Messages in this thread | | | Subject | Re: [PATCH v5 10/12] x86/xen: Bypass intr mode setup in enlighten_pv system | From | Dou Liyang <> | Date | Mon, 3 Jul 2017 15:17:53 +0800 |
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Hi Thomas,
At 07/03/2017 02:56 PM, Thomas Gleixner wrote: > On Mon, 3 Jul 2017, Dou Liyang wrote: >> At 07/03/2017 03:18 AM, Thomas Gleixner wrote: >>> On Fri, 30 Jun 2017, Dou Liyang wrote: >>> >>>> xen_smp_ops overwrites smp_prepare_cpus to xen_pv_smp_prepare_cpus >>>> which initializes interrupt itself. >>>> >>>> Touching the intr_mode_init causes unexpected results on the system. >>>> >>>> Bypass it in enlighten_pv system. >>> >>> So that's the wrong patch order then. You broke XEN at some point with your >>> changes. You need to prevent that breakage upfront not after the fact. >> >> Yes, I have considered to prevent that breakage in the patchset. >> >> Actually, Until the 11th patch, we put the intr_mode_init ahead of >> time, which will break XEN. >> >> Before the 11th patch, we just unify the code and do the preparation, >> Kernel will do the intr_mode_init like before, which will have no >> influence on XEN. >> >> So we put the patch here before 11th patch. > > Ok. That's good, but please explain it in the changelog. I had the > impression that this is fixing breakage you introduced earlier, but now > with your explanation it makes sense. So the patch order is correct. > > Something like this wants to be in the changelog: > > XEN PV overrides smp_prepare_cpus(). xen_pv_smp_prepare_cpus() > initializes interrupts in the XEN PV specific way and does not invoke > native_smp_prepare_cpus(). As a consequence, x86_init.intr_mode_init() is > not invoked either. > > The invocation of x86_init.intr_mode_init() will be moved from > native_smp_prepare_cpus() in a follow up patch to solve <INSERT > REASON/PROBLEM>. > > That move would cause the invocation of x86_init.intr_mode_init() for XEN > PV platforms. To prevent that, override the default x86_init.intr_mode_init() > callback with a noop().
Thank you very much for writing the changelog again. This is really the true purpose which I couldn't explain clearly.
I am testing my V6 patchset, will send it out soon.
Thanks,
dou. > > Thanks, > > tglx > > >
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