Re: [PATCH 0/4] hw/s390x: Alias @dump-skeys -> @dump-s390-skey and deprecate
* Thomas Huth (thuth(a)redhat.com) wrote:
On 30/05/2024 09.45, Philippe Mathieu-Daudé wrote:
> We are trying to unify all qemu-system-FOO to a single binary.
> In order to do that we need to remove QAPI target specific code.
>
> @dump-skeys is only available on qemu-system-s390x. This series
> rename it as @dump-s390-skey, making it available on other
> binaries. We take care of backward compatibility via deprecation.
>
> Philippe Mathieu-Daudé (4):
> hw/s390x: Introduce the @dump-s390-skeys QMP command
> hw/s390x: Introduce the 'dump_s390_skeys' HMP command
> hw/s390x: Deprecate the HMP 'dump_skeys' command
> hw/s390x: Deprecate the QMP @dump-skeys command
Why do we have to rename the command? Just for the sake of it? I think
renaming HMP commands is maybe ok, but breaking the API in QMP is something
you should consider twice.
And even if we decide to rename ... maybe we should discuss whether it makes
sense to come up with a generic command instead: As far as I know, ARM also
has something similar, called MTE. Maybe we also want to dump MTE keys one
day? So the new command should maybe be called "dump-memory-keys" instead?
I think there are at least two different concepts; but I agree it would be
nice to keep a single command for matching concepts across different architectures;
I can't say I know the details of any, but:
a) Page table things - I think x86 PKRU/PKEY (???) is a page table thing
where pages marked a special way are associated with keys.
That sounds similar to what the skeys are???
b) Upper bit things - where you steal a few bits from the virtual address
and then use that to associate some security; I think that's closer
to what MTE is isn't it?
I'm not sure the two fit in the same command.
Dave
Or should it maybe rather be an option to the existing
"dump-guest-memory"
command instead?
Thomas
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