw/s390x/ipl.h | 1 +
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index 8ac0cee73d..d1a972ac8d 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -459,7 +459,7 @@ static bool s390_build_iplb(DeviceState *dev_st, 
IplParameterBlock *iplb)
             if (scsi_lp && strlen(scsi_lp) > 0) {
                 lp = scsi_lp;
             }
-            iplb->len = cpu_to_be32(S390_IPLB_MIN_QEMU_SCSI_LEN);
+            iplb->len = cpu_to_be32(S390_IPLB_MAX_LEN);
             iplb->blk0_len =
                 cpu_to_be32(S390_IPLB_MIN_QEMU_SCSI_LEN - 
S390_IPLB_HEADER_LEN);
             iplb->pbt = S390_IPL_TYPE_QEMU_SCSI;
@@ -470,14 +470,14 @@ static bool s390_build_iplb(DeviceState *dev_st, 
IplParameterBlock *iplb)
             iplb->scsi.ssid = ccw_dev->sch->ssid & 3;
             break;
         case CCW_DEVTYPE_VFIO:
-            iplb->len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
+            iplb->len = cpu_to_be32(S390_IPLB_MAX_LEN);
             iplb->pbt = S390_IPL_TYPE_CCW;
             iplb->ccw.devno = cpu_to_be16(ccw_dev->sch->devno);
             iplb->ccw.ssid = ccw_dev->sch->ssid & 3;
             break;
         case CCW_DEVTYPE_VIRTIO_NET:
         case CCW_DEVTYPE_VIRTIO:
-            iplb->len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
+            iplb->len = cpu_to_be32(S390_IPLB_MAX_LEN);
             iplb->blk0_len =
                 cpu_to_be32(S390_IPLB_MIN_CCW_LEN - S390_IPLB_HEADER_LEN);
             iplb->pbt = S390_IPL_TYPE_CCW;
diff --git a/hw/s390x/ipl.h b/hw/s390x/ipl.h
index 3e7190c7d8..ed29881dfa 100644
--- a/hw/s390x/ipl.h
+++ b/hw/s390x/ipl.h
@@ -101,6 +101,7 @@ QEMU_BUILD_BUG_MSG(offsetof(S390IPLState, iplb) & 3, 
"alignment of iplb wrong");
 #define S390_IPLB_MIN_CCW_LEN 200
 #define S390_IPLB_MIN_FCP_LEN 384
 #define S390_IPLB_MIN_QEMU_SCSI_LEN 200
+#define S390_IPLB_MAX_LEN 4096
 
 static inline bool diag_parm_addr_valid(uint64_t addr, size_t size, bool write)
 {
-- 
2.49.0