This patch creates an irq map per VMD device msix vector (irq list), and
maps vmdirq nodes into the irq map. The goal is to be able to get a
reference for all vmd_irqs in the vmd_irq_list within a single page.
Each vmd_irq is tracked with the id allocator, and if the id allocation
fails (if many devices are connected), it will fall back to a normal
kzalloc.
Indexing/traversing will still be managed with list primitives, because
we still need the rcu protection.
Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
---
arch/x86/pci/vmd.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 59 insertions(+), 10 deletions(-)
diff --git a/arch/x86/pci/vmd.c b/arch/x86/pci/vmd.c
index aa8d74e..c25fb46 100644
--- a/arch/x86/pci/vmd.c
+++ b/arch/x86/pci/vmd.c
@@ -21,6 +21,7 @@
#include <linux/pci.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
+#include <linux/idr.h>
#include <asm/irqdomain.h>
#include <asm/device.h>
@@ -41,8 +42,9 @@ static DEFINE_RAW_SPINLOCK(list_lock);
* @node: list item for parent traversal.
* @rcu: RCU callback item for freeing.
* @irq: back pointer to parent.
- * @enabled: true if driver enabled IRQ
* @virq: the virtual IRQ value provided to the requesting driver.
+ * @instance: ida instance which is the mapping index in the irq map
+ * @enabled: true if driver enabled IRQ
*
* Every MSI/MSI-X IRQ requested for a device in a VMD domain will be mapped to
* a VMD IRQ using this structure.
@@ -51,8 +53,10 @@ struct vmd_irq {
struct list_head node;
struct rcu_head rcu;
struct vmd_irq_list *irq;
- bool enabled;
unsigned int virq;
+ int instance;
+ bool enabled;
+ u8 __pad[8];
};
/**
@@ -74,6 +78,9 @@ struct vmd_dev {
int msix_count;
struct vmd_irq_list *irqs;
+ struct vmd_irq *irq_map;
+ struct ida *map_idas;
+#define VMD_IRQS_PER_MAP (PAGE_SIZE / sizeof(struct vmd_irq))
struct pci_sysdata sysdata;
struct resource resources[3];
@@ -96,6 +103,11 @@ static inline unsigned int index_from_irqs(struct vmd_dev *vmd,
{
return irqs - vmd->irqs;
}
+static inline unsigned int index_from_vmd_irq(struct vmd_dev *vmd,
+ struct vmd_irq *vmd_irq)
+{
+ return ((void *)vmd_irq - (void *)vmd->irq_map) / PAGE_SIZE;
+}
/*
* Drivers managing a device in a VMD domain allocate their own IRQs as before,
@@ -201,16 +213,31 @@ static int vmd_msi_init(struct irq_domain *domain, struct msi_domain_info *info,
{
struct msi_desc *desc = arg->desc;
struct vmd_dev *vmd = vmd_from_bus(msi_desc_to_pci_dev(desc)->bus);
- struct vmd_irq *vmdirq = kzalloc(sizeof(*vmdirq), GFP_KERNEL);
+ struct vmd_irq *vmdirq;
+ struct vmd_irq_list *irq;
unsigned int index, vector;
-
- if (!vmdirq)
- return -ENOMEM;
+ int instance;
+
+ irq = vmd_next_irq(vmd, desc);
+ index = index_from_irqs(vmd, irq);
+ instance = ida_simple_get(&vmd->map_idas[index], 0, VMD_IRQS_PER_MAP,
+ GFP_KERNEL);
+ if (instance < 0) {
+ vmdirq = kzalloc(sizeof(*vmdirq), GFP_KERNEL);
+ if (!vmdirq) {
+ BUG_ON(1);
+ return -ENOMEM;
+ }
+ } else {
+ struct vmd_irq *base = (void *)vmd->irq_map + index * PAGE_SIZE;
+ vmdirq = &base[instance];
+ memset(vmdirq, 0, sizeof(*vmdirq));
+ }
INIT_LIST_HEAD(&vmdirq->node);
- vmdirq->irq = vmd_next_irq(vmd, desc);
+ vmdirq->irq = irq;
vmdirq->virq = virq;
- index = index_from_irqs(vmd, vmdirq->irq);
+ vmdirq->instance = instance;
vector = pci_irq_vector(vmd->dev, index);
irq_domain_set_info(domain, virq, vector, info->chip, vmdirq,
@@ -221,6 +248,7 @@ static int vmd_msi_init(struct irq_domain *domain, struct msi_domain_info *info,
static void vmd_msi_free(struct irq_domain *domain,
struct msi_domain_info *info, unsigned int virq)
{
+ struct vmd_dev *vmd = irq_get_handler_data(virq);
struct vmd_irq *vmdirq = irq_get_chip_data(virq);
unsigned long flags;
@@ -229,9 +257,15 @@ static void vmd_msi_free(struct irq_domain *domain,
/* XXX: Potential optimization to rebalance */
raw_spin_lock_irqsave(&list_lock, flags);
vmdirq->irq->count--;
- raw_spin_unlock_irqrestore(&list_lock, flags);
- kfree_rcu(vmdirq, rcu);
+ if (vmdirq->instance < 0) {
+ raw_spin_unlock_irqrestore(&list_lock, flags);
+ kfree_rcu(vmdirq, rcu);
+ } else {
+ unsigned int index = index_from_vmd_irq(vmd, vmdirq);
+ ida_simple_remove(&vmd->map_idas[index], vmdirq->instance);
+ raw_spin_unlock_irqrestore(&list_lock, flags);
+ }
}
static int vmd_msi_prepare(struct irq_domain *domain, struct device *dev,
@@ -694,8 +728,19 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
if (!vmd->irqs)
return -ENOMEM;
+ /* devm_ doesn't provide the PAGE_SIZE alignment we want */
+ vmd->irq_map = kcalloc(vmd->msix_count, PAGE_SIZE, GFP_KERNEL);
+ if (!vmd->irq_map)
+ return -ENOMEM;
+
+ vmd->map_idas = devm_kcalloc(&dev->dev, vmd->msix_count,
+ sizeof(*vmd->map_idas), GFP_KERNEL);
+ if (!vmd->map_idas)
+ return -ENOMEM;
+
for (i = 0; i < vmd->msix_count; i++) {
INIT_LIST_HEAD(&vmd->irqs[i].irq_list);
+ ida_init(&vmd->map_idas[i]);
err = devm_request_irq(&dev->dev, pci_irq_vector(dev, i),
vmd_irq, 0, "vmd", &vmd->irqs[i]);
if (err)
@@ -716,12 +761,16 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
static void vmd_remove(struct pci_dev *dev)
{
struct vmd_dev *vmd = pci_get_drvdata(dev);
+ int i;
vmd_detach_resources(vmd);
pci_set_drvdata(dev, NULL);
sysfs_remove_link(&vmd->dev->dev.kobj, "domain");
pci_stop_root_bus(vmd->bus);
pci_remove_root_bus(vmd->bus);
+ for (i = 0; i < vmd->msix_count; i++)
+ ida_destroy(&vmd->map_idas[i]);
+ kfree(vmd->irq_map);
vmd_teardown_dma_ops(vmd);
irq_domain_remove(vmd->irq_domain);
}
--
1.8.3.1
--
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