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

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

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 <prarit@xxxxxxxxxx>
> Tested-and-reported-by: Simon Gaiser <simon@xxxxxxxxxxxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: x86@xxxxxxxxxx
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: Juergen Gross <jgross@xxxxxxxx>
> Cc: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
> Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
> Cc: Kate Stewart <kstewart@xxxxxxxxxxxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxx>
> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>

(+ 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;
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