Messages in this thread | | | Subject | Re: Questions on the task isolation patches | From | Chris Metcalf <> | Date | Thu, 22 Dec 2016 15:56:57 -0500 |
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On 12/20/2016 4:27 AM, Paolo Bonzini wrote: > On 16/12/2016 22:00, Chris Metcalf wrote: >> Sorry, I think I wasn't clear. Normally when you are running task >> isolated and you enter the kernel, you will get a fatal signal. The >> exception is if you call prctl itself (or exit), the kernel tolerates >> it without a signal, since obviously that's how you need to cleanly >> tell the kernel you are done with task isolation. > Running in a guest is pretty much the same as running in userspace. > Would it be possible to exclude the KVM_RUN ioctl as well? QEMU would > still have to run prctl when a CPU goes to sleep, and KVM_RUN would have > to enable/disable isolated mode when a VM executes HLT (which should > never happen anyway in NFV scenarios).
I think that probably makes sense. The flow would be that qemu executes first the prctl() for task isolation, then the KVM_RUN ioctl. We obviously can't do it in the other order, so we'd need to make task isolation tolerate KVM_RUN.
I won't try to do it for my next patch series (based on 4.10) though, since I'd like to get the basic support upstreamed before trying to extend it.
-- Chris Metcalf, Mellanox Technologies http://www.mellanox.com
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