Re: [Qemu-devel] iommu emulation

[Peter Xu <peterx@redhat.com>]

On Thu, Mar 02, 2017 at 05:20:19PM -0500, Bandan Das wrote:
> Jintack Lim <jintack@cs.columbia.edu> writes:
> 
> > [cc Bandan]
> >
> > On Tue, Feb 21, 2017 at 5:33 AM, Jintack Lim <jintack@cs.columbia.edu>
> > wrote:
> >
> >>
> >>
> >> On Wed, Feb 15, 2017 at 9:47 PM, Alex Williamson <
> >> alex.williamson@redhat.com> wrote:
> ...
> >>
> >
> > I've tried another network device on a different machine. It has "Intel
> > Corporation 82599ES 10-Gigabit SFI/SFP+ Network Connection" ethernet
> > controller. I got the same problem of getting the network device
> > initialization failure in L2. I think I'm missing something since I heard
> > from Bandan that he had no problem to assign a device to L2 with ixgbe.
> >
> > This is the error message from dmesg in L2.
> >
> > [    3.692871] ixgbe: Intel(R) 10 Gigabit PCI Express Network Driver -
> > version 4.2.1-k
> > [    3.697716] ixgbe: Copyright (c) 1999-2015 Intel Corporation.
> > [    3.964875] ixgbe 0000:00:02.0: HW Init failed: -12
> > [    3.972362] ixgbe: probe of 0000:00:02.0 failed with error -12
> >
> > I checked that L2 indeed had that device.
> > root@guest0:~# lspci
> > 00:00.0 Host bridge: Intel Corporation 82G33/G31/P35/P31 Express DRAM
> > Controller
> > 00:01.0 VGA compatible controller: Device 1234:1111 (rev 02)
> > 00:02.0 Ethernet controller: Intel Corporation 82599ES 10-Gigabit SFI/SFP+
> > Network Connection (rev 01)
> 
> Jintack, any progress with this ?
> 
> I am testing on a X540-AT2 and I see a different behavior. It appears
> config succeeds but the driver keeps resetting the device due to a Tx
> hang:
> 
> [ 568.612391 ] ixgbe 0000:00:03.0 enp0s3: tx hang 38 detected on queue 0,
> resetting adapter
> [ 568.612393 ]  ixgbe 0000:00:03.0 enp0s3: initiating reset due to tx
> timeout
> [ 568.612397 ]  ixgbe 0000:00:03.0 enp0s3: Reset adapter
> 
> This may be device specific but I think the actual behavior you see is
> also dependent on the ixgbe driver in the guest. Are you on a recent
> kernel ? Also, can you point me to the hack (by Peter) that you have
> mentioned above ?

Hi, Bandan,

Are you using the vtd vfio v7 series or another branch?

If it's the upstream one... just a note that we need to make sure
"-device intel-iommu" be the first device specified in QEMU command
line parameters (need to before "-device vfio-pci,..."). Thanks,

-- peterx