Re: [PATCH v9 00/21] KVM: s390: enable zPCI for interpretive execution

[Matthew Rosato]

On 6/6/22 4:33 PM, Matthew Rosato wrote:
> Enable interpretive execution of zPCI instructions + adapter interruption
> forwarding for s390x KVM vfio-pci.  This is done by triggering a routine
> when the VFIO group is associated with the KVM guest, transmitting to
> firmware a special token (GISA designation) to enable that specific guest
> for interpretive execution on that zPCI device.  Load/store interpreation
> enablement is then controlled by userspace (based upon whether or not a
> SHM bit is placed in the virtual function handle).  Adapter Event
> Notification interpretation is controlled from userspace via a new KVM
> ioctl.
>
> By allowing intepretation of zPCI instructions and firmware delivery of
> interrupts to guests, we can reduce the frequency of guest SIE exits for
> zPCI.
>
>  From the perspective of guest configuration, you passthrough zPCI devices
> in the same manner as before, with intepretation support being used by
> default if available in kernel+qemu.
>
> Will follow up with a link the most recent QEMU series.
>
> Changelog v8->v9:
> - Rebase on top of 5.19-rc1, adjust ioctl and capability defines
> - s/kzdev = 0/kzdev = NULL/ (Alex)
> - rename vfio_pci_zdev_open to vfio_pci_zdev_open_device (Jason)
> - rename vfio_pci_zdev_release to vfio_pci_zdev_close_device (Jason)
> - make vfio_pci_zdev_close_device return void, instead WARN_ON or ignore
>    errors in lower level function (kvm_s390_pci_unregister_kvm) (Jason)
> - remove notifier accidentally left in struct zpci_dev + associated
>    include statment (Jason)
> - Remove patch 'KVM: s390: introduce CPU feature for zPCI Interpretation'
>    based on discussion in QEMU thread.

Ping -- I'm hoping this can make the next merge window, but there are 
still 2 patches left without any review tag (16 & 17).