hw/arm: Use MachineClass->default_nic in the sbsa-ref machine

Mark the default NIC via the new MachineClass->default_nic setting
so that the machine-defaults code in vl.c can decide whether the
default NIC is usable or not (for example when compiling with the
"--without-default-devices" configure switch).

Message-Id: <20230524082037.1620952-1-thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>

hw/arm/sbsa-ref.c

@@ -596,6 +596,7 @@ static void create_pcie(SBSAMachineState *sms)
     hwaddr size_mmio_high = sbsa_ref_memmap[SBSA_PCIE_MMIO_HIGH].size;
     hwaddr base_pio = sbsa_ref_memmap[SBSA_PCIE_PIO].base;
     int irq = sbsa_ref_irqmap[SBSA_PCIE];
+    MachineClass *mc = MACHINE_GET_CLASS(sms);
     MemoryRegion *mmio_alias, *mmio_alias_high, *mmio_reg;
     MemoryRegion *ecam_alias, *ecam_reg;
     DeviceState *dev;
@@ -641,7 +642,7 @@ static void create_pcie(SBSAMachineState *sms)
             NICInfo *nd = &nd_table[i];
 
             if (!nd->model) {
-                nd->model = g_strdup("e1000e");
+                nd->model = g_strdup(mc->default_nic);
             }
 
             pci_nic_init_nofail(nd, pci->bus, nd->model, NULL);
@@ -858,6 +859,7 @@ static void sbsa_ref_class_init(ObjectClass *oc, void *data)
     mc->minimum_page_bits = 12;
     mc->block_default_type = IF_IDE;
     mc->no_cdrom = 1;
+    mc->default_nic = "e1000e";
     mc->default_ram_size = 1 * GiB;
     mc->default_ram_id = "sbsa-ref.ram";
     mc->default_cpus = 4;