Re: [PATCH v4 1/2] x86: return modified setup_data only if read as memory, not as file

[Jason A. Donenfeld]

Hi Paolo,

On Wed, Sep 21, 2022 at 10:59 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
> Just a small comment, addr should be little-endian (see
> fw_cfg_add_i32).  It's not used outside x86_load_linux, so it is
> possible to just use cpu_to_le32 there.

Oh, shucks: I thought about this and then forgot to do it. Thanks for
catching it.

> Also I think it's cleaner if a reset callback puts the value back to
> zero. fw_cfg already has fw_cfg_machine_reset, so perhaps the easiest
> way is to add a FWCfgCallback reset_cb argument to just
> fw_cfg_add_bytes_callback. If I am missing something and it's not
> necessary I can do the cpu_to_le32 change myself or wait for you; in
> any case I'll wait for either your ack or a v5.

Actually, the idea is for the change to be permanent, since that
represents how the system has actually been booted. Are there
substantial changes possible to the firmware configuration on
fw_cfg_machine_reset() that setting this back how it was would make a
difference? Or do we benefit from having some consistency?

> By the way, does this supersede v1..v3 that use the new protocol (I'd
> guess so from the presence of the same 2/2 patch), or are the two
> patches doing belts-and-suspenders?

This v4 supersedes everything else.

Jason