[PATCH v3 15/27] x86, irq: pre-reserve irq range/realloc for booting path

[Yinghai Lu]

We will use reserve/realloc_irq_and_cfg_at for hotplug ioapic path.

To make thing simple, we could make booting path use same code.

All gsi range will be reserved at first, and realloc will really
allocate those irq_desc/cfg when it is used.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <sebastian@xxxxxxxxxxxxx>
---
 arch/x86/include/asm/io_apic.h |  1 +
 arch/x86/kernel/apic/io_apic.c | 78 ++++++++++++++++++++++++++++++------------
 2 files changed, 57 insertions(+), 22 deletions(-)

diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index eaff3ad..8181fd8 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -176,6 +176,7 @@ extern void setup_ioapic_ids_from_mpc_nocheck(void);
 struct mp_ioapic_gsi{
 	u32 gsi_base;
 	u32 gsi_end;
+	u32 irq_base;
 };
 extern struct mp_ioapic_gsi  mp_gsi_routing[];
 extern u32 gsi_top;
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 23b0be5..65863bd 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -287,8 +287,47 @@ static struct irq_cfg *realloc_irq_and_cfg_at(unsigned int at, int node)
 	return alloc_irq_and_cfg_at(at, node);
 }
 
-/* irq_cfg is indexed by the sum of all RTEs in all I/O APICs. */
-static struct irq_cfg irq_cfgx[NR_IRQS_LEGACY];
+static int reserve_ioapic_gsi_irq_base(int idx)
+{
+	int irq;
+	struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(idx);
+	int cnt = gsi_cfg->gsi_end - gsi_cfg->gsi_base + 1;
+
+	irq = __irq_reserve_irqs(-1, gsi_cfg->gsi_base, cnt);
+	if (irq >= 0) {
+		gsi_cfg->irq_base = irq;
+		apic_printk(APIC_VERBOSE, KERN_INFO
+			"IOAPIC[%d]: apic_id %d, GSI %d-%d ==> irq %d-%d reserved\n",
+			idx, mpc_ioapic_id(idx),
+			gsi_cfg->gsi_base, gsi_cfg->gsi_end,
+			irq, irq + cnt - 1);
+	} else
+		apic_printk(APIC_VERBOSE, KERN_WARNING
+			"IOAPIC[%d]: apic_id %d, GSI %d-%d ==> irq reserve failed\n",
+			idx, mpc_ioapic_id(idx),
+			gsi_cfg->gsi_base, gsi_cfg->gsi_end);
+
+	return irq;
+}
+
+static void __init reserve_ioapic_gsi_irq_extra(void)
+{
+	int irq;
+
+	/* to prevent hot add ioapic taking those slots */
+	if (gsi_top) {
+		irq = irq_reserve_irqs(gsi_top, NR_IRQS_LEGACY);
+		if (irq >= 0)
+			apic_printk(APIC_VERBOSE, KERN_INFO
+				"IOAPIC[extra]: GSI %d-%d ==> irq %d-%d reserved\n",
+				gsi_top, gsi_top + NR_IRQS_LEGACY - 1,
+				irq, irq + NR_IRQS_LEGACY - 1);
+		else
+			apic_printk(APIC_VERBOSE, KERN_WARNING
+				"IOAPIC[extra]: GSI %d-%d ==> irq reserve failed\n",
+				gsi_top, gsi_top + NR_IRQS_LEGACY - 1);
+	}
+}
 
 static void alloc_ioapic_saved_registers(int idx)
 {
@@ -305,8 +344,9 @@ static void alloc_ioapic_saved_registers(int idx)
 
 int __init arch_early_irq_init(void)
 {
+	int node = cpu_to_node(0);
 	struct irq_cfg *cfg;
-	int count, node, i;
+	int i;
 
 	if (!legacy_pic->nr_legacy_irqs)
 		io_apic_irqs = ~0UL;
@@ -314,26 +354,19 @@ int __init arch_early_irq_init(void)
 	for (i = 0; i < nr_ioapics; i++)
 		alloc_ioapic_saved_registers(i);
 
-	cfg = irq_cfgx;
-	count = ARRAY_SIZE(irq_cfgx);
-	node = cpu_to_node(0);
+	for (i = 0; i < nr_ioapics; i++)
+		reserve_ioapic_gsi_irq_base(i);
 
-	/* Make sure the legacy interrupts are marked in the bitmap */
-	irq_reserve_irqs(0, legacy_pic->nr_legacy_irqs);
+	reserve_ioapic_gsi_irq_extra();
 
-	for (i = 0; i < count; i++) {
-		INIT_LIST_HEAD(&cfg[i].irq_2_pin);
-		irq_set_chip_data(i, &cfg[i]);
-		zalloc_cpumask_var_node(&cfg[i].domain, GFP_KERNEL, node);
-		zalloc_cpumask_var_node(&cfg[i].old_domain, GFP_KERNEL, node);
-		/*
-		 * For legacy IRQ's, start with assigning irq0 to irq15 to
-		 * IRQ0_VECTOR to IRQ15_VECTOR for all cpu's.
-		 */
-		if (i < legacy_pic->nr_legacy_irqs) {
-			cfg[i].vector = IRQ0_VECTOR + i;
-			cpumask_setall(cfg[i].domain);
-		}
+	/*
+	 * For legacy IRQ's, start with assigning irq0 to irq15 to
+	 * IRQ0_VECTOR to IRQ15_VECTOR for all cpu's.
+	 */
+	for (i = 0; i < legacy_pic->nr_legacy_irqs; i++) {
+		cfg = realloc_irq_and_cfg_at(i, node);
+		cfg->vector = IRQ0_VECTOR + i;
+		cpumask_setall(cfg->domain);
 	}
 
 	return 0;
@@ -3467,7 +3500,8 @@ int __init arch_probe_nr_irqs(void)
 	if (nr < nr_irqs)
 		nr_irqs = nr;
 
-	return NR_IRQS_LEGACY;
+	/* x86 arch code will allocate irq_desc/cfg */
+	return 0;
 }
 
 int io_apic_set_pci_routing(struct device *dev, int irq,
-- 
1.8.1.4

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