riscv/virt: Support using pflash via -blockdev option

Currently, pflash devices can be configured only via -pflash
or -drive options. This is the legacy way and the
better way is to use -blockdev as in other architectures.
libvirt also has moved to use -blockdev method.

To support -blockdev option, pflash devices need to be
created in instance_init itself. So, update the code to
move the virt_flash_create() to instance_init. Also, use
standard interfaces to detect whether pflash0 is
configured or not.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reported-by: Andrea Bolognani <abologna@redhat.com>
Tested-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230601045910.18646-3-sunilvl@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

hw/riscv/virt.c

@@ -1246,6 +1246,7 @@ static void virt_machine_done(Notifier *notifier, void *data)
     const char *firmware_name = riscv_default_firmware_name(&s->soc[0]);
     uint32_t fdt_load_addr;
     uint64_t kernel_entry = 0;
+    BlockBackend *pflash_blk0;
 
     /*
      * Only direct boot kernel is currently supported for KVM VM,
@@ -1266,7 +1267,8 @@ static void virt_machine_done(Notifier *notifier, void *data)
     firmware_end_addr = riscv_find_and_load_firmware(machine, firmware_name,
                                                      start_addr, NULL);
 
-    if (drive_get(IF_PFLASH, 0, 0)) {
+    pflash_blk0 = pflash_cfi01_get_blk(s->flash[0]);
+    if (pflash_blk0) {
         if (machine->firmware && !strcmp(machine->firmware, "none") &&
             !kvm_enabled()) {
             /*
@@ -1499,8 +1501,6 @@ static void virt_machine_init(MachineState *machine)
     sysbus_create_simple("goldfish_rtc", memmap[VIRT_RTC].base,
         qdev_get_gpio_in(mmio_irqchip, RTC_IRQ));
 
-    virt_flash_create(s);
-
     for (i = 0; i < ARRAY_SIZE(s->flash); i++) {
         /* Map legacy -drive if=pflash to machine properties */
         pflash_cfi01_legacy_drive(s->flash[i],
@@ -1527,6 +1527,8 @@ static void virt_machine_instance_init(Object *obj)
 {
     RISCVVirtState *s = RISCV_VIRT_MACHINE(obj);
 
+    virt_flash_create(s);
+
     s->oem_id = g_strndup(ACPI_BUILD_APPNAME6, 6);
     s->oem_table_id = g_strndup(ACPI_BUILD_APPNAME8, 8);
     s->acpi = ON_OFF_AUTO_AUTO;