Re: [Qemu-devel] iommu emulation

[Bandan Das <bsd@redhat.com>]

Peter Xu <peterx@redhat.com> writes:

> On Thu, Mar 02, 2017 at 05:20:19PM -0500, Bandan Das wrote:
>> Jintack Lim <jintack@cs.columbia.edu> writes:
>> 
>> > [cc Bandan]
>> >
...
>> 
>> 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?

Thanks for the tip. Jintack pointed me to your repo and I am using v7
from there.

> 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