Re: [Qemu-devel] [PATCH] s390x/vfio-ap: Implement hot plug/unplug of vfio-ap device

[Tony Krowiak <akrowiak@linux.ibm.com>]

On 1/8/19 11:01 AM, Tony Krowiak wrote:
> Introduces hot plug/unplug support for the vfio-ap device. Note that only one
> vfio-ap device can be attached to the ap-bus, so a vfio-ap device can only be
> hot plugged if the '-device vfio-ap,sysfsdev=$path_to_mdev' option is not
> specified on the QEMU command line.
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Reviewed-by: Pierre Morel<pmorel@linux.ibm.com>
> Tested-by: Pierre Morel<pmorel@linux.ibm.com>
> ---
>   hw/s390x/ap-bridge.c | 12 +++++++++++-
>   hw/vfio/ap.c         |  2 +-
>   2 files changed, 12 insertions(+), 2 deletions(-)
> 

Please note: During testing of this patch I discovered a bug whereby an
attempt to plug in a vfio-ap device subsequent to an unplug of the
device will result in the following error:

error: Failed to attach device from /root/conf/vfio-ap.xml
error: internal error: unable to execute QEMU command 'device_add': No 
'ap-bus' bus found for device 'vfio-ap'

I wrote a patch for this bug:
Message ID: <1545062250-7573-1-git-send-email-akrowiak@linux.ibm.com>