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Message-ID: <20201126154538.2004f0a5.pasic@linux.ibm.com>
Date: Thu, 26 Nov 2020 15:45:38 +0100
From: Halil Pasic <pasic@...ux.ibm.com>
To: Tony Krowiak <akrowiak@...ux.ibm.com>
Cc: linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org, freude@...ux.ibm.com, borntraeger@...ibm.com,
cohuck@...hat.com, mjrosato@...ux.ibm.com,
alex.williamson@...hat.com, kwankhede@...dia.com,
fiuczy@...ux.ibm.com, frankja@...ux.ibm.com, david@...hat.com,
hca@...ux.ibm.com, gor@...ux.ibm.com
Subject: Re: [PATCH v12 05/17] s390/vfio-ap: manage link between queue
struct and matrix mdev
On Tue, 24 Nov 2020 16:40:04 -0500
Tony Krowiak <akrowiak@...ux.ibm.com> wrote:
> Let's create links between each queue device bound to the vfio_ap device
> driver and the matrix mdev to which the queue is assigned. The idea is to
> facilitate efficient retrieval of the objects representing the queue
> devices and matrix mdevs as well as to verify that a queue assigned to
> a matrix mdev is bound to the driver.
>
> The links will be created as follows:
>
> * When the queue device is probed, if its APQN is assigned to a matrix
> mdev, the structures representing the queue device and the matrix mdev
> will be linked.
>
> * When an adapter or domain is assigned to a matrix mdev, for each new
> APQN assigned that references a queue device bound to the vfio_ap
> device driver, the structures representing the queue device and the
> matrix mdev will be linked.
>
> The links will be removed as follows:
>
> * When the queue device is removed, if its APQN is assigned to a matrix
> mdev, the structures representing the queue device and the matrix mdev
> will be unlinked.
>
> * When an adapter or domain is unassigned from a matrix mdev, for each
> APQN unassigned that references a queue device bound to the vfio_ap
> device driver, the structures representing the queue device and the
> matrix mdev will be unlinked.
>
> Signed-off-by: Tony Krowiak <akrowiak@...ux.ibm.com>
Actually some aspects of this look much better than last time,
but I'm afraid there one new issue that must be corrected -- see below.
> ---
> drivers/s390/crypto/vfio_ap_ops.c | 161 +++++++++++++++++++++++---
> drivers/s390/crypto/vfio_ap_private.h | 3 +
> 2 files changed, 146 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index dc699fd54505..07caf871943c 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -28,7 +28,6 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
>
> /**
> * vfio_ap_get_queue: Retrieve a queue with a specific APQN.
> - * @matrix_mdev: the associated mediated matrix
> * @apqn: The queue APQN
> *
> * Retrieve a queue with a specific APQN from the AP queue devices attached to
> @@ -36,32 +35,36 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
> *
> * Returns the pointer to the vfio_ap_queue with the specified APQN, or NULL.
> */
> -static struct vfio_ap_queue *vfio_ap_get_queue(
> - struct ap_matrix_mdev *matrix_mdev,
> - int apqn)
> +static struct vfio_ap_queue *vfio_ap_get_queue(int apqn)
> {
> struct ap_queue *queue;
> struct vfio_ap_queue *q = NULL;
>
> - if (!test_bit_inv(AP_QID_CARD(apqn), matrix_mdev->matrix.apm))
> - return NULL;
> - if (!test_bit_inv(AP_QID_QUEUE(apqn), matrix_mdev->matrix.aqm))
> - return NULL;
> -
> queue = ap_get_qdev(apqn);
> if (!queue)
> return NULL;
>
> put_device(&queue->ap_dev.device);
>
> - if (queue->ap_dev.device.driver == &matrix_dev->vfio_ap_drv->driver) {
> + if (queue->ap_dev.device.driver == &matrix_dev->vfio_ap_drv->driver)
> q = dev_get_drvdata(&queue->ap_dev.device);
> - q->matrix_mdev = matrix_mdev;
> - }
>
> return q;
> }
>
> +static struct vfio_ap_queue *
> +vfio_ap_mdev_get_queue(struct ap_matrix_mdev *matrix_mdev, unsigned long apqn)
> +{
> + struct vfio_ap_queue *q;
> +
> + hash_for_each_possible(matrix_mdev->qtable, q, mdev_qnode, apqn) {
> + if (q && (q->apqn == apqn))
> + return q;
> + }
> +
> + return NULL;
> +}
> +
> /**
> * vfio_ap_wait_for_irqclear
> * @apqn: The AP Queue number
> @@ -172,7 +175,6 @@ static struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q)
> status.response_code);
> end_free:
> vfio_ap_free_aqic_resources(q);
> - q->matrix_mdev = NULL;
> return status;
> }
>
> @@ -288,7 +290,7 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
> matrix_mdev = container_of(vcpu->kvm->arch.crypto.pqap_hook,
> struct ap_matrix_mdev, pqap_hook);
>
> - q = vfio_ap_get_queue(matrix_mdev, apqn);
> + q = vfio_ap_mdev_get_queue(matrix_mdev, apqn);
> if (!q)
> goto out_unlock;
>
> @@ -331,6 +333,7 @@ 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);
> + hash_init(matrix_mdev->qtable);
> mdev_set_drvdata(mdev, matrix_mdev);
> matrix_mdev->pqap_hook.hook = handle_pqap;
> matrix_mdev->pqap_hook.owner = THIS_MODULE;
> @@ -559,6 +562,87 @@ static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev)
> return 0;
> }
>
> +enum qlink_action {
> + LINK_APID,
> + LINK_APQI,
> + UNLINK_APID,
> + UNLINK_APQI,
> +};
> +
> +static void vfio_ap_mdev_link_queue(struct ap_matrix_mdev *matrix_mdev,
> + unsigned long apid, unsigned long apqi)
> +{
> + struct vfio_ap_queue *q;
> +
> + q = vfio_ap_get_queue(AP_MKQID(apid, apqi));
> + if (q) {
> + q->matrix_mdev = matrix_mdev;
> + hash_add(matrix_mdev->qtable,
> + &q->mdev_qnode, q->apqn);
> + }
> +}
> +
> +static void vfio_ap_mdev_unlink_queue(unsigned long apid, unsigned long apqi)
> +{
> + struct vfio_ap_queue *q;
> +
> + q = vfio_ap_get_queue(AP_MKQID(apid, apqi));
> + if (q) {
> + q->matrix_mdev = NULL;
> + hash_del(&q->mdev_qnode);
> + }
> +}
I would do
+static void vfio_ap_mdev_unlink_queue(struct vfio_ap_queue *q)
+{
+ if (!q)
+ return;
+ q->matrix_mdev = NULL;
+ hash_del(&q->mdev_qnode);
+}
+
+static void vfio_ap_mdev_unlink_queue_by_id(unsigned long apid, unsigned long apqi)
+{
+ struct vfio_ap_queue *q = vfio_ap_get_queue(AP_MKQID(apid, apqi));
+
+ vfio_ap_mdev_unlink_queue(q);
+}
> +
> +/**
> + * vfio_ap_mdev_manage_qlinks
> + *
> + * @matrix_mdev: The matrix mdev to link.
> + * @action: The action to take on @qlink_id.
> + * @qlink_id: The APID or APQI of the queues to link.
> + *
> + * Sets or clears the links between the queues with the specified @qlink_id
> + * and the @matrix_mdev:
> + * @action == LINK_APID: Set the links between the @matrix_mdev and the
> + * queues with the specified @qlink_id (APID)
> + * @action == LINK_APQI: Set the links between the @matrix_mdev and the
> + * queues with the specified @qlink_id (APQI)
> + * @action == UNLINK_APID: Clear the links between the @matrix_mdev and the
> + * queues with the specified @qlink_id (APID)
> + * @action == UNLINK_APQI: Clear the links between the @matrix_mdev and the
> + * queues with the specified @qlink_id (APQI)
> + */
> +static void vfio_ap_mdev_manage_qlinks(struct ap_matrix_mdev *matrix_mdev,
> + enum qlink_action action,
> + unsigned long qlink_id)
> +{
> + unsigned long id;
> +
> + switch (action) {
> + case LINK_APID:
> + for_each_set_bit_inv(id, matrix_mdev->matrix.aqm,
> + matrix_mdev->matrix.aqm_max + 1)
> + vfio_ap_mdev_link_queue(matrix_mdev, qlink_id, id);
> + break;
> + case UNLINK_APID:
> + for_each_set_bit_inv(id, matrix_mdev->matrix.aqm,
> + matrix_mdev->matrix.aqm_max + 1)
> + vfio_ap_mdev_unlink_queue(qlink_id, id);
> + break;
> + case LINK_APQI:
> + for_each_set_bit_inv(id, matrix_mdev->matrix.apm,
> + matrix_mdev->matrix.apm_max + 1)
> + vfio_ap_mdev_link_queue(matrix_mdev, id, qlink_id);
> + break;
> + case UNLINK_APQI:
> + for_each_set_bit_inv(id, matrix_mdev->matrix.apm,
> + matrix_mdev->matrix.apm_max + 1)
> + vfio_ap_mdev_link_queue(matrix_mdev, id, qlink_id);
> + break;
> + default:
> + WARN_ON_ONCE(1);
> + }
> +}
> +
> /**
> * assign_adapter_store
> *
> @@ -628,6 +712,7 @@ static ssize_t assign_adapter_store(struct device *dev,
> if (ret)
> goto share_err;
>
> + vfio_ap_mdev_manage_qlinks(matrix_mdev, LINK_APID, apid);
> ret = count;
> goto done;
>
> @@ -679,6 +764,7 @@ static ssize_t unassign_adapter_store(struct device *dev,
>
> mutex_lock(&matrix_dev->lock);
> clear_bit_inv((unsigned long)apid, matrix_mdev->matrix.apm);
> + vfio_ap_mdev_manage_qlinks(matrix_mdev, UNLINK_APID, apid);
> mutex_unlock(&matrix_dev->lock);
>
> return count;
> @@ -769,6 +855,7 @@ static ssize_t assign_domain_store(struct device *dev,
> if (ret)
> goto share_err;
>
> + vfio_ap_mdev_manage_qlinks(matrix_mdev, LINK_APQI, apqi);
> ret = count;
> goto done;
>
> @@ -821,6 +908,7 @@ static ssize_t unassign_domain_store(struct device *dev,
>
> mutex_lock(&matrix_dev->lock);
> clear_bit_inv((unsigned long)apqi, matrix_mdev->matrix.aqm);
> + vfio_ap_mdev_manage_qlinks(matrix_mdev, UNLINK_APQI, apqi);
> mutex_unlock(&matrix_dev->lock);
>
> return count;
> @@ -1155,6 +1243,11 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
> matrix_mdev->matrix.apm_max + 1) {
> for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
> matrix_mdev->matrix.aqm_max + 1) {
> + q = vfio_ap_mdev_get_queue(matrix_mdev,
> + AP_MKQID(apid, apqi));
> + if (!q)
> + continue;
> +
> ret = vfio_ap_mdev_reset_queue(apid, apqi, 1);
> /*
> * Regardless whether a queue turns out to be busy, or
> @@ -1164,9 +1257,7 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
> if (ret)
> rc = ret;
>
> - q = vfio_ap_get_queue(matrix_mdev, AP_MKQID(apid, apqi);
> - if (q)
> - vfio_ap_free_aqic_resources(q);
> + vfio_ap_free_aqic_resources(q);
> }
> }
>
> @@ -1292,6 +1383,29 @@ void vfio_ap_mdev_unregister(void)
> mdev_unregister_device(&matrix_dev->device);
> }
>
> +/*
> + * vfio_ap_queue_link_mdev
> + *
> + * @q: The queue to link with the matrix mdev.
> + *
> + * Links @q with the matrix mdev to which the queue's APQN is assigned.
> + */
> +static void vfio_ap_queue_link_mdev(struct vfio_ap_queue *q)
> +{
> + unsigned long apid = AP_QID_CARD(q->apqn);
> + unsigned long apqi = AP_QID_QUEUE(q->apqn);
> + 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)) {
> + q->matrix_mdev = matrix_mdev;
> + hash_add(matrix_mdev->qtable, &q->mdev_qnode, q->apqn);
> + break;
> + }
> + }
> +}
> +
> /**
> * vfio_ap_mdev_probe_queue:
> *
> @@ -1305,9 +1419,13 @@ int vfio_ap_mdev_probe_queue(struct ap_device *apdev)
> q = kzalloc(sizeof(*q), GFP_KERNEL);
> if (!q)
> return -ENOMEM;
> + mutex_lock(&matrix_dev->lock);
> dev_set_drvdata(&apdev->device, q);
> q->apqn = to_ap_queue(&apdev->device)->qid;
> q->saved_isc = VFIO_AP_ISC_INVALID;
> + vfio_ap_queue_link_mdev(q);
> + mutex_unlock(&matrix_dev->lock);
> +
> return 0;
> }
>
> @@ -1328,7 +1446,14 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
> apid = AP_QID_CARD(q->apqn);
> apqi = AP_QID_QUEUE(q->apqn);
> vfio_ap_mdev_reset_queue(apid, apqi, 1);
Does it make sense to reset if !q->matrix_dev?
> - vfio_ap_irq_disable(q);
> + if (q->matrix_mdev) {
> + if (q->matrix_mdev->kvm) {
> + vfio_ap_free_aqic_resources(q);
Again this belongs to the previous patch.
> + kvm_put_kvm(q->matrix_mdev->kvm);
This kvm_put_kvm() makes no sense to me! Please explain. Where
is the corresponding kvm_get_kvm()?
> + }
> + hash_del(&q->mdev_qnode);
> + q->matrix_mdev = NULL;
This shouuld be an unlink_queue(q).
> + }
> kfree(q);
> mutex_unlock(&matrix_dev->lock);
> }
> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
> index d9003de4fbad..4e5cc72fc0db 100644
> --- a/drivers/s390/crypto/vfio_ap_private.h
> +++ b/drivers/s390/crypto/vfio_ap_private.h
> @@ -18,6 +18,7 @@
> #include <linux/delay.h>
> #include <linux/mutex.h>
> #include <linux/kvm_host.h>
> +#include <linux/hashtable.h>
>
> #include "ap_bus.h"
>
> @@ -86,6 +87,7 @@ struct ap_matrix_mdev {
> struct kvm *kvm;
> struct kvm_s390_module_hook pqap_hook;
> struct mdev_device *mdev;
> + DECLARE_HASHTABLE(qtable, 8);
> };
>
> extern int vfio_ap_mdev_register(void);
> @@ -97,6 +99,7 @@ struct vfio_ap_queue {
> int apqn;
> #define VFIO_AP_ISC_INVALID 0xff
> unsigned char saved_isc;
> + struct hlist_node mdev_qnode;
> };
>
> int vfio_ap_mdev_probe_queue(struct ap_device *queue);
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