Re: [RESEND][PATCH v2 5/7] xen: include xen/guest_access.h rather than asm/guest_access.h

[Jan Beulich <jbeulich@xxxxxxxx>]

On 14.08.2020 21:07, Julien Grall wrote:
> Hi Jan,
> 
> On 31/07/2020 12:36, Jan Beulich wrote:
>> On 30.07.2020 20:18, Julien Grall wrote:
>>> From: Julien Grall <jgrall@xxxxxxxxxx>
>>>
>>> Only a few places are actually including asm/guest_access.h. While this
>>> is fine today, a follow-up patch will want to move most of the helpers
>>> from asm/guest_access.h to xen/guest_access.h.
>>>
>>> To prepare the move, everyone should include xen/guest_access.h rather
>>> than asm/guest_access.h.
>>>
>>> Interestingly, asm-arm/guest_access.h includes xen/guest_access.h. The
>>> inclusion is now removed as no-one but the latter should include the
>>> former.
>>>
>>> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
>>
>> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
>>
>> Is there any chance you could take measures to avoid new inclusions
>> of asm/guest_access.h to appear?
> 
> It should be possible.
> 
> How about this:
> 
> diff --git a/xen/include/asm-arm/guest_access.h 
> b/xen/include/asm-arm/guest_access.h
> index b9a89c495527..d8dbc7c973b4 100644
> --- a/xen/include/asm-arm/guest_access.h
> +++ b/xen/include/asm-arm/guest_access.h
> @@ -1,3 +1,7 @@
> +#ifndef ALLOW_INCLUDE_ASM_GUEST_ACCESS_H
> +#error "asm/guest_access.h should not be included directly"
> +#endif
> +
>  #ifndef __ASM_ARM_GUEST_ACCESS_H__
>  #define __ASM_ARM_GUEST_ACCESS_H__
> 
> diff --git a/xen/include/asm-x86/guest_access.h 
> b/xen/include/asm-x86/guest_access.h
> index 369676f31ac3..e665ca3a27af 100644
> --- a/xen/include/asm-x86/guest_access.h
> +++ b/xen/include/asm-x86/guest_access.h
> @@ -4,6 +4,10 @@
>   * Copyright (c) 2006, K A Fraser
>   */
> 
> +#ifndef ALLOW_INCLUDE_ASM_GUEST_ACCESS_H
> +#error "asm/guest_access.h should not be included directly"
> +#endif
> +
>  #ifndef __ASM_X86_GUEST_ACCESS_H__
>  #define __ASM_X86_GUEST_ACCESS_H__
> 
> diff --git a/xen/include/xen/guest_access.h b/xen/include/xen/guest_access.h
> index 75103d30c8be..814e31329de9 100644
> --- a/xen/include/xen/guest_access.h
> +++ b/xen/include/xen/guest_access.h
> @@ -7,7 +7,9 @@
>  #ifndef __XEN_GUEST_ACCESS_H__
>  #define __XEN_GUEST_ACCESS_H__
> 
> +#define ALLOW_INCLUDE_ASM_GUEST_ACCESS_H
>  #include <asm/guest_access.h>
> +#undef ALLOW_INCLUDE_ASM_GUEST_ACCESS_H
>  #include <xen/types.h>
>  #include <public/xen.h>

One option. Personally I'd prefer to avoid introduction of yet another
constant, by leveraging __XEN_GUEST_ACCESS_H__ instead.

Jan