Re: [Xen-devel] [PATCH v3 4/5] x86/hyperv: retrieve vp_index from Hyper-V

[Paul Durrant <pdurrant@xxxxxxxxx>]

On Sun, 5 Jan 2020 at 16:49, Wei Liu <wl@xxxxxxx> wrote:
>
> This will be useful when invoking hypercall that targets specific
> vcpu(s).
>
> Signed-off-by: Wei Liu <liuwe@xxxxxxxxxxxxx>

Reviewed-by: Paul Durrant <paul@xxxxxxx>

> ---
> v2:
> 1. Fold into setup_pcpu_arg function
> ---
>  xen/arch/x86/guest/hyperv/hyperv.c | 5 +++++
>  xen/include/asm-x86/guest/hyperv.h | 1 +
>  2 files changed, 6 insertions(+)
>
> diff --git a/xen/arch/x86/guest/hyperv/hyperv.c 
> b/xen/arch/x86/guest/hyperv/hyperv.c
> index 7e046dfc04..e5f258c946 100644
> --- a/xen/arch/x86/guest/hyperv/hyperv.c
> +++ b/xen/arch/x86/guest/hyperv/hyperv.c
> @@ -28,6 +28,7 @@ struct ms_hyperv_info __read_mostly ms_hyperv;
>
>  extern char hv_hypercall_page[];
>  DEFINE_PER_CPU_READ_MOSTLY(void *, hv_pcpu_input_arg);
> +DEFINE_PER_CPU_READ_MOSTLY(unsigned int, hv_vp_index);
>
>  static const struct hypervisor_ops ops;
>  const struct hypervisor_ops *__init hyperv_probe(void)
> @@ -87,6 +88,7 @@ static void __init setup_hypercall_page(void)
>  static void setup_hypercall_pcpu_arg(void)
>  {
>      void *mapping;
> +    uint64_t vp_index_msr;
>
>      mapping = alloc_xenheap_page();
>      if ( !mapping )
> @@ -94,6 +96,9 @@ static void setup_hypercall_pcpu_arg(void)
>                smp_processor_id());
>
>      this_cpu(hv_pcpu_input_arg) = mapping;
> +
> +    rdmsrl(HV_X64_MSR_VP_INDEX, vp_index_msr);
> +    this_cpu(hv_vp_index) = vp_index_msr;
>  }
>
>  static void __init setup(void)
> diff --git a/xen/include/asm-x86/guest/hyperv.h 
> b/xen/include/asm-x86/guest/hyperv.h
> index 6cf2eab62f..bae06c8a3a 100644
> --- a/xen/include/asm-x86/guest/hyperv.h
> +++ b/xen/include/asm-x86/guest/hyperv.h
> @@ -66,6 +66,7 @@ struct ms_hyperv_info {
>  extern struct ms_hyperv_info ms_hyperv;
>
>  DECLARE_PER_CPU(void *, hv_pcpu_input_arg);
> +DECLARE_PER_CPU(unsigned int, hv_vp_index);
>
>  const struct hypervisor_ops *hyperv_probe(void);
>
> --
> 2.20.1
>

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