hw/i386/cxl: ensure maxram is greater than ram size for calculating cxl range

pc_get_device_memory_range() finds the device memory size by calculating the
difference between maxram and ram sizes. This calculation makes sense only when
maxram is greater than the ram size. Make sure we check for that before calling
pc_get_device_memory_range().

Signed-off-by: Ani Sinha <anisinha@redhat.com>
Message-Id: <20231011105335.42296-1-anisinha@redhat.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 6293f57a0c72865342b6b8157a3ef7f965767e89..dbaefa761764436a2c3c97d5024ec8107449150e 100644 (file)
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -781,10 +781,12 @@ static void pc_get_device_memory_range(PCMachineState *pcms,
 static uint64_t pc_get_cxl_range_start(PCMachineState *pcms)
 {
     PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
+    MachineState *ms = MACHINE(pcms);
     hwaddr cxl_base;
     ram_addr_t size;
 
-    if (pcmc->has_reserved_memory) {
+    if (pcmc->has_reserved_memory &&
+        (ms->ram_size < ms->maxram_size)) {
         pc_get_device_memory_range(pcms, &cxl_base, &size);
         cxl_base += size;
     } else {