Re: [PATCH v10 13/16] s390/vfio-ap: handle host AP config change notification

Tony Krowiak
2020-10-12T20:53:20Z

On 9/27/20 9:38 PM, Halil Pasic wrote:
> On Fri, 21 Aug 2020 15:56:13 -0400
> Tony Krowiak <akrowiak@linux.ibm.com> wrote:
>
>> Implements the driver callback invoked by the AP bus when the host
>> AP configuration has changed. Since this callback is invoked prior to
>> unbinding a device from its device driver, the vfio_ap driver will
>> respond by unplugging the AP adapters, domains and control domains
>> removed from the host's AP configuration from the guests using them.
>>
>> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
>> Reported-by: kernel test robot <lkp@intel.com>
> Looks reasonable, but shouldn't vfio_ap_mdev_remove_queue() already
> have code that kicks the queue from the shadow at this stage?
>
> I mean if the removal is for a reason different that host config change,
> we wont update the guest_matrix or?
>
>> ---
>> drivers/s390/crypto/vfio_ap_drv.c | 5 +-
>> drivers/s390/crypto/vfio_ap_ops.c | 147 ++++++++++++++++++++++++--
>> drivers/s390/crypto/vfio_ap_private.h | 7 +-
>> 3 files changed, 146 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
>> index aae5b3d8e3fa..ea0a7603e886 100644
>> --- a/drivers/s390/crypto/vfio_ap_drv.c
>> +++ b/drivers/s390/crypto/vfio_ap_drv.c
>> @@ -115,9 +115,11 @@ static int vfio_ap_matrix_dev_create(void)
>>
>> /* Fill in config info via PQAP(QCI), if available */
>> if (test_facility(12)) {
>> - ret = ap_qci(&matrix_dev->info);
>> + ret = ap_qci(&matrix_dev->config_info);
>> if (ret)
>> goto matrix_alloc_err;
>> + memcpy(&matrix_dev->config_info_prev, &matrix_dev->config_info,
>> + sizeof(struct ap_config_info));
>> }
>>
>> mutex_init(&matrix_dev->lock);
>> @@ -177,6 +179,7 @@ static int __init vfio_ap_init(void)
>> vfio_ap_drv.remove = vfio_ap_queue_dev_remove;
>> vfio_ap_drv.in_use = vfio_ap_mdev_resource_in_use;
>> vfio_ap_drv.ids = ap_queue_ids;
>> + vfio_ap_drv.on_config_changed = vfio_ap_on_cfg_changed;
>>
>> ret = ap_driver_register(&vfio_ap_drv, THIS_MODULE, VFIO_AP_DRV_NAME);
>> if (ret) {
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
>> index 2b01a8eb6ee7..e002d556abab 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -347,7 +347,9 @@ static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
>> }
>>
>> matrix_mdev->mdev = mdev;
>> - vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
>> + vfio_ap_matrix_init(&matrix_dev->config_info, &matrix_mdev->matrix);
>> + vfio_ap_matrix_init(&matrix_dev->config_info,
>> + &matrix_mdev->shadow_apcb);
>> hash_init(matrix_mdev->qtable);
>> mdev_set_drvdata(mdev, matrix_mdev);
>> matrix_mdev->pqap_hook.hook = handle_pqap;
>> @@ -526,8 +528,8 @@ static int vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev *matrix_mdev,
>> * If the APID is not assigned to the host AP configuration,
>> * we can not assign it to the guest's AP configuration
>> */
>> - if (!test_bit_inv(apid,
>> - (unsigned long *)matrix_dev->info.apm)) {
>> + if (!test_bit_inv(apid, (unsigned long *)
>> + matrix_dev->config_info.apm)) {
>> clear_bit_inv(apid, shadow_apcb->apm);
>> continue;
>> }
>> @@ -540,7 +542,7 @@ static int vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev *matrix_mdev,
>> * guest's AP configuration
>> */
>> if (!test_bit_inv(apqi, (unsigned long *)
>> - matrix_dev->info.aqm)) {
>> + matrix_dev->config_info.aqm)) {
>> clear_bit_inv(apqi, shadow_apcb->aqm);
>> continue;
>> }
>> @@ -594,7 +596,7 @@ static bool vfio_ap_mdev_config_shadow_apcb(struct ap_matrix_mdev *matrix_mdev)
>> int napm, naqm;
>> struct ap_matrix shadow_apcb;
>>
>> - vfio_ap_matrix_init(&matrix_dev->info, &shadow_apcb);
>> + vfio_ap_matrix_init(&matrix_dev->config_info, &shadow_apcb);
>> napm = bitmap_weight(matrix_mdev->matrix.apm, AP_DEVICES);
>> naqm = bitmap_weight(matrix_mdev->matrix.aqm, AP_DOMAINS);
>>
>> @@ -741,7 +743,7 @@ static bool vfio_ap_mdev_assign_apqis_4_apid(struct ap_matrix_mdev *matrix_mdev,
>>
>> for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS) {
>> if (!test_bit_inv(apqi,
>> - (unsigned long *) matrix_dev->info.aqm))
>> + (unsigned long *)matrix_dev->config_info.aqm))
>> clear_bit_inv(apqi, aqm);
>>
>> apqn = AP_MKQID(apid, apqi);
>> @@ -764,7 +766,7 @@ static bool vfio_ap_mdev_assign_guest_apid(struct ap_matrix_mdev *matrix_mdev,
>> unsigned long apqi, apqn;
>>
>> if (!vfio_ap_mdev_has_crycb(matrix_mdev) ||
>> - !test_bit_inv(apid, (unsigned long *)matrix_dev->info.apm))
>> + !test_bit_inv(apid, (unsigned long *)matrix_dev->config_info.apm))
>> return false;
>>
>> if (bitmap_empty(matrix_mdev->shadow_apcb.aqm, AP_DOMAINS))
>> @@ -931,8 +933,8 @@ static bool vfio_ap_mdev_assign_apids_4_apqi(struct ap_matrix_mdev *matrix_mdev,
>> bitmap_copy(apm, matrix_mdev->matrix.apm, AP_DEVICES);
>>
>> for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, AP_DEVICES) {
>> - if (!test_bit_inv(apid,
>> - (unsigned long *) matrix_dev->info.apm))
>> + if (!test_bit_inv(apid, (unsigned long *)
>> + matrix_dev->config_info.apm))
>> clear_bit_inv(apqi, apm);
>>
>> apqn = AP_MKQID(apid, apqi);
>> @@ -955,7 +957,7 @@ static bool vfio_ap_mdev_assign_guest_apqi(struct ap_matrix_mdev *matrix_mdev,
>> unsigned long apid, apqn;
>>
>> if (!vfio_ap_mdev_has_crycb(matrix_mdev) ||
>> - !test_bit_inv(apqi, (unsigned long *)matrix_dev->info.aqm))
>> + !test_bit_inv(apqi, (unsigned long *)matrix_dev->config_info.aqm))
>> return false;
>>
>> if (bitmap_empty(matrix_mdev->shadow_apcb.apm, AP_DEVICES))
>> @@ -1702,7 +1704,7 @@ int vfio_ap_mdev_probe_queue(struct ap_queue *queue)
>> void vfio_ap_mdev_remove_queue(struct ap_queue *queue)
>> {
>> struct vfio_ap_queue *q;
>> - int apid, apqi;
>> + unsigned long apid, apqi;
>>
> Unrelated?

Yes, I'll remove it.

>
>> mutex_lock(&matrix_dev->lock);
>> q = dev_get_drvdata(&queue->ap_dev.device);
>> @@ -1727,3 +1729,126 @@ bool vfio_ap_mdev_resource_in_use(unsigned long *apm, unsigned long *aqm)
>>
>> return in_use;
>> }
>> +
>> +/**
>> + * vfio_ap_mdev_unassign_apids
>> + *
>> + * @matrix_mdev: The matrix mediated device
>> + *
>> + * @aqm: A bitmap with 256 bits. Each bit in the map represents an APID from 0
>> + * to 255 (with the leftmost bit corresponding to APID 0).
>> + *
>> + * Unassigns each APID specified in @aqm that is assigned to the shadow CRYCB
>> + * of @matrix_mdev. Returns true if at least one APID is unassigned; otherwise,
>> + * returns false.
>> + */
>> +static bool vfio_ap_mdev_unassign_apids(struct ap_matrix_mdev *matrix_mdev,
>> + unsigned long *apm_unassign)
>> +{
>> + unsigned long apid;
>> + bool unassigned = false;
>> +
>> + /*
>> + * If the matrix mdev is not in use by a KVM guest, return indicating
>> + * that no APIDs have been unassigned.
>> + */
>> + if (!vfio_ap_mdev_has_crycb(matrix_mdev))
>> + return false;
>> +
>> + for_each_set_bit_inv(apid, apm_unassign, AP_DEVICES) {
>> + unassigned |= vfio_ap_mdev_unassign_guest_apid(matrix_mdev,
>> + apid);
>> + }
> I guess, we could accomplish the unassign with operations operating on
> full bitmaps (without looping over bits), but I have no strong opinion
> here.
>
>> +
>> + return unassigned;
>> +}
>> +
>> +/**
>> + * vfio_ap_mdev_unassign_apqis
>> + *
>> + * @matrix_mdev: The matrix mediated device
>> + *
>> + * @aqm: A bitmap with 256 bits. Each bit in the map represents an APQI from 0
>> + * to 255 (with the leftmost bit corresponding to APQI 0).
>> + *
>> + * Unassigns each APQI specified in @aqm that is assigned to the shadow CRYCB
>> + * of @matrix_mdev. Returns true if at least one APQI is unassigned; otherwise,
>> + * returns false.
>> + */
>> +static bool vfio_ap_mdev_unassign_apqis(struct ap_matrix_mdev *matrix_mdev,
>> + unsigned long *aqm_unassign)
>> +{
>> + unsigned long apqi;
>> + bool unassigned = false;
>> +
>> + /*
>> + * If the matrix mdev is not in use by a KVM guest, return indicating
>> + * that no APQIs have been unassigned.
>> + */
>> + if (!vfio_ap_mdev_has_crycb(matrix_mdev))
>> + return false;
>> +
>> + for_each_set_bit_inv(apqi, aqm_unassign, AP_DOMAINS) {
>> + unassigned |= vfio_ap_mdev_unassign_guest_apqi(matrix_mdev,
>> + apqi);
>> + }
>> +
>> + return unassigned;
>> +}
>> +
>> +void vfio_ap_on_cfg_changed(struct ap_config_info *new_config_info,
>> + struct ap_config_info *old_config_info)
>> +{
>> + bool unassigned;
>> + int ap_remove, aq_remove;
>> + struct ap_matrix_mdev *matrix_mdev;
>> + DECLARE_BITMAP(apm_unassign, AP_DEVICES);
>> + DECLARE_BITMAP(aqm_unassign, AP_DOMAINS);
>> +
>> + unsigned long *cur_apm, *cur_aqm, *prev_apm, *prev_aqm;
>> +
>> + if (matrix_dev->flags & AP_MATRIX_CFG_CHG) {
>> + WARN_ONCE(1, "AP host configuration change already reported");
>> + return;
>> + }
>> +
>> + memcpy(&matrix_dev->config_info, new_config_info,
>> + sizeof(struct ap_config_info));
>> + memcpy(&matrix_dev->config_info_prev, old_config_info,
>> + sizeof(struct ap_config_info));
>> +
>> + cur_apm = (unsigned long *)matrix_dev->config_info.apm;
>> + cur_aqm = (unsigned long *)matrix_dev->config_info.aqm;
>> + prev_apm = (unsigned long *)matrix_dev->config_info_prev.apm;
>> + prev_aqm = (unsigned long *)matrix_dev->config_info_prev.aqm;
>> +
>> + ap_remove = bitmap_andnot(apm_unassign, prev_apm, cur_apm, AP_DEVICES);
>> + aq_remove = bitmap_andnot(aqm_unassign, prev_aqm, cur_aqm, AP_DOMAINS);
>> +
>> + mutex_lock(&matrix_dev->lock);
>> + matrix_dev->flags |= AP_MATRIX_CFG_CHG;
>> +
>> + list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) {
>> + if (!vfio_ap_mdev_has_crycb(matrix_mdev))
>> + continue;
>> +
>> + unassigned = false;
>> +
>> + if (ap_remove)
>> + if (bitmap_intersects(matrix_mdev->shadow_apcb.apm,
>> + apm_unassign, AP_DEVICES))
>> + if (vfio_ap_mdev_unassign_apids(matrix_mdev,
>> + apm_unassign))
> This can be done with a single "if".
>
> if (A)
> if (B)
> if (C)
> D;
>
> should be equivalent with
> if (A && B && C)
> D;
> and your wouldn't end up that deep indentation. It is a style thing,
> so unless regulated by the official coding style, it is up to you :)
>
>
>> + unassigned = true;
>> + if (aq_remove)
>> + if (bitmap_intersects(matrix_mdev->shadow_apcb.aqm,
>> + aqm_unassign, AP_DOMAINS))
>> + if (vfio_ap_mdev_unassign_apqis(matrix_mdev,
>> + aqm_unassign))
>> + unassigned = true;
>> +
>> + if (unassigned)
>> + vfio_ap_mdev_commit_shadow_apcb(matrix_mdev);
>> + }
>> + mutex_unlock(&matrix_dev->lock);
>> +}
>> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
>> index 055bce6d45db..fc8629e28ad3 100644
>> --- a/drivers/s390/crypto/vfio_ap_private.h
>> +++ b/drivers/s390/crypto/vfio_ap_private.h
>> @@ -40,10 +40,13 @@
>> struct ap_matrix_dev {
>> struct device device;
>> atomic_t available_instances;
>> - struct ap_config_info info;
>> + struct ap_config_info config_info;
>> + struct ap_config_info config_info_prev;
>> struct list_head mdev_list;
>> struct mutex lock;
>> struct ap_driver *vfio_ap_drv;
>> + #define AP_MATRIX_CFG_CHG (1UL << 0)
>> + unsigned long flags;
>> };
>>
>> extern struct ap_matrix_dev *matrix_dev;
>> @@ -108,5 +111,7 @@ int vfio_ap_mdev_probe_queue(struct ap_queue *queue);
>> void vfio_ap_mdev_remove_queue(struct ap_queue *queue);
>>
>> bool vfio_ap_mdev_resource_in_use(unsigned long *apm, unsigned long *aqm);
>> +void vfio_ap_on_cfg_changed(struct ap_config_info *new_config_info,
>> + struct ap_config_info *old_config_info);
>>
>> #endif /* _VFIO_AP_PRIVATE_H_ */