Re: [PATCH v4 1/3] hw/riscv/boot.c: calculate fdt size after fdt_pack()

From: Bin Meng <bmeng.cn@gmail.com>
To: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Cc: qemu-devel@nongnu.org, qemu-riscv@nongnu.org, alistair.francis@wdc.com
Subject: Re: [PATCH v4 1/3] hw/riscv/boot.c: calculate fdt size after fdt_pack()
Date: Sun, 29 Jan 2023 10:20:56 +0800	[thread overview]
Message-ID: <CAEUhbmUyG1_6Aea-kt_dWNvqJtFMojuuUwABBOe4oPrecwLdOw@mail.gmail.com> (raw)
In-Reply-To: <20230126135219.1054658-2-dbarboza@ventanamicro.com>

Hi Daniel,

On Thu, Jan 26, 2023 at 9:53 PM Daniel Henrique Barboza
<dbarboza@ventanamicro.com> wrote:
>
> fdt_pack() can change the fdt size, meaning that fdt_totalsize() can
> contain a now deprecated (bigger) value.

The commit message is a bit confusing.

The original code in this patch does not call fdt_pack(). So not sure
where the issue of "deprecated (bigger) value" happens?

>
> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> ---
>  hw/riscv/boot.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/hw/riscv/boot.c b/hw/riscv/boot.c
> index 3172a76220..a563b7482a 100644
> --- a/hw/riscv/boot.c
> +++ b/hw/riscv/boot.c
> @@ -287,8 +287,13 @@ uint64_t riscv_load_fdt(hwaddr dram_base, uint64_t mem_size, void *fdt)
>  {
>      uint64_t temp, fdt_addr;
>      hwaddr dram_end = dram_base + mem_size;
> -    int ret, fdtsize = fdt_totalsize(fdt);
> +    int ret = fdt_pack(fdt);
> +    int fdtsize;
>
> +    /* Should only fail if we've built a corrupted tree */
> +    g_assert(ret == 0);
> +
> +    fdtsize = fdt_totalsize(fdt);
>      if (fdtsize <= 0) {
>          error_report("invalid device-tree");
>          exit(1);

Regards,
Bin