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