Re: [Qemu-devel] [PATCH v2 2/2] memory: Split zones when do coalesced_io_del()

[Peter Xu <peterx@redhat.com>]

On Tue, Aug 20, 2019 at 02:35:15PM +0800, Peter Xu wrote:
> On Tue, Aug 20, 2019 at 08:24:12AM +0200, Paolo Bonzini wrote:
> > On 20/08/19 07:16, Peter Xu wrote:
> > > It is a workaround of current KVM's KVM_UNREGISTER_COALESCED_MMIO
> > > interface.  The kernel interface only allows to unregister an mmio
> > > device with exactly the zone size when registered, or any smaller zone
> > > that is included in the device mmio zone.  It does not support the
> > > userspace to specify a very large zone to remove all the small mmio
> > > devices within the zone covered.
> > > 
> > > Logically speaking it would be nicer to fix this from KVM side, though
> > > in all cases we still need to coop with old kernels so let's do this.
> > > 
> > > This patch has nothing to do with 3ac7d43a6fbb5d4a3 because this is
> > > probably broken from the very beginning when the
> > > KVM_UNREGISTER_COALESCED_MMIO interface is introduced in kernel.
> > > However to make the backport to stables easier, I'm still using the
> > > commit 3ac7d43a6fbb5d4a3 to track this problem because this will
> > > depend on that otherwise even additions of mmio devices won't work.
> > > 
> > > Fixes: 3ac7d43a6fbb5d4a3
> > > Signed-off-by: Peter Xu <peterx@redhat.com>
> > 
> > What about my comments to this patch? :)
> 
> I thought that comment was for patch 1 but wrongly replied to this
> patch 2... :)
> 
> Isn't that comment only valid if we still use the old patch 1?  With
> your suggestion, is that still needed to keep mr->coalesced untouched?

Oops, ignore this reply...  It's needed of course!  So it also
affecting this patch...

I'll prepare a v3 soon.

Regards,

-- 
Peter Xu