[PATCH v2 4/8] s390: vfio-ap: allow hot plug/unplug of AP resources using mdev device

Tony Krowiak
2019-04-20T21:50:41Z

Let's allow adapters, domains and control domains to be assigned to or
unassigned from an AP matrix mdev device while it is in use by a guest.
When an adapter, domain or control domain is assigned to or unassigned
from an mdev device while a guest is using it, the guest's CRYCB will be
updated thus giving access to the resource assigned, or taking access away
from the resource unassigned for the guest.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_ops.c | 49 ++++++++++++---------------------------
1 file changed, 15 insertions(+), 34 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 221491a9ba95..091804317c5e 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -219,10 +219,6 @@ static ssize_t assign_adapter_store(struct device *dev,
struct mdev_device *mdev = mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

- /* If the guest is running, disallow assignment of adapter */
- if (matrix_mdev->kvm)
- return -EBUSY;
-
ret = kstrtoul(buf, 0, &apid);
if (ret)
return ret;
@@ -237,10 +233,6 @@ static ssize_t assign_adapter_store(struct device *dev,
*/
mutex_lock(&matrix_dev->lock);

- ret = vfio_ap_mdev_verify_queues_reserved_for_apid(matrix_mdev, apid);
- if (ret)
- goto done;
-
set_bit_inv(apid, matrix_mdev->matrix.apm);

ret = ap_apqn_in_matrix_owned_by_def_drv(matrix_mdev->matrix.apm,
@@ -258,6 +250,7 @@ static ssize_t assign_adapter_store(struct device *dev,
if (matrix_mdev->shadow_crycb)
set_bit_inv(apid, matrix_mdev->shadow_crycb->apm);

+ vfio_ap_mdev_update_crycb(matrix_mdev);
ret = count;
goto done;

@@ -296,10 +289,6 @@ static ssize_t unassign_adapter_store(struct device *dev,
struct mdev_device *mdev = mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

- /* If the guest is running, disallow un-assignment of adapter */
- if (matrix_mdev->kvm)
- return -EBUSY;
-
ret = kstrtoul(buf, 0, &apid);
if (ret)
return ret;
@@ -312,6 +301,8 @@ static ssize_t unassign_adapter_store(struct device *dev,

if (matrix_mdev->shadow_crycb)
clear_bit_inv(apid, matrix_mdev->shadow_crycb->apm);
+
+ vfio_ap_mdev_update_crycb(matrix_mdev);
mutex_unlock(&matrix_dev->lock);

return count;
@@ -360,10 +351,6 @@ static ssize_t assign_domain_store(struct device *dev,
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
unsigned long max_apqi = matrix_mdev->matrix.aqm_max;

- /* If the guest is running, disallow assignment of domain */
- if (matrix_mdev->kvm)
- return -EBUSY;
-
ret = kstrtoul(buf, 0, &apqi);
if (ret)
return ret;
@@ -384,15 +371,16 @@ static ssize_t assign_domain_store(struct device *dev,

ret = vfio_ap_mdev_verify_no_sharing(matrix_mdev);
if (ret)
- goto share_err;
+ goto error;

if (matrix_mdev->shadow_crycb)
set_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm);

+ vfio_ap_mdev_update_crycb(matrix_mdev);
ret = count;
goto done;

-share_err:
+error:
clear_bit_inv(apqi, matrix_mdev->matrix.aqm);
done:
mutex_unlock(&matrix_dev->lock);
@@ -428,10 +416,6 @@ static ssize_t unassign_domain_store(struct device *dev,
struct mdev_device *mdev = mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

- /* If the guest is running, disallow un-assignment of domain */
- if (matrix_mdev->kvm)
- return -EBUSY;
-
ret = kstrtoul(buf, 0, &apqi);
if (ret)
return ret;
@@ -445,6 +429,7 @@ static ssize_t unassign_domain_store(struct device *dev,
if (matrix_mdev->shadow_crycb)
clear_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm);

+ vfio_ap_mdev_update_crycb(matrix_mdev);
mutex_unlock(&matrix_dev->lock);

return count;
@@ -476,10 +461,6 @@ static ssize_t assign_control_domain_store(struct device *dev,
struct mdev_device *mdev = mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

- /* If the guest is running, disallow assignment of control domain */
- if (matrix_mdev->kvm)
- return -EBUSY;
-
ret = kstrtoul(buf, 0, &id);
if (ret)
return ret;
@@ -487,10 +468,12 @@ static ssize_t assign_control_domain_store(struct device *dev,
if (id > matrix_mdev->matrix.adm_max)
return -ENODEV;

- /* Set the bit in the ADM (bitmask) corresponding to the AP control
- * domain number (id). The bits in the mask, from most significant to
- * least significant, correspond to IDs 0 up to the one less than the
- * number of control domains that can be assigned.
+ /*
+ * Set the bits in the ADM (bitmask) corresponding to the AP control
+ * domain numbers in dommask. The bits in the mask, from left to right,
+ * correspond to IDs 0 up to the one less than the number of control
+ * domains that can be assigned.
+ *
*/
mutex_lock(&matrix_dev->lock);
set_bit_inv(id, matrix_mdev->matrix.adm);
@@ -498,6 +481,7 @@ static ssize_t assign_control_domain_store(struct device *dev,
if (matrix_mdev->shadow_crycb)
set_bit_inv(id, matrix_mdev->shadow_crycb->adm);

+ vfio_ap_mdev_update_crycb(matrix_mdev);
mutex_unlock(&matrix_dev->lock);

return count;
@@ -530,10 +514,6 @@ static ssize_t unassign_control_domain_store(struct device *dev,
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
unsigned long max_domid = matrix_mdev->matrix.adm_max;

- /* If the guest is running, disallow un-assignment of control domain */
- if (matrix_mdev->kvm)
- return -EBUSY;
-
ret = kstrtoul(buf, 0, &domid);
if (ret)
return ret;
@@ -546,6 +526,7 @@ static ssize_t unassign_control_domain_store(struct device *dev,
if (matrix_mdev->shadow_crycb)
clear_bit_inv(domid, matrix_mdev->shadow_crycb->adm);

+ vfio_ap_mdev_update_crycb(matrix_mdev);
mutex_unlock(&matrix_dev->lock);

return count;
--
2.7.4