Re: [Xen-devel] [Xen-users] Issues with vcpu-set

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2014-01-29 at 09:18 -0700, Yun Wang wrote:
> Here is the PV guest config
> #########################
> name = "centos65.pv"
> bootloader = "/usr/local/bin/pygrub"
> extra = "root=/dev/xvda"
> memory = 4096
> vcpus = 2
> vfb=[ "type=vnc, vncpass=123456" ]
> vif = [ 'mac=00:16:3e:54:02:01, bridge=xenbr0' ]
> disk = [ 'file:/vms/centos65_pv.img, xvda, w']

This will most likely use a qdisk backend, so this guest will have a
qemu instance running even though it is PV.

> ######################################
> 
> 
> The output of "xl -vvv vcpu-set"
> ########################
> 
> libxl: debug: libxl_qmp.c:696:libxl__qmp_initialize: connected to
> /var/run/xen/qmp-libxl-38

But we certainly shouldn't be doing this for such a guest, regardless of
whether a qemu is running for it.

Anthony -- looks like you forgot about the PV case in 62fe11fb --
libxl_set_vcpuonline shoulod use the xenstored version for such guests.
Can you send a fix please.

Ian.

> libxl: debug: libxl_qmp.c:296:qmp_handle_response: message type: qmp
> 
> libxl: debug: libxl_qmp.c:546:qmp_send_prepare: next qmp command: '{
> 
>     "execute": "qmp_capabilities",
> 
>     "id": 1
> 
> }
> 
> '
> 
> libxl: debug: libxl_qmp.c:296:qmp_handle_response: message type: return
> 
> libxl: debug: libxl_qmp.c:546:qmp_send_prepare: next qmp command: '{
> 
>     "execute": "cpu-add",
> 
>     "id": 2,
> 
>     "arguments": {
> 
>         "id": 0
> 
>     }
> 
> }
> 
> '
> 
> libxl: debug: libxl_qmp.c:296:qmp_handle_response: message type: error
> 
> libxl: error: libxl_qmp.c:287:qmp_handle_error_response: received an
> error message from QMP server: Not supported
> 
> xc: debug: hypercall buffer: total allocations:9 total releases:9
> 
> xc: debug: hypercall buffer: current allocations:0 maximum allocations:2
> 
> xc: debug: hypercall buffer: cache current size:2
> 
> xc: debug: hypercall buffer: cache hits:7 misses:2 toobig:0
> ######################################
> Again, this issue exists both on Xen-4.3.0 (official release) and
> Xen-4.4.0-rc1-25-g9a80d50
> 
> On Wed, Jan 29, 2014 at 7:45 AM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> > On Wed, 2014-01-29 at 07:38 -0700, Yun Wang wrote:
> >> So to fix the problem, I need to update the qemu version to version
> >> 1.7 or later?
> >
> > Yes. Or, AIUI, you can use the version of Qemu which is bundled with the
> > Xen releases.
> >
> >> BTW. I had this problem in both pvhvm and pv guest.
> >> Does pv guest rely on qemu also?
> >
> > It does not.
> >
> > If you are having an issue with a PV guest vcpu hotplug then it is not
> > the same underlying issue. Please report it separately with full logs,
> > config info etc.
> >
> > Ian.
> >



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