On 5/21/19 11:34 AM, Pierre Morel wrote:
This patch series implements PQAP/AQIC interception in KVM.
1) Data to handle GISA interrupt for AQIC
To implement this we need to add a new structure, vfio_ap_queue,
to be able to retrieve the mediated device associated with a queue
and specific values needed to register/unregister the interrupt
structures:
- APQN: to be able to issue the commands and search for queue
structures
- saved NIB : to keep track of the pin page for unpining it
- saved ISC : to unregister with the GIB interface
- matrix_mdev: to retrieve the associate matrix, the mediated device
and KVM
Specific handling bei keeping old values when re-registering is
needed because the guest could unregister interrupt in a invisble
manner bei issuing an un-interceptible RESET command.
Reset commands issued directly by the guest and indirectly when
removing the guest unpin the memory and deregister the ISC.
The vfio_ap_queue is associated to the ap_device during the probe
of the device and dissociated during the remove of the ap_device.
The vfio_ap_queue is associated to the matrix mediated device during
each interception of the AQIC command, so it does not need to be
dissociated until the guest is terminated.
The life of the vfio_ap_queue will be protected by the matrix_dev lock
to guaranty that no change can occur to the CRYCB or that devices can
not be removed when a vfio_ap_queue is in use.
2) KVM destroy race conditions
To make sure that KVM do not vanish and GISA is still available
when the VFIO_AP driver is in used we take a reference to KVM
during the opening of the mediated device and release it on
releasing the mediated device.
3) Interception of PQAP
The driver registers a hook structure to KVM providing:
- a pointer to a function implementing PQAP(AQIC) handling
- the reference to the module owner of the hook
On interception by KVM we do not change the behavior, returning
-EOPNOTSUPP to the user in the case AP instructions are not
supported by the host or by the guest.
Otherwise we verify the exceptions cases before trying to call
the vfio_ap hook.
In the case we do not find a hook we assume that the CRYCB has not
been setup for the guest and is empty.
4) Enabling and disabling the IRQ
When enabling the IRQ care is taken to unping the saved NIB.
When disabling IRQ care is taken to wait until the IRQ bit
of the queue status is cleared before unpining the NIB.
On RESET and before unpinning the NIB and unregistering the ISC
the IRQ is disabled using PQAP/AQIC even when a PQAP/APZQ have
been done.
5) Removing the AP device
Removing the AP device without having unassign it is clearly
discourage by the documentation.
The patch series does not check if the queue is used by a
guest. It only de-register the IRQ, unregister ISC and unpin
the NIB, then free the vfio_ap_queue.
6) Associated QEMU patch
There is a QEMU patch which is needed to enable the PQAP/AQIC
facility in the guest.
Posted in qemu-devel@xxxxxxxxxx as:
Message-Id: <1550146494-21085-1-git-send-email-pmorel@xxxxxxxxxxxxx>
7) Compatibility with Dynamic configuration patches
Tony, I did not rebase this series above the dynamic configuration
patches because:
- This series do the work it needs to do without having to take
care on the dynamic configuration.
- It is guarantied that interrupt will be shut off after removing
the APQueue device
- The dynamic configuration series is not converging.
Would you consider the following?
* Take dynconfig patch "s390: vfio-ap: wait for queue empty on queue
reset" and include it in your series. This patch modifies the
reset function to wait for queue empty.
* In dynconfig patch "s390: vfio-ap: handle bind and unbind of AP queue
device" the following functions are introduced:
void vfio_ap_mdev_probe_queue(struct ap_queue *queue)
void vfio_ap_mdev_remove_queue(struct ap_queue *queue)
The vfio_ap_mdev_probe_queue function is called from the vfio_ap
driver probe callback. You could embed the code you've introduced in
the probe callback there. Of course, you would need to return int
from the function for the -ENOMEM error.
The vfio_ap_mdev_remove_queue function is called from the vfio_ap
driver remove callback. You could embed the code you've introduced in
the remove callback there.
* Move your vfio_ap_irq_disable function to vfio_ap_ops.c and make it a
static function.
* Leave the vfio_ap_mdev_reset_queue function as a static function in
vfio_ap_ops.c
If you do the things above, then I can base the dynconfig series on
the IRQ series without much of a merge issue. What say you?
Note: I've included review comments for patch 3/4 to match the
suggestions above.
However Tony, the choice is your's, I won't be able to help
in a near future.
Pierre Morel (4):
s390: ap: kvm: add PQAP interception for AQIC
vfio: ap: register IOMMU VFIO notifier
s390: ap: implement PAPQ AQIC interception in kernel
s390: ap: kvm: Enable PQAP/AQIC facility for the guest
arch/s390/include/asm/kvm_host.h | 7 +
arch/s390/kvm/priv.c | 86 ++++++++
arch/s390/tools/gen_facilities.c | 1 +
drivers/s390/crypto/vfio_ap_drv.c | 34 ++-
drivers/s390/crypto/vfio_ap_ops.c | 379 +++++++++++++++++++++++++++++++++-
drivers/s390/crypto/vfio_ap_private.h | 15 ++
6 files changed, 514 insertions(+), 8 deletions(-)
