hw/core/machine: diagnose wrapping of maxmem

The 'maxmem' parameter parsed on the command line is held in uint64_t
and then assigned to the MachineState field that is 'ram_addr_t'. This
assignment will wrap on 32-bit hosts, silently changing the user's
config request if it were over-sized.

Improve the existing diagnositics for validating 'size', and add the
same diagnostics for 'maxmem'

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Tested-by: Ani Sinha <anisinha@redhat.com>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Message-ID: <20241127114057.255995-1-berrange@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

diff --git a/hw/core/machine.c b/hw/core/machine.c
index a35c4a8faecbf267efbe783a0dc671847a48e7e9..f29fe959647f52586d81969e203d2995a5855bf3 100644 (file)
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -598,11 +598,19 @@ static void machine_set_mem(Object *obj, Visitor *v, const char *name,
         mem->size = mc->fixup_ram_size(mem->size);
     }
     if ((ram_addr_t)mem->size != mem->size) {
-        error_setg(errp, "ram size too large");
+        error_setg(errp, "ram size %llu exceeds permitted maximum %llu",
+                   (unsigned long long)mem->size,
+                   (unsigned long long)RAM_ADDR_MAX);
         goto out_free;
     }
 
     if (mem->has_max_size) {
+        if ((ram_addr_t)mem->max_size != mem->max_size) {
+            error_setg(errp, "ram size %llu exceeds permitted maximum %llu",
+                       (unsigned long long)mem->max_size,
+                       (unsigned long long)RAM_ADDR_MAX);
+            goto out_free;
+        }
         if (mem->max_size < mem->size) {
             error_setg(errp, "invalid value of maxmem: "
                        "maximum memory size (0x%" PRIx64 ") must be at least "