[PATCH] x86/smp: Factor out parts of native_smp_prepare_cpus()

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

Commit 66558b730f25 ("sched: Add cluster scheduler level for x86")
introduced cpu_l2c_shared_map mask which is expected to be initialized
by smp_op.smp_prepare_cpus(). That commit only updated
native_smp_prepare_cpus() version but not xen_pv_smp_prepare_cpus().
As result Xen PV guests crash in set_cpu_sibling_map().

While the new mask can be allocated in xen_pv_smp_prepare_cpus() one can
see that both versions of smp_prepare_cpus ops share a number of common
operations that can be factored out. So do that instead.

Fixes: 66558b730f25 ("sched: Add cluster scheduler level for x86")
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
 arch/x86/include/asm/smp.h |  1 +
 arch/x86/kernel/smpboot.c  | 19 +++++++++++++------
 arch/x86/xen/smp_pv.c      | 11 ++---------
 3 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 08b0e90623ad..81a0211a372d 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -126,6 +126,7 @@ static inline void arch_send_call_function_ipi_mask(const 
struct cpumask *mask)
 
 void cpu_disable_common(void);
 void native_smp_prepare_boot_cpu(void);
+void smp_prepare_cpus_common(void);
 void native_smp_prepare_cpus(unsigned int max_cpus);
 void calculate_max_logical_packages(void);
 void native_smp_cpus_done(unsigned int max_cpus);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 8241927addff..d7429198c22f 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1350,12 +1350,7 @@ static void __init smp_get_logical_apicid(void)
                cpu0_logical_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
 }
 
-/*
- * Prepare for SMP bootup.
- * @max_cpus: configured maximum number of CPUs, It is a legacy parameter
- *            for common interface support.
- */
-void __init native_smp_prepare_cpus(unsigned int max_cpus)
+void __init smp_prepare_cpus_common(void)
 {
        unsigned int i;
 
@@ -1386,6 +1381,18 @@ void __init native_smp_prepare_cpus(unsigned int 
max_cpus)
        set_sched_topology(x86_topology);
 
        set_cpu_sibling_map(0);
+}
+
+/*
+ * Prepare for SMP bootup.
+ * @max_cpus: configured maximum number of CPUs, It is a legacy parameter
+ *            for common interface support.
+ */
+void __init native_smp_prepare_cpus(unsigned int max_cpus)
+{
+
+       smp_prepare_cpus_common();
+
        init_freq_invariance(false, false);
        smp_sanity_check();
 
diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
index 9e55bcbfcd33..69e91d0d3ca4 100644
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -238,16 +238,9 @@ static void __init xen_pv_smp_prepare_cpus(unsigned int 
max_cpus)
        }
        xen_init_lock_cpu(0);
 
-       smp_store_boot_cpu_info();
-       cpu_data(0).x86_max_cores = 1;
+       smp_prepare_cpus_common();
 
-       for_each_possible_cpu(i) {
-               zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
-               zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
-               zalloc_cpumask_var(&per_cpu(cpu_die_map, i), GFP_KERNEL);
-               zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
-       }
-       set_cpu_sibling_map(0);
+       cpu_data(0).x86_max_cores = 1;
 
        speculative_store_bypass_ht_init();
 
-- 
1.8.3.1