Re: [Qemu-devel] [RFC PATCH v3 18/24] xics_kvm: Don't enable KVM_CAP_IRQ_XICS if already enabled

[David Gibson]

On Wed, May 06, 2015 at 11:12:00AM +0530, Bharata B Rao wrote:
> On Tue, May 05, 2015 at 05:22:52PM +1000, David Gibson wrote:
> > On Fri, Apr 24, 2015 at 12:17:40PM +0530, Bharata B Rao wrote:
> > > When supporting CPU hot removal by parking the vCPU fd and reusing
> > > it during hotplug again, there can be cases where we try to reenable
> > > KVM_CAP_IRQ_XICS CAP for the vCPU for which it was already enabled.
> > > Introduce a boolean member in ICPState to track this and don't
> > > reenable the CAP if it was already enabled earlier.
> > > 
> > > This change allows CPU hot removal to work for sPAPR.
> > > 
> > > Signed-off-by: Bharata B Rao <address@hidden>
> > 
> > Do you actually need this?  Is there any harm in setting the
> > capability multiple times, or could you just ignore the "already set"
> > error?
> 
> We discussed this last time and concluded that this patch is needed.
> 
> Ref: http://lists.nongnu.org/archive/html/qemu-devel/2015-03/msg05361.html

Ah, ok.  Can you include the explanation from that message into the
commit message so I don't forget next time (and for the benefit of
other reviewers).

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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