Re: [PATCH] x86/xen: Calculate __max_logical_packages on PV domains

[Boris Ostrovsky]

On 02/07/2018 06:49 PM, Prarit Bhargava wrote:

The kernel panics on PV domains because native_smp_cpus_done() is
only called for HVM domains.

Calculate __max_logical_packages for PV domains.

Fixes: b4c0a7326f5d ("x86/smpboot: Fix __max_logical_packages estimate")
Signed-off-by: Prarit Bhargava <pra...@redhat.com>
Tested-and-reported-by: Simon Gaiser <si...@invisiblethingslab.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: x...@kernel.org
Cc: Boris Ostrovsky <boris.ostrov...@oracle.com>
Cc: Juergen Gross <jgr...@suse.com>
Cc: Dou Liyang <douly.f...@cn.fujitsu.com>
Cc: Prarit Bhargava <pra...@redhat.com>
Cc: Kate Stewart <kstew...@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Vitaly Kuznetsov <vkuzn...@redhat.com>
Cc: xen-de...@lists.xenproject.org

Reviewed-by: Boris Ostrovsky <boris.ostrov...@oracle.com>

(+ Simon)

---
  arch/x86/include/asm/smp.h |  1 +
  arch/x86/kernel/smpboot.c  | 10 ++++++++--
  arch/x86/xen/smp.c         |  2 ++
  3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 461f53d27708..a4189762b266 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -129,6 +129,7 @@ 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 native_smp_prepare_cpus(unsigned int max_cpus);
+void calculate_max_logical_packages(void);
  void native_smp_cpus_done(unsigned int max_cpus);
  void common_cpu_up(unsigned int cpunum, struct task_struct *tidle);
  int native_cpu_up(unsigned int cpunum, struct task_struct *tidle);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6f27facbaa9b..767573b7f2db 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1281,11 +1281,10 @@ void __init native_smp_prepare_boot_cpu(void)
        cpu_set_state_online(me);
  }

-void __init native_smp_cpus_done(unsigned int max_cpus)

+void __init calculate_max_logical_packages(void)
  {
        int ncpus;

- pr_debug("Boot done\n");

        /*
         * Today neither Intel nor AMD support heterogenous systems so
         * extrapolate the boot cpu's data to all packages.
@@ -1293,6 +1292,13 @@ void __init native_smp_cpus_done(unsigned int max_cpus)
        ncpus = cpu_data(0).booted_cores * topology_max_smt_threads();
        __max_logical_packages = DIV_ROUND_UP(nr_cpu_ids, ncpus);
        pr_info("Max logical packages: %u\n", __max_logical_packages);
+}
+
+void __init native_smp_cpus_done(unsigned int max_cpus)
+{
+       pr_debug("Boot done\n");
+
+       calculate_max_logical_packages();

if (x86_has_numa_in_package)

                set_sched_topology(x86_numa_in_package_topology);
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 77c959cf81e7..7a43b2ae19f1 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -122,6 +122,8 @@ void __init xen_smp_cpus_done(unsigned int max_cpus)

if (xen_hvm_domain())

                native_smp_cpus_done(max_cpus);
+       else
+               calculate_max_logical_packages();

if (xen_have_vcpu_info_placement)

                return;