[patch 15/20] genirq/msi: Provide new domain id allocation functions

Thomas Gleixner
2022-11-11T14:03:14Z

Provide two sorts of interfaces to handle the different use cases:

- msi_domain_alloc_irqs_range():

Handles a caller defined precise range

- msi_domain_alloc_irqs_all():

Allocates all interrupts associated to a domain by scanning the
allocated MSI descriptors

The latter is useful for the existing PCI/MSI support which does not have
range information available.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/msi.h | 18 ++---
kernel/irq/msi.c | 180 ++++++++++++++++++++++++++++++++++++++++------------
2 files changed, 149 insertions(+), 49 deletions(-)

--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -371,8 +371,8 @@ struct msi_domain_info;
* @get_hwirq, @msi_init and @msi_free are callbacks used by the underlying
* irqdomain.
*
- * @msi_check, @msi_prepare and @set_desc are callbacks used by
- * msi_domain_alloc/free_irqs().
+ * @msi_check, @msi_prepare and @set_desc are callbacks used by the
+ * msi_domain_alloc/free_irqs*() variants.
*
* @domain_alloc_irqs, @domain_free_irqs can be used to override the
* default allocation/free functions (__msi_domain_alloc/free_irqs). This
@@ -380,11 +380,6 @@ struct msi_domain_info;
* be wrapped into the regular irq domains concepts by mere mortals. This
* allows to universally use msi_domain_alloc/free_irqs without having to
* special case XEN all over the place.
- *
- * Contrary to other operations @domain_alloc_irqs and @domain_free_irqs
- * are set to the default implementation if NULL and even when
- * MSI_FLAG_USE_DEF_DOM_OPS is not set to avoid breaking existing users and
- * because these callbacks are obviously mandatory.
*/
struct msi_domain_ops {
irq_hw_number_t (*get_hwirq)(struct msi_domain_info *info,
@@ -484,14 +479,21 @@ int msi_domain_alloc_irqs_descs_locked(s
int nvec);
int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
int nvec);
+
void msi_domain_free_irqs_descs_locked(struct irq_domain *domain, struct device *dev);
void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev);

+int msi_domain_alloc_irqs_range_locked(struct device *dev, unsigned int domid,
+ unsigned int first, unsigned int last);
+int msi_domain_alloc_irqs_range(struct device *dev, unsigned int domid,
+ unsigned int first, unsigned int last);
+int msi_domain_alloc_irqs_all_locked(struct device *dev, unsigned int domid, int nirqs);
+
+
void msi_domain_free_irqs_range_locked(struct device *dev, unsigned int domid,
unsigned int first, unsigned int last);
void msi_domain_free_irqs_range(struct device *dev, unsigned int domid,
unsigned int first, unsigned int last);
-
void msi_domain_free_irqs_all_locked(struct device *dev, unsigned int domid);
void msi_domain_free_irqs_all(struct device *dev, unsigned int domid);

--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -24,11 +24,14 @@
* @domid: ID of the domain on which management operations should be done
* @first: First (hardware) slot index to operate on
* @last: Last (hardware) slot index to operate on
+ * @nirqs: The number of Linux interrupts to allocate. Can be larger
+ * than the range due to PCI/multi-MSI.
*/
struct msi_ctrl {
unsigned int domid;
unsigned int first;
unsigned int last;
+ unsigned int nirqs;
};

static inline int msi_sysfs_create_group(struct device *dev);
@@ -582,8 +585,6 @@ static inline int msi_sysfs_populate_des
static inline void msi_sysfs_remove_desc(struct device *dev, struct msi_desc *desc) { }
#endif /* !CONFIG_SYSFS */

-static int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, int nvec);
-
static struct irq_domain *msi_get_device_domain(struct device *dev, unsigned int domid)
{
struct irq_domain *domain;
@@ -597,7 +598,7 @@ static struct irq_domain *msi_get_device
if (!domain)
return NULL;

- if (WARN_ON_ONCE(irq_domain_is_msi_parent(domain)))
+ if (irq_domain_is_msi_parent(domain))
return NULL;

return domain;
@@ -761,7 +762,6 @@ static struct msi_domain_ops msi_domain_
.msi_init = msi_domain_ops_init,
.msi_prepare = msi_domain_ops_prepare,
.set_desc = msi_domain_ops_set_desc,
- .domain_alloc_irqs = __msi_domain_alloc_irqs,
};

static void msi_domain_update_dom_ops(struct msi_domain_info *info)
@@ -773,9 +773,6 @@ static void msi_domain_update_dom_ops(st
return;
}

- if (ops->domain_alloc_irqs == NULL)
- ops->domain_alloc_irqs = msi_domain_ops_default.domain_alloc_irqs;
-
if (!(info->flags & MSI_FLAG_USE_DEF_DOM_OPS))
return;

@@ -986,18 +983,19 @@ static int msi_init_virq(struct irq_doma
return 0;
}

-static int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
- int nvec)
+static int __msi_domain_alloc_irqs(struct device *dev, struct irq_domain *domain,
+ struct msi_ctrl *ctrl)
{
struct msi_domain_info *info = domain->host_data;
+ struct xarray *xa = &dev->msi.data->__store;
struct msi_domain_ops *ops = info->ops;
+ unsigned int vflags = 0, allocated = 0;
msi_alloc_info_t arg = { };
- unsigned int vflags = 0;
+ int i, ret, virq, base;
struct msi_desc *desc;
- int allocated = 0;
- int i, ret, virq;
+ unsigned long idx;

- ret = msi_domain_prepare_irqs(domain, dev, nvec, &arg);
+ ret = msi_domain_prepare_irqs(domain, dev, ctrl->nirqs, &arg);
if (ret)
return ret;

@@ -1023,7 +1021,16 @@ static int __msi_domain_alloc_irqs(struc
vflags |= VIRQ_NOMASK_QUIRK;
}

- msi_for_each_desc(desc, dev, MSI_DESC_NOTASSOCIATED) {
+ base = ctrl->domid * MSI_XA_DOMAIN_SIZE;
+
+ xa_for_each_range(xa, idx, desc, ctrl->first + base, ctrl->last + base) {
+ if (!msi_desc_match(desc, MSI_DESC_NOTASSOCIATED))
+ continue;
+
+ /* This should return -ECONFUSED... */
+ if (WARN_ON_ONCE(allocated >= ctrl->nirqs))
+ return -EINVAL;
+
ops->set_desc(&arg, desc);

virq = __irq_domain_alloc_irqs(domain, -1, desc->nvec_used,
@@ -1051,17 +1058,122 @@ static int __msi_domain_alloc_irqs(struc

static int msi_domain_alloc_simple_msi_descs(struct device *dev,
struct msi_domain_info *info,
- unsigned int num_descs)
+ struct msi_ctrl *ctrl)
+{
+ if (!(info->flags & MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS))
+ return 0;
+
+ return msi_domain_add_simple_msi_descs(dev, ctrl);
+}
+
+static int __msi_domain_alloc_locked(struct device *dev, struct msi_ctrl *ctrl)
+{
+ struct msi_domain_info *info;
+ struct msi_domain_ops *ops;
+ struct irq_domain *domain;
+ int ret;
+
+ if (!msi_ctrl_valid(dev, ctrl))
+ return -EINVAL;
+
+ domain = msi_get_device_domain(dev, ctrl->domid);
+ if (!domain)
+ return -ENODEV;
+
+ info = domain->host_data;
+
+ ret = msi_domain_alloc_simple_msi_descs(dev, info, ctrl);
+ if (ret)
+ return ret;
+
+ ops = info->ops;
+ if (ops->domain_alloc_irqs)
+ return ops->domain_alloc_irqs(domain, dev, ctrl->nirqs);
+
+ return __msi_domain_alloc_irqs(dev, domain, ctrl);
+}
+
+static int msi_domain_alloc_locked(struct device *dev, struct msi_ctrl *ctrl)
+{
+ int ret = __msi_domain_alloc_locked(dev, ctrl);
+
+ if (ret)
+ msi_domain_free_descs(dev, ctrl);
+ return ret;
+}
+
+/**
+ * msi_domain_alloc_irqs_range_locked - Allocate interrupts from a MSI interrupt domain
+ * @dev: Pointer to device struct of the device for which the interrupts
+ * are allocated
+ * @domid: Id of the interrupt domain to operate on
+ * @first: First index to allocate (inclusive)
+ * @last: Last index to allocate (inclusive)
+ *
+ * Must be invoked from within a msi_lock_descs() / msi_unlock_descs()
+ * pair. Use this for MSI irqdomains which implement their own descriptor
+ * allocation/free.
+ *
+ * Return: %0 on success or an error code.
+ */
+int msi_domain_alloc_irqs_range_locked(struct device *dev, unsigned int domid,
+ unsigned int first, unsigned int last)
{
struct msi_ctrl ctrl = {
- .domid = MSI_DEFAULT_DOMAIN,
- .last = num_descs - 1,
+ .domid = domid,
+ .first = first,
+ .last = last,
+ .nirqs = last + 1 - first,
};

- if (!(info->flags & MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS))
- return 0;
+ return msi_domain_alloc_locked(dev, &ctrl);
+}
+
+/**
+ * msi_domain_alloc_irqs_range - Allocate interrupts from a MSI interrupt domain
+ * @dev: Pointer to device struct of the device for which the interrupts
+ * are allocated
+ * @domid: Id of the interrupt domain to operate on
+ * @first: First index to allocate (inclusive)
+ * @last: Last index to allocate (inclusive)
+ *
+ * Return: %0 on success or an error code.
+ */
+int msi_domain_alloc_irqs_range(struct device *dev, unsigned int domid,
+ unsigned int first, unsigned int last)
+{
+ int ret;
+
+ msi_lock_descs(dev);
+ ret = msi_domain_alloc_irqs_range_locked(dev, domid, first, last);
+ msi_unlock_descs(dev);
+ return ret;
+}
+
+/**
+ * msi_domain_alloc_irqs_all_locked - Allocate all interrupts from a MSI interrupt domain
+ *
+ * @dev: Pointer to device struct of the device for which the interrupts
+ * are allocated
+ * @domid: Id of the interrupt domain to operate on
+ * @nirqs: The number of interrupts to allocate
+ *
+ * This function scans all MSI descriptors of the MSI domain and allocates interrupts
+ * for all unassigned ones. That function is to be used for MSI domain usage where
+ * the descriptor allocation is handled at the call site, e.g. PCI/MSI[X].
+ *
+ * Return: %0 on success or an error code.
+ */
+int msi_domain_alloc_irqs_all_locked(struct device *dev, unsigned int domid, int nirqs)
+{
+ struct msi_ctrl ctrl = {
+ .domid = domid,
+ .first = 0,
+ .last = MSI_MAX_INDEX,
+ .nirqs = nirqs,
+ };

- return msi_domain_add_simple_msi_descs(dev, &ctrl);
+ return msi_domain_alloc_locked(dev, &ctrl);
}

/**
@@ -1080,28 +1192,14 @@ static int msi_domain_alloc_simple_msi_d
int msi_domain_alloc_irqs_descs_locked(struct irq_domain *domain, struct device *dev,
int nvec)
{
- struct msi_domain_info *info = domain->host_data;
- struct msi_domain_ops *ops = info->ops;
- int ret;
-
- lockdep_assert_held(&dev->msi.data->mutex);
-
- if (WARN_ON_ONCE(irq_domain_is_msi_parent(domain))) {
- ret = -EINVAL;
- goto free;
- }
-
- /* Frees allocated descriptors in case of failure. */
- ret = msi_domain_alloc_simple_msi_descs(dev, info, nvec);
- if (ret)
- return ret;
+ struct msi_ctrl ctrl = {
+ .domid = MSI_DEFAULT_DOMAIN,
+ .first = 0,
+ .last = MSI_MAX_INDEX,
+ .nirqs = nvec,
+ };

- ret = ops->domain_alloc_irqs(domain, dev, nvec);
- if (!ret)
- return 0;
-free:
- msi_domain_free_irqs_descs_locked(domain, dev);
- return ret;
+ return msi_domain_alloc_locked(dev, &ctrl);
}

/**