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Date: Thu, 20 Nov 2014 10:00:52 +0000
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Message-ID: <20141120100051.GB5983@work-vm>
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Subject: Re: [Qemu-devel] [BUGFIX][PATCH for 2.2 v3 1/1] -machine
 vmport=auto: Fix handling of VMWare ioport emulation for xen
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Michael Tokarev <mjt@tls.msk.ru>, qemu-devel@nongnu.org, Don Slutz <dslutz@verizon.com>, Anthony Liguori <aliguori@amazon.com>, Stefan Hajnoczi <stefanha@redhat.com>

* Paolo Bonzini (pbonzini@redhat.com) wrote:
> 
> 
> On 20/11/2014 01:58, Eduardo Habkost wrote:
> >     if (pc_machine->vmport == VMPORT_AUTO) {
> >           no_vmport = xen_enabled();
> >     } else {
> >           no_vmport = (pc_machine->vmport == VMPORT_ON);
> >     }
> 
> I'm still not sure why the configuration should differ for "-M pc"
> depending on whether xen is enabled.

I think this goes back to:

commit 1611977c3d8fdbdac6090cbd1f5555cee4aed6d9
Author: Anthony PERARD <anthony.perard@citrix.com>
Date:   Tue May 3 17:06:54 2011 +0100

    pc, Disable vmport initialisation with Xen.
    
    This is because there is not synchronisation of the vcpu register
    between Xen and QEMU, so vmport can't work properly.
    
    This patch introduces no_vmport parameter to pc_basic_device_init.
    
    Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
    Signed-off-by: Alexander Graf <agraf@suse.de>

Dave

--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK