Subject: Re: [PATCH v3 3/3] kvm/powerpc: Export HCALL reason codes

From: Scott Wood <[email-masked]>
Date: Mon, 11 May 2015 17:14:27 -0500

On Fri, 2015-05-08 at 06:23 +0530, Hemant Kumar wrote:
> For perf to analyze the KVM events like hcalls, we need the
> hypervisor calls and their codes to be exported through uapi.
> 
> This patch moves most of the pSeries hcall codes from
> arch/powerpc/include/asm/hvcall.h to
> arch/powerpc/include/uapi/asm/hcall_codes.h.
> It also moves the mapping <hcall_code-to-hcall_reason> from
> arch/powerpc/kvm/trace_hv.h to
> arch/powerpc/include/uapi/asm/trace_hcall.h.
> 
> Signed-off-by: Hemant Kumar <[email-masked]>
> ---
>  arch/powerpc/include/asm/hvcall.h           | 120 +--------------------------
>  arch/powerpc/include/uapi/asm/hcall_codes.h | 123 ++++++++++++++++++++++++++++
>  arch/powerpc/include/uapi/asm/trace_hcall.h | 122 +++++++++++++++++++++++++++
>  arch/powerpc/kvm/trace_hv.h                 | 117 +-------------------------

When moving to uapi please add proper namespacing to indicate that this
is pseries specific.

> diff --git a/arch/powerpc/include/uapi/asm/trace_hcall.h b/arch/powerpc/include/uapi/asm/trace_hcall.h
> new file mode 100644
> index 0000000..00eac01
> --- /dev/null
> +++ b/arch/powerpc/include/uapi/asm/trace_hcall.h
> @@ -0,0 +1,122 @@
> +#ifndef _KVM_TRACE_HCALL_MAP_H
> +#define _KVM_TRACE_HCALL_MAP_H
> +
> +#include "hcall_codes.h"
> +
> +#define kvm_trace_symbol_hcall\
> +	{H_REMOVE,"H_REMOVE"},					\
> +	{H_ENTER,"H_ENTER"},					\
> +	{H_READ,"H_READ"},					\
> +	{H_CLEAR_MOD,"H_CLEAR_MOD"},				\

This is a rather odd way of exposing an array to userspace...

-Scott