Re: [Xen-devel] [PATCH 2/3] xen/pv-on-hvm kexec: rebind virqs toexisting eventchannel ports

From: Olaf Hering
Date: Tue Aug 09 2011 - 05:30:20 EST

On Tue, Aug 09, Ian Campbell wrote:

> On Thu, 2011-08-04 at 17:20 +0100, Olaf Hering wrote:
> > During a kexec boot some virqs such as timer and debugirq were already
> > registered by the old kernel. The hypervisor will return -EEXISTS from
> > the new EVTCHNOP_bind_virq request and the BUG in bind_virq_to_irq()
> > triggers. Catch the -EEXISTS error and loop through all possible ports to find
> > what port belongs to the virq/cpu combo.
> Would it be better to proactively just query the status of all event
> channels early on, like you do in find_virq, and setup the irq info
> structures as appropriate? Rather than waiting for an -EEXISTS I mean.

Doing one hypercall in the common case is cheaper than doing a dozen in
the kexec case.

If you prefer I will rearrange this part and query first.

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