Re: [PATCH tip/core/rcu 02/20] x86: Use common outgoing-CPU-notification code

From: Boris Ostrovsky
Date: Wed Mar 04 2015 - 11:12:51 EST


On 03/04/2015 10:45 AM, David Vrabel wrote:
On 04/03/15 14:55, Boris Ostrovsky wrote:
In the meantime, it turned out that HVM guests are broken by this patch
(with our without changes that we've been discussing), because HVM CPUs
die with

static void xen_hvm_cpu_die(unsigned int cpu)
{
xen_cpu_die(cpu);
native_cpu_die(cpu);
}

Which means that cpu_wait_death() is called twice, and second call moves
the CPU to CPU_BROKEN.

The simple solution is to stop calling native_cpu_die() above but I'd
like to use common code in native_cpu_die(). I'll see if I can carve it
out without too much damage to x86.
If not really been following this thread but...

Would it be preferable to refactor xen_cpu_die() instead to factor out
its the cpu_wait_death() call?

That's essentially what I was going to do. Except that native_cpu_die() returns void so I'll need some common non-void code that lives in x86.

And then we can drop xen_hvm_cpu_die() and use xen_cpu_die() for all guests.

-boris

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