microvm: drop max-ram-below-4g support

Not useful for microvm and allows users to shoot themself
into the foot (make ram + mmio overlap).
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NIgor Mammedov <imammedo@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Message-id: 20200529073957.8018-3-kraxel@redhat.com

hw/i386/microvm.c

@@ -173,25 +173,6 @@ static void microvm_memory_init(MicrovmMachineState *mms)
     ram_addr_t lowmem = 0xc0000000; /* 3G */
     int i;
 
-    /*
-     * Handle the machine opt max-ram-below-4g.  It is basically doing
-     * min(qemu limit, user limit).
-     */
-    if (!x86ms->max_ram_below_4g) {
-        x86ms->max_ram_below_4g = 4 * GiB;
-    }
-    if (lowmem > x86ms->max_ram_below_4g) {
-        lowmem = x86ms->max_ram_below_4g;
-        if (machine->ram_size - lowmem > lowmem &&
-            lowmem & (1 * GiB - 1)) {
-            warn_report("There is possibly poor performance as the ram size "
-                        " (0x%" PRIx64 ") is more then twice the size of"
-                        " max-ram-below-4g (%"PRIu64") and"
-                        " max-ram-below-4g is not a multiple of 1G.",
-                        (uint64_t)machine->ram_size, x86ms->max_ram_below_4g);
-        }
-    }
-
     if (machine->ram_size > lowmem) {
         x86ms->above_4g_mem_size = machine->ram_size - lowmem;
         x86ms->below_4g_mem_size = lowmem;