Re: VMX status report. Xen:25334 & Dom0:568b445...

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, May 23, 2012 at 08:21:24AM +0000, Ren, Yongjie wrote:
> > -----Original Message-----
> > From: Ian Campbell [mailto:Ian.Campbell@citrix.com]
> > Sent: Tuesday, May 22, 2012 4:32 PM
> > To: Ren, Yongjie
> > Cc: Konrad Rzeszutek Wilk; Wu, GabrielX; Liu, SongtaoX; Zhou, Chao;
> > 'xen-devel@lists.xen.org'
> > Subject: Re: [Xen-devel] VMX status report. Xen:25334 & Dom0:568b445...
> > 
> > On Tue, 2012-05-22 at 08:19 +0100, Ren, Yongjie wrote:
> > > > -----Original Message-----
> > > > From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com]
> > > > Sent: Monday, May 21, 2012 10:22 PM
> > > > To: Wu, GabrielX
> > > > Cc: 'xen-devel@lists.xen.org'; Ren, Yongjie; Liu, SongtaoX; Zhou, Chao
> > > > Subject: Re: [Xen-devel] VMX status report. Xen:25334 &
> > Dom0:568b445...
> > > >
> > > > On Mon, May 21, 2012 at 03:05:28AM +0000, Wu, GabrielX wrote:
> > > > > Hi all,
> > > > >
> > > > > This is the test report of xen-unstable tree.
> > > > > There are two issues found and one issue got fixed.
> > > > >
> > > > > Version Info:
> > > > >
> > > >
> > ============================================================
> > > > =====
> > > > > xen-changeset:   25334:f8279258e3c9
> > > > > Dom0:          linux.git  3.4.0-rc7+ (commit: 568b445...)
> > > > >
> > > >
> > ============================================================
> > > > =====
> > > > >
> > > > > New issues(2)
> > > > > ==============
> > > > > 1. long stop during the guest boot process with qcow image
> > > > >   http://bugzilla.xen.org/bugzilla/show_bug.cgi?id=1821
> > > > > 2. vcpu-set doesn't take effect on guest
> > > > >   http://bugzilla.xen.org/bugzilla/show_bug.cgi?id=1822
> > > >
> > > > Does it work if you (in the guest) do
> > > > echo 1 > /sys/../cpu9/online ?
> > > >
> > > The problem is there's no hot-add vCPU in /sys/devices/system/cpu
> > directory.
> > > e.g. I start a guest with 2 vCPU,
> > 
> > Do you mean with maxvcpu=4 vcpus=2 in your config?
> > 
> > >  then I run command 'xl vcpu-set $domID 4'.
> > 
> > >     There are only 2 CPUs(cpu0 and cpu1) listed in
> > /sys/devices/system/cpu directory.
> > 
> > The bugzilla says "But it'll effect to dom0.", does this mean that
> > 	xl vcpu-set domU 4
> > will actually set dom0 to 12 vcpus? Or does it just mean that
> > 	xl vcpu-set 0 4
> > works where
> > 	xl vcpu-set domU 4
> > does not?
> > 
> 'xl vcpu-set 0 4' works well for dom0 in some circumstances.
> 'xl vcpu-set domU 4' doesn't work for dumU at all.
> 
> 'xl vcpu-set' for dom0 also has a bug. 
> You can use 'xl vcpu-set' command to decrease vCPU number for dom0;
> but when you try to increase its number you might meet dom0 panic.
> Please look at my comment #2 in the following BZ.
> http://bugzilla.xen.org/bugzilla/show_bug.cgi?id=1730

That should have been fixed in 3.4 by cf405ae612b0f7e2358db7ff594c0e94846137aa
"xen/smp: Fix crash when booting with ACPI hotplug CPUs."