From: Harsh Prateek Bora <harshpb@linux.ibm.com>

lrdr-capacity contains phys field which communicates the maximum address
in bytes and therefore, the most memory that can be allocated to this
partition. This is usually populated when maxmem is provided alongwith
memory size on qemu command line. However since maxmem is an optional
param, this leads to bits being set to 0 in absence of maxmem param.
Fix this by initializing the respective bits as per total mem size in
such case.

Reported-by: Gaurav Batra <gbatra@us.ibm.com>
Tested-by: David Christensen <drc@linux.ibm.com>
Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Reviewed-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Link: https://lore.kernel.org/r/20250506042903.76250-1-harshpb@linux.ibm.com
Message-ID: <20250506042903.76250-1-harshpb@linux.ibm.com>
(cherry picked from commit 6285eebd3a5fea018eb51d696b51079f44dd1eb3)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index b0a0f8c689..98cf00af5b 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -907,6 +907,7 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, void *fdt)
     int rtas;
     GString *hypertas = g_string_sized_new(256);
     GString *qemu_hypertas = g_string_sized_new(256);
+    uint64_t max_device_addr = 0;
     uint32_t lrdr_capacity[] = {
         0,
         0,
@@ -917,13 +918,15 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, void *fdt)
 
     /* Do we have device memory? */
     if (MACHINE(spapr)->device_memory) {
-        uint64_t max_device_addr = MACHINE(spapr)->device_memory->base +
+        max_device_addr = MACHINE(spapr)->device_memory->base +
             memory_region_size(&MACHINE(spapr)->device_memory->mr);
-
-        lrdr_capacity[0] = cpu_to_be32(max_device_addr >> 32);
-        lrdr_capacity[1] = cpu_to_be32(max_device_addr & 0xffffffff);
+    } else if (ms->ram_size == ms->maxram_size) {
+        max_device_addr = ms->ram_size;
     }
 
+    lrdr_capacity[0] = cpu_to_be32(max_device_addr >> 32);
+    lrdr_capacity[1] = cpu_to_be32(max_device_addr & 0xffffffff);
+
     _FDT(rtas = fdt_add_subnode(fdt, 0, "rtas"));
 
     /* hypertas */
-- 
2.47.3