On 30.05.14 18:03, Paolo Bonzini wrote:
Il 30/05/2014 17:58, Alexander Graf ha scritto:
Would new userspace with old kernel be able to detect that POWER8
support isn't quite complete?
It couldn't, no. It would try to run a guest - if it happens to work
we're lucky ;).
That's why I'm considering a revert.
Even then the only thing that would remotely be affected
by that one_reg rename is live migration (which just got a few more
fixes in this pull request).
Doesn't "info cpus" also do get/set one_reg?
Yeah, but WORT is not important enough to get listed.
What happens if it returns EINVAL? Also, reset should certainly try
to write all registers, what happens if one is missed.
If it returns EINVAL we just ignore the register.
Beyond the particular case of WORT, I'd just like to point out that
uapi/ changes need even more scrutiny from maintainers than usual. I
don't know exactly what checks Linus makes in my pull requests, but
uapi/ is at the top of the list of things he might look at, right
after the diffstat. :)
Consider that ONE_REG as experimental flagged :). Really, I am as
concerned as you are on ABI breakages, but in this case it's not worth
it. I'm not even sure any guest uses WORT at all. Linux doesn't seem to.
Alex
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