x2apic/intr-remap: decouple interrupt remapping from x2apic

interrupt remapping must be enabled before enabling x2apic, but
interrupt remapping doesn't depend on x2apic, it can be used
separately. Enable interrupt remapping in init_dmars even x2apic
is not supported.

[dwmw2: Update Kconfig accordingly, fix build with INTR_REMAP && !X2APIC]
Signed-off-by: Weidong Han <weidong.han@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

arch/x86/Kconfig

@@ -251,6 +251,7 @@ config SMP
 config X86_X2APIC
 	bool "Support x2apic"
 	depends on X86_LOCAL_APIC && X86_64
+	select INTR_REMAP
 	---help---
 	  This enables x2apic support on CPUs that have this feature.
 
@@ -1879,7 +1880,6 @@ config DMAR_FLOPPY_WA
 config INTR_REMAP
 	bool "Support for Interrupt Remapping (EXPERIMENTAL)"
 	depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
-	select X86_X2APIC
 	---help---
 	  Supports Interrupt remapping for IO-APIC and MSI devices.
 	  To use x2apic mode in the CPU's which support x2APIC enhancements or

arch/x86/include/asm/apic.h

@@ -107,11 +107,10 @@ extern u32 native_safe_apic_wait_icr_idle(void);
 extern void native_apic_icr_write(u32 low, u32 id);
 extern u64 native_apic_icr_read(void);
 
-#ifdef CONFIG_X86_X2APIC
-
 #define EIM_8BIT_APIC_ID	0
 #define EIM_32BIT_APIC_ID	1
 
+#ifdef CONFIG_X86_X2APIC
 /*
  * Make previous memory operations globally visible before
  * sending the IPI through x2apic wrmsr. We need a serializing instruction or

arch/x86/kernel/apic/io_apic.c

@@ -2524,7 +2524,7 @@ static void irq_complete_move(struct irq_desc **descp)
 static inline void irq_complete_move(struct irq_desc **descp) {}
 #endif
 
-#ifdef CONFIG_INTR_REMAP
+#ifdef CONFIG_X86_X2APIC
 static void __eoi_ioapic_irq(unsigned int irq, struct irq_cfg *cfg)
 {
 	int apic, pin;
@@ -2569,7 +2569,6 @@ static void ack_x2apic_edge(unsigned int irq)
 {
 	ack_x2APIC_irq();
 }
-
 #endif
 
 static void ack_apic_edge(unsigned int irq)
@@ -2680,6 +2679,26 @@ static void ack_apic_level(unsigned int irq)
 #endif
 }
 
+#ifdef CONFIG_INTR_REMAP
+static void ir_ack_apic_edge(unsigned int irq)
+{
+#ifdef CONFIG_X86_X2APIC
+       if (x2apic_enabled())
+               return ack_x2apic_edge(irq);
+#endif
+       return ack_apic_edge(irq);
+}
+
+static void ir_ack_apic_level(unsigned int irq)
+{
+#ifdef CONFIG_X86_X2APIC
+       if (x2apic_enabled())
+               return ack_x2apic_level(irq);
+#endif
+       return ack_apic_level(irq);
+}
+#endif /* CONFIG_INTR_REMAP */
+
 static struct irq_chip ioapic_chip __read_mostly = {
 	.name		= "IO-APIC",
 	.startup	= startup_ioapic_irq,
@@ -2699,8 +2718,8 @@ static struct irq_chip ir_ioapic_chip __read_mostly = {
 	.mask		= mask_IO_APIC_irq,
 	.unmask		= unmask_IO_APIC_irq,
 #ifdef CONFIG_INTR_REMAP
-	.ack		= ack_x2apic_edge,
-	.eoi		= ack_x2apic_level,
+	.ack		= ir_ack_apic_edge,
+	.eoi		= ir_ack_apic_level,
 #ifdef CONFIG_SMP
 	.set_affinity	= set_ir_ioapic_affinity_irq,
 #endif
@@ -3426,7 +3445,7 @@ static struct irq_chip msi_ir_chip = {
 	.unmask		= unmask_msi_irq,
 	.mask		= mask_msi_irq,
 #ifdef CONFIG_INTR_REMAP
-	.ack		= ack_x2apic_edge,
+	.ack		= ir_ack_apic_edge,
 #ifdef CONFIG_SMP
 	.set_affinity	= ir_set_msi_irq_affinity,
 #endif

drivers/pci/intel-iommu.c

@@ -1947,6 +1947,15 @@ static int __init init_dmars(void)
 		}
 	}
 
+#ifdef CONFIG_INTR_REMAP
+	if (!intr_remapping_enabled) {
+		ret = enable_intr_remapping(0);
+		if (ret)
+			printk(KERN_ERR
+			       "IOMMU: enable interrupt remapping failed\n");
+	}
+#endif
+
 	/*
 	 * For each rmrr
 	 *   for each dev attached to rmrr