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Date: Mon, 6 May 2019 16:39:01 -0400
From: Tony Krowiak <akrowiak@...ux.ibm.com>
To: pmorel@...ux.ibm.com, linux-s390@...r.kernel.org,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc: freude@...ux.ibm.com, borntraeger@...ibm.com, cohuck@...hat.com,
frankja@...ux.ibm.com, david@...hat.com, schwidefsky@...ibm.com,
heiko.carstens@...ibm.com, pasic@...ux.ibm.com,
alex.williamson@...hat.com, kwankhede@...dia.com
Subject: Re: [PATCH v2 5/7] s390: vfio-ap: allow hot plug/unplug of AP
resources using mdev device
On 5/6/19 6:42 AM, Pierre Morel wrote:
> On 03/05/2019 23:14, Tony Krowiak wrote:
>> Let's allow AP resources to be assigned to or unassigned from an AP
>> matrix
>> mdev device while it is in use by a guest. If a guest is using the mdev
>> device while assignment is taking place, the guest will be granted access
>> to the resource as long as the guest will not be given access to an AP
>> queue device that is not bound to the vfio_ap device driver. If a
>> guest is
>> using the mdev device while unassignment is taking place, access to the
>> resource will be taken from the guest.
>>
>> Signed-off-by: Tony Krowiak <akrowiak@...ux.ibm.com>
>> ---
>> drivers/s390/crypto/vfio_ap_ops.c | 116
>> ++++++++++++++++++++++++++++----------
>> 1 file changed, 86 insertions(+), 30 deletions(-)
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
>> b/drivers/s390/crypto/vfio_ap_ops.c
>> index ea24caf17a16..ede45184eb67 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -226,6 +226,8 @@ static struct device
>> *vfio_ap_get_queue_dev(unsigned long apid,
>> &apqn, match_apqn);
>> }
>> +
>> +
>
> two white lines
I will fix it.
>
>> static int vfio_ap_mdev_validate_masks(unsigned long *apm, unsigned
>> long *aqm)
>> {
>> int ret;
>> @@ -237,6 +239,26 @@ static int vfio_ap_mdev_validate_masks(unsigned
>> long *apm, unsigned long *aqm)
>> return vfio_ap_mdev_verify_no_sharing(apm, aqm);
>> }
>> +static bool vfio_ap_queues_on_drv(unsigned long *apm, unsigned long
>> *aqm)
>> +{
>> + unsigned long apid, apqi, apqn;
>> + struct device *dev;
>> +
>> + for_each_set_bit_inv(apid, apm, AP_DEVICES) {
>> + for_each_set_bit_inv(apqi, aqm, AP_DOMAINS) {
>> + apqn = AP_MKQID(apid, apqi);
>
> You do not use apqn in the function.
Must be a remnant of another iteration. I'll remove it.
>
>> +
>> + dev = vfio_ap_get_queue_dev(apid, apqi);
>> + if (!dev)
>> + return false;
>> +
>> + put_device(dev);
>> + }
>> + }
>> +
>> + return true;
>> +}
>> +
>> /**
>> * assign_adapter_store
>> *
>> @@ -247,7 +269,10 @@ static int vfio_ap_mdev_validate_masks(unsigned
>> long *apm, unsigned long *aqm)
>> * @count: the number of bytes in @buf
>> *
>> * Parses the APID from @buf and sets the corresponding bit in the
>> mediated
>> - * matrix device's APM.
>> + * matrix device's APM. If a guest is using the mediated matrix
>> device and each
>> + * new APQN formed as a result of the assignment identifies an AP
>> queue device
>> + * that is bound to the vfio_ap device driver, the guest will be
>> granted access
>> + * to the adapter with the specified APID.
>> *
>> * Returns the number of bytes processed if the APID is valid;
>> otherwise,
>> * returns one of the following errors:
>> @@ -279,10 +304,6 @@ 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;
>> @@ -300,6 +321,14 @@ static ssize_t assign_adapter_store(struct device
>> *dev,
>> return ret;
>> }
>> set_bit_inv(apid, matrix_mdev->matrix.apm);
>> +
>> + if (matrix_mdev->shadow_crycb) {
>> + if (vfio_ap_queues_on_drv(apm,
>> + matrix_mdev->shadow_crycb->aqm)) {
>> + set_bit_inv(apid, matrix_mdev->shadow_crycb->apm);
>> + vfio_ap_mdev_update_crycb(matrix_mdev);
>> + }
>> + }
>> mutex_unlock(&matrix_dev->lock);
>> return count;
>> @@ -315,7 +344,9 @@ static DEVICE_ATTR_WO(assign_adapter);
>> * @count: the number of bytes in @buf
>> *
>> * Parses the APID from @buf and clears the corresponding bit in the
>> mediated
>> - * matrix device's APM.
>> + * matrix device's APM. If a guest is using the mediated matrix
>> device and has
>> + * access to the AP adapter with the specified APID, access to the
>> adapter will
>> + * be taken from the guest.
>> *
>> * Returns the number of bytes processed if the APID is valid;
>> otherwise,
>> * returns one of the following errors:
>> @@ -332,10 +363,6 @@ 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;
>> @@ -345,6 +372,13 @@ static ssize_t unassign_adapter_store(struct
>> device *dev,
>> mutex_lock(&matrix_dev->lock);
>> clear_bit_inv((unsigned long)apid, matrix_mdev->matrix.apm);
>> +
>> + if (matrix_mdev->shadow_crycb) {
>> + if (test_bit_inv(apid, matrix_mdev->shadow_crycb->apm)) {
>> + clear_bit_inv(apid, matrix_mdev->shadow_crycb->apm);
>> + vfio_ap_mdev_update_crycb(matrix_mdev);
>> + }
>> + }
>> mutex_unlock(&matrix_dev->lock);
>> return count;
>> @@ -361,7 +395,10 @@ static DEVICE_ATTR_WO(unassign_adapter);
>> * @count: the number of bytes in @buf
>> *
>> * Parses the APQI from @buf and sets the corresponding bit in the
>> mediated
>> - * matrix device's AQM.
>> + * matrix device's AQM. If a guest is using the mediated matrix
>> device and each
>> + * new APQN formed as a result of the assignment identifies an AP
>> queue device
>> + * that is bound to the vfio_ap device driver, the guest will be
>> given access
>> + * to the AP queue(s) with the specified APQI.
>> *
>> * Returns the number of bytes processed if the APQI is valid;
>> otherwise returns
>> * one of the following errors:
>> @@ -394,10 +431,6 @@ 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;
>> @@ -414,6 +447,14 @@ static ssize_t assign_domain_store(struct device
>> *dev,
>> return ret;
>> }
>> set_bit_inv(apqi, matrix_mdev->matrix.aqm);
>> +
>> + if (matrix_mdev->shadow_crycb) {
>> + if (vfio_ap_queues_on_drv(matrix_mdev->shadow_crycb->apm,
>> + aqm)) {
>> + set_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm);
>> + vfio_ap_mdev_update_crycb(matrix_mdev);
>> + }
>> + }
>> mutex_unlock(&matrix_dev->lock);
>> return count;
>> @@ -431,7 +472,9 @@ static DEVICE_ATTR_WO(assign_domain);
>> * @count: the number of bytes in @buf
>> *
>> * Parses the APQI from @buf and clears the corresponding bit in the
>> - * mediated matrix device's AQM.
>> + * mediated matrix device's AQM. If a guest is using the mediated
>> matrix device
>> + * and has access to queue(s) with the specified domain APQI, access to
>> + * the queue(s) will be taken away from the guest.
>> *
>> * Returns the number of bytes processed if the APQI is valid;
>> otherwise,
>> * returns one of the following errors:
>> @@ -447,10 +490,6 @@ 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;
>> @@ -460,6 +499,13 @@ static ssize_t unassign_domain_store(struct
>> device *dev,
>> mutex_lock(&matrix_dev->lock);
>> clear_bit_inv((unsigned long)apqi, matrix_mdev->matrix.aqm);
>> +
>> + if (matrix_mdev->shadow_crycb) {
>> + if (test_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm)) {
>> + clear_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm);
>> + vfio_ap_mdev_update_crycb(matrix_mdev);
>> + }
>> + }
>> mutex_unlock(&matrix_dev->lock);
>> return count;
>> @@ -475,7 +521,9 @@ static DEVICE_ATTR_WO(unassign_domain);
>> * @count: the number of bytes in @buf
>> *
>> * Parses the domain ID from @buf and sets the corresponding bit in
>> the mediated
>> - * matrix device's ADM.
>> + * matrix device's ADM. If a guest is using the mediated matrix
>> device and the
>> + * guest does not have access to the control domain with the
>> specified ID, the
>> + * guest will be granted access to it.
>> *
>> * Returns the number of bytes processed if the domain ID is valid;
>> otherwise,
>> * returns one of the following errors:
>> @@ -491,10 +539,6 @@ 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;
>> @@ -504,6 +548,13 @@ static ssize_t assign_control_domain_store(struct
>> device *dev,
>> mutex_lock(&matrix_dev->lock);
>> set_bit_inv(id, matrix_mdev->matrix.adm);
>> +
>> + if (matrix_mdev->shadow_crycb) {
>> + if (!test_bit_inv(id, matrix_mdev->shadow_crycb->adm)) {
>> + set_bit_inv(id, matrix_mdev->shadow_crycb->adm);
>> + vfio_ap_mdev_update_crycb(matrix_mdev);
>> + }
>> + }
>> mutex_unlock(&matrix_dev->lock);
>> return count;
>> @@ -519,7 +570,9 @@ static DEVICE_ATTR_WO(assign_control_domain);
>> * @count: the number of bytes in @buf
>> *
>> * Parses the domain ID from @buf and clears the corresponding bit
>> in the
>> - * mediated matrix device's ADM.
>> + * mediated matrix device's ADM. If a guest is using the mediated
>> matrix device
>> + * and has access to control domain with the specified domain ID,
>> access to
>> + * the control domain will be taken from the guest.
>> *
>> * Returns the number of bytes processed if the domain ID is valid;
>> otherwise,
>> * returns one of the following errors:
>> @@ -536,10 +589,6 @@ 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;
>> @@ -548,6 +597,13 @@ static ssize_t
>> unassign_control_domain_store(struct device *dev,
>> mutex_lock(&matrix_dev->lock);
>> clear_bit_inv(domid, matrix_mdev->matrix.adm);
>> +
>> + if (matrix_mdev->shadow_crycb) {
>> + if (test_bit_inv(domid, matrix_mdev->shadow_crycb->adm)) {
>> + clear_bit_inv(domid, matrix_mdev->shadow_crycb->adm);
>> + vfio_ap_mdev_update_crycb(matrix_mdev);
>> + }
>> + }
>> mutex_unlock(&matrix_dev->lock);
>> return count;
>>
>
> beside the two NITs, look good to me.
> Still need to test.
>
>
>
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