Re: [PATCH] ppc: fixed incorrect name filed in vmstate_tlbemb_entry

[Peter Maydell]

On Tue, 20 Aug 2024 at 17:03, <nabiev.arman13@gmail.com> wrote:
>
> From: armanincredible <nabiev.arman13@gmail.com>
>
> Signed-off-by: armanincredible <nabiev.arman13@gmail.com>

[cc'd the ppc maintainers and list]



> ---
>  target/ppc/machine.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/target/ppc/machine.c b/target/ppc/machine.c
> index 731dd8df35..d433fd45fc 100644
> --- a/target/ppc/machine.c
> +++ b/target/ppc/machine.c
> @@ -621,7 +621,7 @@ static bool tlbemb_needed(void *opaque)
>  }
>
>  static const VMStateDescription vmstate_tlbemb = {
> -    .name = "cpu/tlb6xx",
> +    .name = "cpu/tlbemb",
>      .version_id = 1,
>      .minimum_version_id = 1,
>      .needed = tlbemb_needed,

This does look clearly a mistake, but on the other hand the
name field in a VMStateDescription is part of the on-the-wire
format, so changing it breaks migration compatibility.

Before we make this change we need to confirm that it is
not used on any machine types where we care about cross
version migration compat.

Alternatively if we need to keep the compatibility across
versions we could leave it as is and add a comment about
why. (I don't think we'll have a problem with incorrectly
interpreting a tlbemb as a tlb6xx, it will mismatch for
other reasons.)

thanks
-- PMM