[Xen-devel] [PATCH linux v3 2/9] x86/acpi: store ACPI ids from MADT for future usage

[Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>]

Currently we don't save ACPI ids (unlike LAPIC ids which go to
x86_cpu_to_apicid) from MADT and we may need this information later.
Particularly, ACPI ids is the only existent way for a PVHVM Xen guest
to figure out Xen's idea of its vCPUs ids before these CPUs boot and
in some cases these ids diverge from Linux's cpu ids.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
 arch/x86/include/asm/cpu.h     |  1 +
 arch/x86/include/asm/smp.h     |  2 ++
 arch/x86/kernel/acpi/boot.c    | 16 ++++++++++++----
 arch/x86/kernel/apic/apic.c    |  2 ++
 arch/x86/kernel/setup_percpu.c |  3 +++
 5 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 59d34c5..9b7fa63 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -16,6 +16,7 @@ extern void prefill_possible_map(void);
 static inline void prefill_possible_map(void) {}
 
 #define cpu_physical_id(cpu)                   boot_cpu_physical_apicid
+#define cpu_acpi_id(cpu)                       0
 #define safe_smp_processor_id()                        0
 
 #endif /* CONFIG_SMP */
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 0576b61..83463c0 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -33,6 +33,7 @@ static inline struct cpumask *cpu_llc_shared_mask(int cpu)
 }
 
 DECLARE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_cpu_to_apicid);
+DECLARE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid);
 DECLARE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_bios_cpu_apicid);
 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
 DECLARE_EARLY_PER_CPU_READ_MOSTLY(int, x86_cpu_to_logical_apicid);
@@ -147,6 +148,7 @@ void x86_idle_thread_init(unsigned int cpu, struct 
task_struct *idle);
 void smp_store_boot_cpu_info(void);
 void smp_store_cpu_info(int id);
 #define cpu_physical_id(cpu)   per_cpu(x86_cpu_to_apicid, cpu)
+#define cpu_acpi_id(cpu)       per_cpu(x86_cpu_to_acpiid, cpu)
 
 #else /* !CONFIG_SMP */
 #define wbinvd_on_cpu(cpu)     wbinvd()
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 9414f84..6738e5c 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -161,13 +161,15 @@ static int __init acpi_parse_madt(struct 
acpi_table_header *table)
 /**
  * acpi_register_lapic - register a local apic and generates a logic cpu number
  * @id: local apic id to register
+ * @acpiid: ACPI id to register
  * @enabled: this cpu is enabled or not
  *
  * Returns the logic cpu number which maps to the local apic
  */
-static int acpi_register_lapic(int id, u8 enabled)
+static int acpi_register_lapic(int id, u32 acpiid, u8 enabled)
 {
        unsigned int ver = 0;
+       int cpu;
 
        if (id >= MAX_LOCAL_APIC) {
                printk(KERN_INFO PREFIX "skipped apicid that is too big\n");
@@ -182,7 +184,11 @@ static int acpi_register_lapic(int id, u8 enabled)
        if (boot_cpu_physical_apicid != -1U)
                ver = apic_version[boot_cpu_physical_apicid];
 
-       return generic_processor_info(id, ver);
+       cpu = generic_processor_info(id, ver);
+       if (cpu >= 0)
+               early_per_cpu(x86_cpu_to_acpiid, cpu) = acpiid;
+
+       return cpu;
 }
 
 static int __init
@@ -212,7 +218,7 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, 
const unsigned long end)
        if (!apic->apic_id_valid(apic_id) && enabled)
                printk(KERN_WARNING PREFIX "x2apic entry ignored\n");
        else
-               acpi_register_lapic(apic_id, enabled);
+               acpi_register_lapic(apic_id, processor->uid, enabled);
 #else
        printk(KERN_WARNING PREFIX "x2apic entry ignored\n");
 #endif
@@ -240,6 +246,7 @@ acpi_parse_lapic(struct acpi_subtable_header * header, 
const unsigned long end)
         * when we use CPU hotplug.
         */
        acpi_register_lapic(processor->id,      /* APIC ID */
+                           processor->processor_id, /* ACPI ID */
                            processor->lapic_flags & ACPI_MADT_ENABLED);
 
        return 0;
@@ -258,6 +265,7 @@ acpi_parse_sapic(struct acpi_subtable_header *header, const 
unsigned long end)
        acpi_table_print_madt_entry(header);
 
        acpi_register_lapic((processor->id << 8) | processor->eid,/* APIC ID */
+                           processor->processor_id, /* ACPI ID */
                            processor->lapic_flags & ACPI_MADT_ENABLED);
 
        return 0;
@@ -714,7 +722,7 @@ int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, 
int *pcpu)
 {
        int cpu;
 
-       cpu = acpi_register_lapic(physid, ACPI_MADT_ENABLED);
+       cpu = acpi_register_lapic(physid, U32_MAX, ACPI_MADT_ENABLED);
        if (cpu < 0) {
                pr_info(PREFIX "Unable to map lapic to logical cpu number\n");
                return cpu;
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index f943d2f..ac8d8ad 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -92,8 +92,10 @@ static int apic_extnmi = APIC_EXTNMI_BSP;
  */
 DEFINE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_cpu_to_apicid, BAD_APICID);
 DEFINE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_bios_cpu_apicid, BAD_APICID);
+DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid, U32_MAX);
 EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_apicid);
 EXPORT_EARLY_PER_CPU_SYMBOL(x86_bios_cpu_apicid);
+EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_acpiid);
 
 #ifdef CONFIG_X86_32
 
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index e4fcb87..7a40e06 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -236,6 +236,8 @@ void __init setup_per_cpu_areas(void)
                        early_per_cpu_map(x86_cpu_to_apicid, cpu);
                per_cpu(x86_bios_cpu_apicid, cpu) =
                        early_per_cpu_map(x86_bios_cpu_apicid, cpu);
+               per_cpu(x86_cpu_to_acpiid, cpu) =
+                       early_per_cpu_map(x86_cpu_to_acpiid, cpu);
 #endif
 #ifdef CONFIG_X86_32
                per_cpu(x86_cpu_to_logical_apicid, cpu) =
@@ -271,6 +273,7 @@ void __init setup_per_cpu_areas(void)
 #ifdef CONFIG_X86_LOCAL_APIC
        early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
        early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
+       early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;
 #endif
 #ifdef CONFIG_X86_32
        early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL;
-- 
2.7.4


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