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

[Daniel Henrique Barboza]

On 7/3/23 04:46, Philippe Mathieu-Daudé wrote:
> On 3/7/23 05:46, 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.
>
> This makes sense, but what about the other archs/machines?
> Shouldn't we fix this generically?

As far as other archs goes I can say that ARM isn't affected by it because
the fdt creation is done by arm_load_dtb() during virt_machine_done time.
I'm not aware of how x86 handles TPM. And pseries/ppc64 does a completely
different thing (per usual).

Inside hw/riscv the only TPM capable board is 'virt'. So I think this patch
has an adequate scope.


Thanks,


Daniel


> > 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);
> > +    }
> > +
> >       /*
> >        * 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;