Re: [Qemu-devel] [PATCH] s390x/cpumodel: Set up CPU model for AQIC interception

[Cornelia Huck <cohuck@redhat.com>]

On Fri,  5 Jul 2019 17:32:49 +0200
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> From: Pierre Morel <pmorel@linux.ibm.com>
> 
> Let's add support for the AP-Queue interruption facility to the CPU
> model.
> 
> The S390_FEAT_AP_QUEUE_INTERRUPT_CONTROL, CPU facility indicates
> whether the PQAP instruction with the AQIC command is available
> to the guest.
> This feature will be enabled only if the AP instructions are
> available on the linux host and AQIC facility is installed on
> the host.
> 
> This feature must be turned on from userspace to intercept AP
> instructions on the KVM guest. The QEMU command line to turn
> this feature on looks something like this:
> 
>     qemu-system-s390x ... -cpu xxx,apqi=on ...
> or
>     ... -cpu host
> 
> Right now AP pass-through devices do not support migration,
> which means that we do not have to take care of migrating
> the interrupt data:
> virsh migrate apguest --live qemu+ssh://root@target.lan/system
> error: Requested operation is not valid: domain has assigned non-USB host devices
> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> [rebase to newest qemu and fixup description]
> ---
>  target/s390x/cpu_features_def.inc.h | 1 +
>  target/s390x/cpu_models.c           | 1 +
>  target/s390x/gen-features.c         | 1 +
>  3 files changed, 3 insertions(+)

While technically a tad late for 4.1, this is a small and
straightforward patch (that already had been on the list earlier), so I
went ahead and applied it.