Re: XEN) vmx.c:2652:d1 Bad vmexit (reason 31) with Xen 4.0.1-rc7-pre (cs/ 23029)

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

On Thu, Mar 17, 2011 at 11:27:01PM +0000, Keir Fraser wrote:
> On 17/03/2011 20:26, "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com> wrote:
> 
> > 
> > The guest config is quite simple:
> > 
> > kernel = "/usr/lib/xen/boot/hvmloader"
> > builder='hvm'
> > memory=1024
> > #maxmem=1024
> > maxvcpus = 4
> > serial='pty'
> > vcpus = 2
> > disk = [ 'file:/mnt/lab/latest/root_image.iso,hdc:cdrom,r']
> > boot="dn"
> > vif = [ 'type=ioemu,model=e1000,mac=00:0F:4B:00:00:71, bridge=switch' ]
> > vfb = [ 'vnc=1, vnclisten=0.0.0.0,vncunused=1']
> > 
> > And this is what shows up after I do 'xm create hvm.xm' (or xl create hvm.xm).
> > 
> >   alloc irq_desc for 4223 on node -1
> >   alloc kstat_irqs on node -1
> > (XEN) vmx.c:2652:d1 Bad vmexit (reason 31)
> 
> Exit reason 31 is EXIT_REASON_MSR_READ. I don't see how that error can ever
> be printed for that exit reason. Could you do a bit of digging and see if
> you agree? The logic is straightforward enough -- the error comes from a

I do.. which is why I am puzzled by this. I am seeing this on two of my machines.
Interestingly enough - both of them are Intel and one of them is Nehelem, the other
is a Gulftown (I think). Let me double check that 4.0 did work on them for HVM guests.

There is also this that shows up as the guest is being created:

(XEN) [VT-D]iommu.c:1785: VT-d page table not sharing with EPT table

which I think is OK as the IOMMU is definitly turned off on one of the machines.


> default case in a switch statement, but the switch does explicitly handle
> EXIT_REASON_MSR_READ. There is also a exit_and_crash label for the default
> case, but EXIT_REASON_MSR_READ doesn't goto it afaics. So this is a weird
> and inexplicable bug, to me. :-)

Great :-)