Re: [PATCH] riscv: Generate devicetree only after machine initialization is complete

[Daniel Henrique Barboza]

On 7/3/23 00:46, Guenter Roeck wrote:
> If the devicetree is created before machine initialization is complete,
> it misses dynamic devices. Specifically, the tpm device is not added
> to the devicetree file and is therefore not instantiated in Linux.
> Create devicetree in virt_machine_done() to solve the problem.
>
> Cc: Alistair Francis <alistair23@gmail.com>
> Fixes: 325b7c4e75 hw/riscv: Enable TPM backends
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>   hw/riscv/virt.c | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
> index ed4c27487e..08876284f5 100644
> --- a/hw/riscv/virt.c
> +++ b/hw/riscv/virt.c
> @@ -1248,6 +1248,11 @@ static void virt_machine_done(Notifier *notifier, void 
> *data)
>       uint64_t kernel_entry = 0;
>       BlockBackend *pflash_blk0;
>   
> +    /* create devicetree if not provided */
> +    if (!machine->dtb) {
> +        create_fdt(s, memmap);
> +    }
> +

I suggest moving the entire load/create DT code from virt_machine_init() to
the start of virt_machine_done():

    /* load/create device tree */
    if (machine->dtb) {
        machine->fdt = load_device_tree(machine->dtb, &s->fdt_size);
        if (!machine->fdt) {
            error_report("load_device_tree() failed");
            exit(1);
        }
    } else {
        create_fdt(s, memmap);
    }

This way we don't have to look in to 2 different functions to wonder what 
happens
in case machine->dtb is NULL.


Thanks,


Daniel


>       /*
>        * Only direct boot kernel is currently supported for KVM VM,
>        * so the "-bios" parameter is not supported when KVM is enabled.
> @@ -1508,15 +1513,13 @@ static void virt_machine_init(MachineState *machine)
>       }
>       virt_flash_map(s, system_memory);
>   
> -    /* load/create device tree */
> +    /* load device tree */
>       if (machine->dtb) {
>           machine->fdt = load_device_tree(machine->dtb, &s->fdt_size);
>           if (!machine->fdt) {
>               error_report("load_device_tree() failed");
>               exit(1);
>           }
> -    } else {
> -        create_fdt(s, memmap);
>       }
>   
>       s->machine_done.notify = virt_machine_done;