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


From: Peter Xu
Subject: Re: [Qemu-devel] [PATCH v2 2/2] memory: Split zones when do coalesced_io_del()
Date: Tue, 20 Aug 2019 14:35:15 +0800
User-agent: Mutt/1.11.4 (2019-03-13)

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 <address@hidden>
> 
> 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?

Regards,

-- 
Peter Xu



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