RE: [PATCH v5 10/16] x86/hyperv: implement and use hv_smp_prepare_cpus

Michael Kelley
2021-01-26T01:41:16Z

From: Wei Liu <wei.liu@kernel.org> Sent: Wednesday, January 20, 2021 4:01 AM
>
> Microsoft Hypervisor requires the root partition to make a few
> hypercalls to setup application processors before they can be used.
>
> Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
> Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
> Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
> Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
> Signed-off-by: Wei Liu <wei.liu@kernel.org>
> ---
> CPU hotplug and unplug is not yet supported in this setup, so those
> paths remain untouched.
>
> v3: Always call native SMP preparation function.
> ---
> arch/x86/kernel/cpu/mshyperv.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index c376d191a260..13d3b6dd21a3 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -31,6 +31,7 @@
> #include <asm/reboot.h>
> #include <asm/nmi.h>
> #include <clocksource/hyperv_timer.h>
> +#include <asm/numa.h>
>
> /* Is Linux running as the root partition? */
> bool hv_root_partition;
> @@ -212,6 +213,32 @@ static void __init hv_smp_prepare_boot_cpu(void)
> hv_init_spinlocks();
> #endif
> }
> +
> +static void __init hv_smp_prepare_cpus(unsigned int max_cpus)
> +{
> +#ifdef CONFIG_X86_64
> + int i;
> + int ret;
> +#endif
> +
> + native_smp_prepare_cpus(max_cpus);
> +
> +#ifdef CONFIG_X86_64
> + for_each_present_cpu(i) {
> + if (i == 0)
> + continue;
> + ret = hv_call_add_logical_proc(numa_cpu_node(i), i, cpu_physical_id(i));
> + BUG_ON(ret);
> + }
> +
> + for_each_present_cpu(i) {
> + if (i == 0)
> + continue;
> + ret = hv_call_create_vp(numa_cpu_node(i), hv_current_partition_id, i, i);
> + BUG_ON(ret);
> + }
> +#endif
> +}
> #endif
>
> static void __init ms_hyperv_init_platform(void)
> @@ -368,6 +395,8 @@ static void __init ms_hyperv_init_platform(void)
>
> # ifdef CONFIG_SMP
> smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
> + if (hv_root_partition)
> + smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
> # endif
>
> /*
> --
> 2.20.1

Reviewed-by: Michael Kelley <mikelley@microsoft.com>