From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wei Liu <wei.liu2@citrix.com>
Subject: Re: QEMU bumping memory bug analysis
Date: Tue, 9 Jun 2015 11:17:03 +0100
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To: George Dunlap <george.dunlap@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>, Ian Campbell <ian.campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>, Ian Jackson <Ian.Jackson@eu.citrix.com>, Don Slutz <dslutz@verizon.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
List-Id: xen-devel@lists.xenproject.org

On Tue, Jun 09, 2015 at 11:00:12AM +0100, George Dunlap wrote:
> >> I think that qemu needs to tell libxl how much memory it is using for
> >> all of its needs -- including option ROMs.  (See my example below.)  For
> >> older qemus we can just make some assumptions like we always have.
> >>
> > 
> > I am happy with this.  Note: I think libxl could determine this number
> > now without QEMU changes.  However it does depend on no other thread
> > changing a "staring" domain's memory while libxl is calculating this.
> > 
> >> I do think it would make sense to have the hvmloader amount listed
> >> somewhere explicitly.  I'm not sure how often hvmloader may need to
> >> change the amount it uses for itself.
> >>
> > 
> > hvmloader does yet a different method.  If
> > xc_domain_populate_physmap_exact() fails, it reduces guest RAM (if my
> > memory is correct).
> 
> This makes me wonder if we could make qemu do the same thing.
> 

I don't think so, because QEMU can't adjust hvm_info.

>  -George