Re: [PATCH 6/7] s390: vfio-ap: handle dynamic config/deconfig of AP adapter

From: Tony Krowiak
Date: Mon Apr 15 2019 - 14:52:57 EST

On 4/11/19 5:03 PM, Tony Krowiak wrote:
Once an APQN is assigned to an mdev device it will remained assigned until
it is explicitly unassigned from the mdev device. The associated AP queue
devices, however, can come and go due to failures or deliberate actions by
a sysadmin. For example, a sysadmin can dynamically remove an AP adapter
card using the SE or by executing an SCLP command. This patch refactors
the probe and remove callbacks of the vfio_ap driver to handle dynamic
changes as follows:

* Probe callback changes:

If the APQN of the queue being probed is assigned to an mdev device, the
mdev device is in use by a guest, and the APQN is not set in the guest's
CRYCB, the CRYCB will be dynamically updated to give the guest access to
the queue.

* Remove callback changes:

If the APQN of the queue being removed is assigned to an mdev device,
the mdev
device is in use by a guest, and the APQN is set in the guest's CRYCB,
the CRYCB will be dynamically updated to remove the guest's access to
the adapter card associated with the queue. Keep in mind, the
architecture does not provide a way to remove access to a single queue
unless only one queue is in the guest's configuration, so it was decided
that it makes more sense to unplug the adapter from the guest.

The APQN of the queue being removed will remain assigned to the mdev
device should the queue be dynamically returned to the configuration.
The queue will also be reset prior to returning control to the caller
(a.k.a., the AP bus).

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 2 ++
arch/s390/kvm/kvm-s390.c | 37 +++++++++++++++++++
drivers/s390/crypto/vfio_ap_drv.c | 16 +++++++--
drivers/s390/crypto/vfio_ap_ops.c | 67 +++++++++++++++++++++++++++++++++--
drivers/s390/crypto/vfio_ap_private.h | 2 ++
5 files changed, 120 insertions(+), 4 deletions(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index c47e22bba87f..0ce5d9b0df59 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -895,6 +895,8 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
void kvm_arch_crypto_clear_masks(struct kvm *kvm);
void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
unsigned long *aqm, unsigned long *adm);
+int kvm_arch_crypto_test_masks(struct kvm *kvm, unsigned long *apm,
+ unsigned long *aqm, unsigned long *adm);
extern int sie64a(struct kvm_s390_sie_block *, u64 *);
extern char sie_exit;
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 4638303ba6a8..5f423cdd29ba 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2217,6 +2217,43 @@ static void kvm_s390_set_crycb_format(struct kvm *kvm)
kvm->arch.crypto.crycbd |= CRYCB_FORMAT1;
}
+int kvm_arch_crypto_test_masks(struct kvm *kvm, unsigned long *apm,
+ unsigned long *aqm, unsigned long *adm)
+{
+ int ret;
+ struct kvm_s390_crypto_cb *crycb = kvm->arch.crypto.crycb;
+
+ switch (kvm->arch.crypto.crycbd & CRYCB_FORMAT_MASK) {
+ case CRYCB_FORMAT2: /* APCB1 use 256 bits */
+ ret = bitmap_equal(apm, (unsigned long *)crycb->apcb1.apm, 256);
+ VM_EVENT(kvm, 3, "TEST CRYCB: apm %016lx %016lx %016lx %016lx",
+ apm[0], apm[1], apm[2], apm[3]);
+ ret &= bitmap_equal(aqm,
+ (unsigned long *)crycb->apcb1.aqm, 256);
+ VM_EVENT(kvm, 3, "TEST CRYCB: aqm %016lx %016lx %016lx %016lx",
+ aqm[0], aqm[1], aqm[2], aqm[3]);
+ ret &= bitmap_equal(adm,
+ (unsigned long *)crycb->apcb1.adm, 256);
+ VM_EVENT(kvm, 3, "TEST CRYCB: adm %016lx %016lx %016lx %016lx",
+ adm[0], adm[1], adm[2], adm[3]);
+ break;
+ case CRYCB_FORMAT1:
+ case CRYCB_FORMAT0: /* Fall through both use APCB0 */
+ ret = bitmap_equal(apm, (unsigned long *)crycb->apcb1.apm, 64);
+ ret &= bitmap_equal(aqm, (unsigned long *)crycb->apcb1.aqm, 16);
+ ret &= bitmap_equal(adm, (unsigned long *)crycb->apcb1.adm, 16);

All of the above need to access crycb->apcb0

+ VM_EVENT(kvm, 3, "TEST CRYCB: apm %016lx aqm %04x adm %04x",
+ apm[0], *((unsigned short *)aqm),
+ *((unsigned short *)adm));
+ break;
+ default: /* Can not happen */
+ ret = 0;
+ break;
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_arch_crypto_test_masks);
+
void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
unsigned long *aqm, unsigned long *adm)
{
diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index f340a28c1d65..2a79d27d9730 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -42,12 +42,24 @@ MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids);
static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
{
- return 0;
+ struct ap_queue *apq = to_ap_queue(&apdev->device);
+ unsigned long apid = AP_QID_CARD(apq->qid);
+ unsigned long apqi = AP_QID_QUEUE(apq->qid);
+
+ mutex_lock(&matrix_dev->lock);
+ vfio_ap_mdev_probe_queue(apid, apqi);
+ mutex_unlock(&matrix_dev->lock);
}
static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
{
- /* Nothing to do yet */
+ struct ap_queue *apq = to_ap_queue(&apdev->device);
+ unsigned long apid = AP_QID_CARD(apq->qid);
+ unsigned long apqi = AP_QID_QUEUE(apq->qid);
+
+ mutex_lock(&matrix_dev->lock);
+ vfio_ap_mdev_remove_queue(apid, apqi);
+ mutex_unlock(&matrix_dev->lock);
}
static void vfio_ap_matrix_dev_release(struct device *dev)
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index ade2c150fe6b..8a70707bf870 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -683,8 +683,8 @@ static void vfio_ap_mdev_wait_for_qempty(unsigned long apid, unsigned long apqi)
msleep(20);
break;
default:
- pr_warn("%s: tapq err %02x: 0x%04x may not be empty\n",
- __func__, status.response_code, q->apqn);
+ pr_warn("%s: tapq err %02x: %02lx%04lx may not be empty\n",
+ __func__, status.response_code, apid, apqi);
return;
}
} while (--retry);
@@ -840,3 +840,66 @@ void vfio_ap_mdev_unregister(void)
{
mdev_unregister_device(&matrix_dev->device);
}
+
+static struct ap_matrix_mdev *vfio_ap_mdev_find_matrix_mdev(unsigned long apid,
+ unsigned long apqi)
+{
+ struct ap_matrix_mdev *matrix_mdev;
+
+ list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) {
+ if (test_bit_inv(apid, matrix_mdev->matrix.apm) &&
+ test_bit_inv(apqi, matrix_mdev->matrix.aqm))
+ return matrix_mdev;
+ }
+
+ return NULL;
+}
+
+void vfio_ap_mdev_remove_queue(unsigned long apid, unsigned long apqi)
+{
+ struct ap_matrix_mdev *matrix_mdev;
+
+ matrix_mdev = vfio_ap_mdev_find_matrix_mdev(apid, apqi);
+
+ /*
+ * If the queue is assigned to the mdev device and the mdev device
+ * is in use by a guest
+ */
+ if (matrix_mdev && matrix_mdev->kvm) {
+ /*
+ * If the queue is plugged into the guest, unplug the adapter
+ * but keep the adapter assigned to the mdev device
+ */
+ if (!kvm_arch_crypto_test_masks(matrix_mdev->kvm,
+ matrix_mdev->matrix.apm,
+ matrix_mdev->matrix.aqm,
+ matrix_mdev->matrix.adm)) {
+ clear_bit_inv(apid, matrix_mdev->matrix.apm);
+ vfio_ap_mdev_update_crycb(matrix_mdev);
+ set_bit_inv(apid, matrix_mdev->matrix.apm);
+ }
+ }
+
+ vfio_ap_mdev_reset_queue(apid, apqi);
+}
+
+void vfio_ap_mdev_probe_queue(unsigned long apid, unsigned long apqi)
+{
+ struct ap_matrix_mdev *matrix_mdev;
+
+ matrix_mdev = vfio_ap_mdev_find_matrix_mdev(apid, apqi);
+
+ /*
+ * If the queue is assigned to the mdev device and the mdev device
+ * is in use by a guest
+ */
+ if (matrix_mdev && matrix_mdev->kvm) {
+ /* If the queue is not plugged into the guest, plug it in */
+ if (!kvm_arch_crypto_test_masks(matrix_mdev->kvm,
+ matrix_mdev->matrix.apm,
+ matrix_mdev->matrix.aqm,
+ matrix_mdev->matrix.adm)) {
+ vfio_ap_mdev_update_crycb(matrix_mdev);
+ }
+ }
+}
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 76b7f98e47e9..acdd5bfabaaf 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -85,5 +85,7 @@ struct ap_matrix_mdev {
extern int vfio_ap_mdev_register(void);
extern void vfio_ap_mdev_unregister(void);
+void vfio_ap_mdev_remove_queue(unsigned long apid, unsigned long apqi);
+void vfio_ap_mdev_probe_queue(unsigned long apid, unsigned long apqi);
#endif /* _VFIO_AP_PRIVATE_H_ */