Messages in this thread | | | Date | Wed, 12 Dec 2012 21:31:29 -0700 | From | David Ahern <> | Subject | Re: [GIT PULL] perf changes for v3.8 |
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On 12/12/12 8:51 PM, Linus Torvalds wrote: > SO WHY DON'T YOU JUST DO THAT THEN? > > Disable PEBS on Vt-x enter and re-enable it on exit. End of story. > Exactly like you say.
See commit 26a4f3c0. But that was not enough. Requiring exclude_guest was another required piece. If you want to see the discussion: https://lkml.org/lkml/2012/7/9/264
> > But doing it this way was wrong. Switch that "exclude_guest" attribute > around, and admit that "H" was bogus, and that the right thing to do > was to add a "V" flag that sets the "force_guest" flag instead.
I understand this is annoying. Older binaries on newer kernels was the only case I could not fix. (I guess a message could be added kernel side to at least give a hint.) But the alternative -- based on code that has existed for some time -- is for older binaries to crash VMs.
David
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