From: Aditya Gupta <adityag@linux.ibm.com>

Set the "Thread Register State Entry Size" that is required by firmware
(OPAL), to know size of memory to allocate to capture CPU state, in the
event of a crash

Reviewed-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
Tested-by: Shivang Upadhyay <shivangu@linux.ibm.com>
Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20260310124619.3909045-7-adityag@linux.ibm.com
Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
---
 hw/ppc/pnv.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 1513575b8f..3038b1626c 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -781,6 +781,30 @@ static void pnv_reset(MachineState *machine, ResetType type)
         _FDT((fdt_pack(fdt)));
     }
 
+    if (!pnv->mpipl_state.is_next_boot_mpipl) {
+        /*
+         * Set the "Thread Register State Entry Size", so that firmware can
+         * allocate enough memory to capture CPU state in the event of a
+         * crash
+         */
+
+        MpiplProcDumpArea proc_area;
+
+        proc_area.version = PROC_DUMP_AREA_VERSION_P9;
+        proc_area.thread_size = cpu_to_be32(sizeof(MpiplPreservedCPUState));
+
+        /* These are to be allocated & assigned by the firmware */
+        proc_area.alloc_addr = 0;
+        proc_area.alloc_size = 0;
+
+        /* These get assigned after crash, when QEMU preserves the registers */
+        proc_area.dest_addr = 0;
+        proc_area.act_size = 0;
+
+        cpu_physical_memory_write(PROC_DUMP_AREA_OFF, &proc_area,
+                sizeof(proc_area));
+    }
+
     cpu_physical_memory_write(PNV_FDT_ADDR, fdt, fdt_totalsize(fdt));
 
     /* Update machine->fdt with latest fdt */
-- 
2.52.0