Re: [PATCH] perf(message): avoid buffer copy during command parsing

[Jarkko Sakkinen <jarkko@kernel.org>]

On Sun, Aug 31, 2025 at 06:01:45PM +0300, Jarkko Sakkinen wrote:
> `tpm_parse_command` copies handles and parameters to a fixed-size temporary
> 4 KiB buffer on the stack before invoking a command parser.
> 
> Introduce `TpmParseCommandBody` trait implemented by `tpm_struct!`,
> providing accessors for handles and parameters in the original command
> buffer, thus zeroing out the large stack allocation.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
> I plan to backport this also to 0.10.x branch, given signficancy.

This is something left out of initial stretch, which I've had in my mind
for some time. I postponed this change because stability was a priority
over performance at the time.

For the sake of symmetry I want to also rename `TpmHeaderCommand` as
`TpmCommandBuild`, make `TpmHeader` decoupled from that trait, and
finally change the constraint in `tpm_build_command` from `C:
TpmHeaderCommand` to `C: TpmHeader + TpmCommandBuild`.

This patch does not include that style change, given that it is first of
all logically distinct and further cannot be backported to the 0.10.x
branch.

BR, Jarkko