[patch RFC 18/38] x86/irq: Initialize PCI/MSI domain at PCI init time

[Thomas Gleixner <tglx@xxxxxxxxxxxxx>]

No point in initializing the default PCI/MSI interrupt domain early and no
point to create it when XEN PV/HVM/DOM0 are active.

Move the initialization to pci_arch_init() and convert it to init ops so
that XEN can override it as XEN has it's own PCI/MSI management. The XEN
override comes in a later step.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-pci@xxxxxxxxxxxxxxx
---
 arch/x86/include/asm/irqdomain.h |    6 ++++--
 arch/x86/include/asm/x86_init.h  |    3 +++
 arch/x86/kernel/apic/msi.c       |   26 ++++++++++++++++----------
 arch/x86/kernel/apic/vector.c    |    2 --
 arch/x86/kernel/x86_init.c       |    3 ++-
 arch/x86/pci/init.c              |    3 +++
 6 files changed, 28 insertions(+), 15 deletions(-)

--- a/arch/x86/include/asm/irqdomain.h
+++ b/arch/x86/include/asm/irqdomain.h
@@ -51,9 +51,11 @@ extern int mp_irqdomain_ioapic_idx(struc
 #endif /* CONFIG_X86_IO_APIC */
 
 #ifdef CONFIG_PCI_MSI
-extern void arch_init_msi_domain(struct irq_domain *domain);
+void x86_create_pci_msi_domain(void);
+struct irq_domain *native_create_pci_msi_domain(void);
 #else
-static inline void arch_init_msi_domain(struct irq_domain *domain) { }
+static inline void x86_create_pci_msi_domain(void) { }
+#define native_create_pci_msi_domain   NULL
 #endif
 
 #endif
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -8,6 +8,7 @@ struct mpc_bus;
 struct mpc_cpu;
 struct mpc_table;
 struct cpuinfo_x86;
+struct irq_domain;
 
 /**
  * struct x86_init_mpparse - platform specific mpparse ops
@@ -42,12 +43,14 @@ struct x86_init_resources {
  * @intr_init:                 interrupt init code
  * @intr_mode_select:          interrupt delivery mode selection
  * @intr_mode_init:            interrupt delivery mode setup
+ * @create_pci_msi_domain:     Create the PCI/MSI interrupt domain
  */
 struct x86_init_irqs {
        void (*pre_vector_init)(void);
        void (*intr_init)(void);
        void (*intr_mode_select)(void);
        void (*intr_mode_init)(void);
+       struct irq_domain *(*create_pci_msi_domain)(void);
 };
 
 /**
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -21,7 +21,7 @@
 #include <asm/apic.h>
 #include <asm/irq_remapping.h>
 
-static struct irq_domain *msi_default_domain;
+static struct irq_domain *x86_pci_msi_default_domain __ro_after_init;
 
 static void __irq_msi_compose_msg(struct irq_cfg *cfg, struct msi_msg *msg)
 {
@@ -192,7 +192,7 @@ int native_setup_msi_irqs(struct pci_dev
 
        domain = irq_remapping_get_irq_domain(&info);
        if (domain == NULL)
-               domain = msi_default_domain;
+               domain = x86_pci_msi_default_domain;
        if (domain == NULL)
                return -ENOSYS;
 
@@ -243,25 +243,31 @@ static struct msi_domain_info pci_msi_do
        .handler_name   = "edge",
 };
 
-void __init arch_init_msi_domain(struct irq_domain *parent)
+struct irq_domain * __init native_create_pci_msi_domain(void)
 {
        struct fwnode_handle *fn;
+       struct irq_domain *d;
 
        if (disable_apic)
-               return;
+               return NULL;
 
        fn = irq_domain_alloc_named_fwnode("PCI-MSI");
        if (fn) {
-               msi_default_domain =
-                       pci_msi_create_irq_domain(fn, &pci_msi_domain_info,
-                                                 parent);
+               d = pci_msi_create_irq_domain(fn, &pci_msi_domain_info,
+                                             x86_vector_domain);
        }
-       if (!msi_default_domain) {
+       if (!d) {
                irq_domain_free_fwnode(fn);
-               pr_warn("failed to initialize irqdomain for MSI/MSI-x.\n");
+               pr_warn("Failed to initialize PCI-MSI irqdomain.\n");
        } else {
-               msi_default_domain->flags |= IRQ_DOMAIN_MSI_NOMASK_QUIRK;
+               d->flags |= IRQ_DOMAIN_MSI_NOMASK_QUIRK;
        }
+       return d;
+}
+
+void __init x86_create_pci_msi_domain(void)
+{
+       x86_pci_msi_default_domain = x86_init.irqs.create_pci_msi_domain();
 }
 
 #ifdef CONFIG_IRQ_REMAP
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -713,8 +713,6 @@ int __init arch_early_irq_init(void)
        BUG_ON(x86_vector_domain == NULL);
        irq_set_default_host(x86_vector_domain);
 
-       arch_init_msi_domain(x86_vector_domain);
-
        BUG_ON(!alloc_cpumask_var(&vector_searchmask, GFP_KERNEL));
 
        /*
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -76,7 +76,8 @@ struct x86_init_ops x86_init __initdata
                .pre_vector_init        = init_ISA_irqs,
                .intr_init              = native_init_IRQ,
                .intr_mode_select       = apic_intr_mode_select,
-               .intr_mode_init         = apic_intr_mode_init
+               .intr_mode_init         = apic_intr_mode_init,
+               .create_pci_msi_domain  = native_create_pci_msi_domain,
        },
 
        .oem = {
--- a/arch/x86/pci/init.c
+++ b/arch/x86/pci/init.c
@@ -3,6 +3,7 @@
 #include <linux/init.h>
 #include <asm/pci_x86.h>
 #include <asm/x86_init.h>
+#include <asm/irqdomain.h>
 
 /* arch_initcall has too random ordering, so call the initializers
    in the right sequence from here. */
@@ -10,6 +11,8 @@ static __init int pci_arch_init(void)
 {
        int type;
 
+       x86_create_pci_msi_domain();
+
        type = pci_direct_probe();
 
        if (!(pci_probe & PCI_PROBE_NOEARLY))