--- /dev/null
+From: Suresh Siddha <suresh.b.siddha@intel.com>
+Subject: x64, x2apic/intr-remap: x2apic cluster mode support
+References: fate #303948 and fate #303984
+Patch-Mainline: queued for .28
+Commit-ID: 12a67cf6851871ca8df42025c94f140c303d0f7f
+
+Signed-off-by: Thomas Renninger <trenn@suse.de>
+
+x2apic cluster mode support.
+
+Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
+Cc: akpm@linux-foundation.org
+Cc: arjan@linux.intel.com
+Cc: andi@firstfloor.org
+Cc: ebiederm@xmission.com
+Cc: jbarnes@virtuousgeek.org
+Cc: steiner@sgi.com
+Signed-off-by: Ingo Molnar <mingo@elte.hu>
+
+---
+ arch/x86/kernel/Makefile | 1
+ arch/x86/kernel/genapic_64.c | 3
+ arch/x86/kernel/genx2apic_cluster.c | 135 ++++++++++++++++++++++++++++++++++++
+ include/asm-x86/genapic_64.h | 1
+ 4 files changed, 140 insertions(+)
+
+Index: linux-2.6.26/arch/x86/kernel/Makefile
+===================================================================
+--- linux-2.6.26.orig/arch/x86/kernel/Makefile
++++ linux-2.6.26/arch/x86/kernel/Makefile
+@@ -103,6 +103,7 @@ obj-$(CONFIG_OLPC) += olpc.o
+ # 64 bit specific files
+ ifeq ($(CONFIG_X86_64),y)
+ obj-y += genapic_64.o genapic_flat_64.o genx2apic_uv_x.o tlb_uv.o
++ obj-y += genx2apic_cluster.o
+ obj-y += bios_uv.o
+ obj-$(CONFIG_X86_PM_TIMER) += pmtimer_64.o
+ obj-$(CONFIG_AUDIT) += audit_64.o
+Index: linux-2.6.26/arch/x86/kernel/genapic_64.c
+===================================================================
+--- linux-2.6.26.orig/arch/x86/kernel/genapic_64.c
++++ linux-2.6.26/arch/x86/kernel/genapic_64.c
+@@ -16,6 +16,7 @@
+ #include <linux/ctype.h>
+ #include <linux/init.h>
+ #include <linux/hardirq.h>
++#include <linux/dmar.h>
+
+ #include <asm/smp.h>
+ #include <asm/ipi.h>
+@@ -38,6 +39,8 @@ void __init setup_apic_routing(void)
+ {
+ if (uv_system_type == UV_NON_UNIQUE_APIC)
+ genapic = &apic_x2apic_uv_x;
++ else if (cpu_has_x2apic && intr_remapping_enabled)
++ genapic = &apic_x2apic_cluster;
+ else
+ #ifdef CONFIG_ACPI
+ /*
+Index: linux-2.6.26/arch/x86/kernel/genx2apic_cluster.c
+===================================================================
+--- /dev/null
++++ linux-2.6.26/arch/x86/kernel/genx2apic_cluster.c
+@@ -0,0 +1,135 @@
++#include <linux/threads.h>
++#include <linux/cpumask.h>
++#include <linux/string.h>
++#include <linux/kernel.h>
++#include <linux/ctype.h>
++#include <linux/init.h>
++#include <asm/smp.h>
++#include <asm/ipi.h>
++#include <asm/genapic.h>
++
++DEFINE_PER_CPU(u32, x86_cpu_to_logical_apicid);
++
++/* Start with all IRQs pointing to boot CPU. IRQ balancing will shift them. */
++
++static cpumask_t x2apic_target_cpus(void)
++{
++ return cpumask_of_cpu(0);
++}
++
++/*
++ * for now each logical cpu is in its own vector allocation domain.
++ */
++static cpumask_t x2apic_vector_allocation_domain(int cpu)
++{
++ cpumask_t domain = CPU_MASK_NONE;
++ cpu_set(cpu, domain);
++ return domain;
++}
++
++static void __x2apic_send_IPI_dest(unsigned int apicid, int vector,
++ unsigned int dest)
++{
++ unsigned long cfg;
++
++ cfg = __prepare_ICR(0, vector, dest);
++
++ /*
++ * send the IPI.
++ */
++ x2apic_icr_write(cfg, apicid);
++}
++
++/*
++ * for now, we send the IPI's one by one in the cpumask.
++ * TBD: Based on the cpu mask, we can send the IPI's to the cluster group
++ * at once. We have 16 cpu's in a cluster. This will minimize IPI register
++ * writes.
++ */
++static void x2apic_send_IPI_mask(cpumask_t mask, int vector)
++{
++ unsigned long flags;
++ unsigned long query_cpu;
++
++ local_irq_save(flags);
++ for_each_cpu_mask(query_cpu, mask) {
++ __x2apic_send_IPI_dest(per_cpu(x86_cpu_to_logical_apicid, query_cpu),
++ vector, APIC_DEST_LOGICAL);
++ }
++ local_irq_restore(flags);
++}
++
++static void x2apic_send_IPI_allbutself(int vector)
++{
++ cpumask_t mask = cpu_online_map;
++
++ cpu_clear(smp_processor_id(), mask);
++
++ if (!cpus_empty(mask))
++ x2apic_send_IPI_mask(mask, vector);
++}
++
++static void x2apic_send_IPI_all(int vector)
++{
++ x2apic_send_IPI_mask(cpu_online_map, vector);
++}
++
++static int x2apic_apic_id_registered(void)
++{
++ return 1;
++}
++
++static unsigned int x2apic_cpu_mask_to_apicid(cpumask_t cpumask)
++{
++ int cpu;
++
++ /*
++ * We're using fixed IRQ delivery, can only return one phys APIC ID.
++ * May as well be the first.
++ */
++ cpu = first_cpu(cpumask);
++ if ((unsigned)cpu < NR_CPUS)
++ return per_cpu(x86_cpu_to_logical_apicid, cpu);
++ else
++ return BAD_APICID;
++}
++
++static unsigned int x2apic_read_id(void)
++{
++ return apic_read(APIC_ID);
++}
++
++static unsigned int phys_pkg_id(int index_msb)
++{
++ return x2apic_read_id() >> index_msb;
++}
++
++static void x2apic_send_IPI_self(int vector)
++{
++ apic_write(APIC_SELF_IPI, vector);
++}
++
++static void init_x2apic_ldr(void)
++{
++ int cpu = smp_processor_id();
++
++ per_cpu(x86_cpu_to_logical_apicid, cpu) = apic_read(APIC_LDR);
++ return;
++}
++
++struct genapic apic_x2apic_cluster = {
++ .name = "cluster x2apic",
++ .int_delivery_mode = dest_LowestPrio,
++ .int_dest_mode = (APIC_DEST_LOGICAL != 0),
++ .target_cpus = x2apic_target_cpus,
++ .vector_allocation_domain = x2apic_vector_allocation_domain,
++ .apic_id_registered = x2apic_apic_id_registered,
++ .init_apic_ldr = init_x2apic_ldr,
++ .send_IPI_all = x2apic_send_IPI_all,
++ .send_IPI_allbutself = x2apic_send_IPI_allbutself,
++ .send_IPI_mask = x2apic_send_IPI_mask,
++ .send_IPI_self = x2apic_send_IPI_self,
++ .cpu_mask_to_apicid = x2apic_cpu_mask_to_apicid,
++ .phys_pkg_id = phys_pkg_id,
++ .read_apic_id = x2apic_read_id,
++};
+Index: linux-2.6.26/include/asm-x86/genapic_64.h
+===================================================================
+--- linux-2.6.26.orig/include/asm-x86/genapic_64.h
++++ linux-2.6.26/include/asm-x86/genapic_64.h
+@@ -35,6 +35,7 @@ extern struct genapic *genapic;
+
+ extern struct genapic apic_flat;
+ extern struct genapic apic_physflat;
++extern struct genapic apic_x2apic_cluster;
+ extern int acpi_madt_oem_check(char *, char *);
+
+ extern void apic_send_IPI_self(int vector);