RE: [PATCH-for-5.1] accel/xen: Fix xen_enabled() behavior on target-agnostic objects

[Paul Durrant <xadimgnik@xxxxxxxxx>]

> -----Original Message-----
> From: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
> Sent: 28 July 2020 11:09
> To: qemu-devel@xxxxxxxxxx
> Cc: Paul Durrant <paul@xxxxxxx>; Paolo Bonzini <pbonzini@xxxxxxxxxx>; 
> xen-devel@xxxxxxxxxxxxxxxxxxxx;
> Stefano Stabellini <sstabellini@xxxxxxxxxx>; Anthony Perard 
> <anthony.perard@xxxxxxxxxx>; Philippe
> Mathieu-Daudé <philmd@xxxxxxxxxx>; Paul Durrant <pdurrant@xxxxxxxxxx>; Peter 
> Maydell
> <peter.maydell@xxxxxxxxxx>
> Subject: [PATCH-for-5.1] accel/xen: Fix xen_enabled() behavior on 
> target-agnostic objects
> 
> CONFIG_XEN is generated by configure and stored in "config-target.h",
> which is (obviously) only include for target-specific objects.
> This is a problem for target-agnostic objects as CONFIG_XEN is never
> defined and xen_enabled() is always inlined as 'false'.
> 
> Fix by following the KVM schema, defining CONFIG_XEN_IS_POSSIBLE
> when we don't know to force the call of the non-inlined function,
> returning the xen_allowed boolean.
> 
> Fixes: da278d58a092 ("accel: Move Xen accelerator code under accel/xen/")
> Reported-by: Paul Durrant <pdurrant@xxxxxxxxxx>
> Suggested-by: Peter Maydell <peter.maydell@xxxxxxxxxx>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>

Tested-by: Paul Durrant <paul@xxxxxxx>

> ---
>  include/sysemu/xen.h | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/include/sysemu/xen.h b/include/sysemu/xen.h
> index 1ca292715e..385a1fa2bf 100644
> --- a/include/sysemu/xen.h
> +++ b/include/sysemu/xen.h
> @@ -8,7 +8,15 @@
>  #ifndef SYSEMU_XEN_H
>  #define SYSEMU_XEN_H
> 
> -#ifdef CONFIG_XEN
> +#ifdef NEED_CPU_H
> +# ifdef CONFIG_XEN
> +#  define CONFIG_XEN_IS_POSSIBLE
> +# endif
> +#else
> +# define CONFIG_XEN_IS_POSSIBLE
> +#endif
> +
> +#ifdef CONFIG_XEN_IS_POSSIBLE
> 
>  bool xen_enabled(void);
> 
> @@ -18,7 +26,7 @@ void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size,
>                     struct MemoryRegion *mr, Error **errp);
>  #endif
> 
> -#else /* !CONFIG_XEN */
> +#else /* !CONFIG_XEN_IS_POSSIBLE */
> 
>  #define xen_enabled() 0
>  #ifndef CONFIG_USER_ONLY
> @@ -33,6 +41,6 @@ static inline void xen_ram_alloc(ram_addr_t ram_addr, 
> ram_addr_t size,
>  }
>  #endif
> 
> -#endif /* CONFIG_XEN */
> +#endif /* CONFIG_XEN_IS_POSSIBLE */
> 
>  #endif
> --
> 2.21.3