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Subject[PATCH 4/4] x86-64: Support for multiple MSIs
Date
Implement the arch_setup_msi_block() interface.  Rewrite create_irq()
into create_irq_block() and call create_irq_block() from create_irq().
Implement __assign_irq_vector_block() based closely on __assign_irq_vector().

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
arch/x86/kernel/io_apic_64.c | 199 ++++++++++++++++++++++++++++++++++++++----
1 files changed, 183 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index ef1a8df..44e942a 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -683,6 +683,8 @@ static int pin_2_irq(int idx, int apic, int pin)
return irq;
}

+static int current_vector = FIRST_DEVICE_VECTOR;
+
static int __assign_irq_vector(int irq, cpumask_t mask)
{
/*
@@ -696,7 +698,7 @@ static int __assign_irq_vector(int irq, cpumask_t mask)
* Also, we've got to be careful not to trash gate
* 0x80, because int 0x80 is hm, kind of importantish. ;)
*/
- static int current_vector = FIRST_DEVICE_VECTOR, current_offset = 0;
+ static int current_offset = 0;
unsigned int old_vector;
int cpu;
struct irq_cfg *cfg;
@@ -769,6 +771,97 @@ static int assign_irq_vector(int irq, cpumask_t mask)
return err;
}

+static int __assign_irq_vector_block(int irq, int count, cpumask_t mask)
+{
+ unsigned int old_vector;
+ int i, cpu;
+ struct irq_cfg *cfg;
+
+ /*
+ * We've got to be careful not to trash gate 0x80,
+ * because int 0x80 is hm, kind of importantish. ;)
+ */
+ BUG_ON((unsigned)irq + count > NR_IRQS);
+
+ /* Only try and allocate irqs on cpus that are present */
+ cpus_and(mask, mask, cpu_online_map);
+
+ for (i = 0; i < count; i++) {
+ cfg = &irq_cfg[irq + i];
+ if ((cfg->move_in_progress) || cfg->move_cleanup_count)
+ return -EBUSY;
+ }
+
+ cfg = &irq_cfg[irq];
+ old_vector = cfg->vector;
+ if (old_vector) {
+ cpumask_t tmp;
+ cpus_and(tmp, cfg->domain, mask);
+ if (!cpus_empty(tmp))
+ return 0;
+ }
+
+ for_each_cpu_mask(cpu, mask) {
+ cpumask_t domain, new_mask;
+ int new_cpu;
+ int vector;
+
+ domain = vector_allocation_domain(cpu);
+ cpus_and(new_mask, domain, cpu_online_map);
+
+ vector = current_vector & ~(count - 1);
+ next:
+ vector += count;
+ if (vector + count >= FIRST_SYSTEM_VECTOR) {
+ vector = FIRST_DEVICE_VECTOR & ~(count - 1);
+ if (vector < FIRST_DEVICE_VECTOR)
+ vector += count;
+ }
+ if (unlikely(vector == (current_vector & ~(count - 1))))
+ continue;
+ if ((IA32_SYSCALL_VECTOR >= vector) &&
+ (IA32_SYSCALL_VECTOR < vector + count))
+ goto next;
+ for_each_cpu_mask(new_cpu, new_mask) {
+ for (i = 0; i < count; i++) {
+ if (per_cpu(vector_irq, new_cpu)[vector + i]
+ != -1)
+ goto next;
+ }
+ }
+ /* Found one! */
+ current_vector = vector + count - 1;
+ for (i = 0; i < count; i++) {
+ cfg = &irq_cfg[irq + i];
+ if (old_vector) {
+ cfg->move_in_progress = 1;
+ cfg->old_domain = cfg->domain;
+ }
+ for_each_cpu_mask(new_cpu, new_mask) {
+ per_cpu(vector_irq, new_cpu)[vector + i] =
+ irq + i;
+ }
+ cfg->vector = vector;
+ cfg->domain = domain;
+ }
+ return 0;
+ }
+ return -ENOSPC;
+}
+
+/* Assumes that count is a power of two and aligns to that power of two */
+static int assign_irq_vector_block(int irq, int count, cpumask_t mask)
+{
+ int result;
+ unsigned long flags;
+
+ spin_lock_irqsave(&vector_lock, flags);
+ result = __assign_irq_vector_block(irq, count, mask);
+ spin_unlock_irqrestore(&vector_lock, flags);
+
+ return result;
+}
+
static void __clear_irq_vector(int irq)
{
struct irq_cfg *cfg;
@@ -788,6 +881,14 @@ static void __clear_irq_vector(int irq)
cpus_clear(cfg->domain);
}

+static void __clear_irq_vector_block(int irq, int count)
+{
+ while (count > 0) {
+ count--;
+ __clear_irq_vector(irq + count);
+ }
+}
+
void __setup_vector_irq(int cpu)
{
/* Initialize vector_irq on a new cpu */
@@ -1895,30 +1996,56 @@ device_initcall(ioapic_init_sysfs);
/*
* Dynamic irq allocate and deallocation
*/
-int create_irq(void)
+
+/*
+ * On success, returns the interrupt number of the lowest numbered irq
+ * in the block. If it can't find a block of the right size, it returns
+ * -1 - (length of the longest run).
+ */
+static int create_irq_block(int count)
{
- /* Allocate an unused irq */
- int irq;
- int new;
+ /* Allocate 'count' consecutive unused irqs */
+ int i, new, longest;
unsigned long flags;

- irq = -ENOSPC;
+ longest = 0;
spin_lock_irqsave(&vector_lock, flags);
for (new = (NR_IRQS - 1); new >= 0; new--) {
if (platform_legacy_irq(new))
- continue;
+ goto clear;
if (irq_cfg[new].vector != 0)
+ goto clear;
+ longest++;
+ if (longest < count)
continue;
- if (__assign_irq_vector(new, TARGET_CPUS) == 0)
- irq = new;
+
+ while (__assign_irq_vector_block(new, longest, TARGET_CPUS))
+ longest /= 2;
+ if (longest < count)
+ __clear_irq_vector_block(new, longest);
break;
+ clear:
+ __clear_irq_vector_block(new + 1, longest);
+ longest = 0;
}
spin_unlock_irqrestore(&vector_lock, flags);

- if (irq >= 0) {
- dynamic_irq_init(irq);
+ if (longest < count)
+ return -1 - longest;
+
+ for (i = 0; i < count; i++) {
+ dynamic_irq_init(new + i);
}
- return irq;
+
+ return new;
+}
+
+int create_irq(void)
+{
+ int ret = create_irq_block(1);
+ if (ret < 0)
+ return -ENOSPC;
+ return ret;
}

void destroy_irq(unsigned int irq)
@@ -1936,7 +2063,8 @@ void destroy_irq(unsigned int irq)
* MSI message composition
*/
#ifdef CONFIG_PCI_MSI
-static int msi_compose_msg(struct pci_dev *pdev, unsigned int irq, struct msi_msg *msg)
+static int msi_compose_msg(struct pci_dev *pdev, unsigned int irq,
+ unsigned int count, struct msi_msg *msg)
{
struct irq_cfg *cfg = irq_cfg + irq;
int err;
@@ -1944,7 +2072,10 @@ static int msi_compose_msg(struct pci_dev *pdev, unsigned int irq, struct msi_ms
cpumask_t tmp;

tmp = TARGET_CPUS;
- err = assign_irq_vector(irq, tmp);
+ if (count == 1)
+ err = assign_irq_vector(irq, tmp);
+ else
+ err = assign_irq_vector_block(irq, count, tmp);
if (!err) {
cpus_and(tmp, cfg->domain, tmp);
dest = cpu_mask_to_apicid(tmp);
@@ -1975,6 +2106,7 @@ static int msi_compose_msg(struct pci_dev *pdev, unsigned int irq, struct msi_ms
static void set_msi_irq_affinity(unsigned int irq, cpumask_t mask)
{
struct irq_cfg *cfg = irq_cfg + irq;
+ struct msi_desc *desc = get_irq_msi(irq);
struct msi_msg msg;
unsigned int dest;
cpumask_t tmp;
@@ -1983,6 +2115,10 @@ static void set_msi_irq_affinity(unsigned int irq, cpumask_t mask)
if (cpus_empty(tmp))
return;

+ /* XXX: Figure out how to do CPU affinity for multiple MSIs */
+ if (desc->msi_attrib.multiple)
+ return;
+
if (assign_irq_vector(irq, mask))
return;

@@ -2024,7 +2160,7 @@ int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
if (irq < 0)
return irq;

- ret = msi_compose_msg(dev, irq, &msg);
+ ret = msi_compose_msg(dev, irq, 1, &msg);
if (ret < 0) {
destroy_irq(irq);
return ret;
@@ -2038,6 +2174,37 @@ int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
return 0;
}

+int arch_setup_msi_block(struct pci_dev *pdev, struct msi_desc *desc, int count)
+{
+ struct msi_msg msg;
+ int i, ret, base_irq, alloc;
+
+ /* MSI can only allocate a power-of-two */
+ alloc = roundup_pow_of_two(count);
+
+ base_irq = create_irq_block(alloc);
+ if (base_irq < 0)
+ return rounddown_pow_of_two(-base_irq - 1);
+
+ ret = msi_compose_msg(pdev, base_irq, alloc, &msg);
+ if (ret)
+ return ret;
+
+ desc->msi_attrib.multiple = order_base_2(alloc);
+
+ /* Do loop in reverse so set_irq_msi ends up setting
+ * desc->irq to base_irq
+ */
+ for (i = count - 1; i >= 0; i--) {
+ set_irq_msi(base_irq + i, desc);
+ set_irq_chip_and_handler_name(base_irq + i, &msi_chip,
+ handle_edge_irq, "edge");
+ }
+ write_msi_msg(base_irq, &msg);
+
+ return 0;
+}
+
void arch_teardown_msi_irq(unsigned int irq)
{
destroy_irq(irq);
@@ -2090,7 +2257,7 @@ int arch_setup_dmar_msi(unsigned int irq)
int ret;
struct msi_msg msg;

- ret = msi_compose_msg(NULL, irq, &msg);
+ ret = msi_compose_msg(NULL, irq, 1, &msg);
if (ret < 0)
return ret;
dmar_msi_write(irq, &msg);
--
1.5.5.4


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