Re: [Qemu-devel] [PATCH] linux-user: Safety belt for h2g

["Edgar E. Iglesias" <edgar.iglesias@axis.com>]

On Wed, Dec 03, 2008 at 01:29:39PM +0200, Kirill A. Shutemov wrote:
> From: Jan Kiszka <jan.kiszka@web.de>
> 
> h2g can only work on 64-bit hosts if the provided address is mappable to
> the guest range. Neglecting this was already the source for several
> bugs. Instrument the macro so that it will trigger earlier in the
> future (at least as long as we have this kind of mapping mechanism).
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
> Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>

Acked-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>

> ---
>  cpu-all.h |   10 +++++++++-
>  1 files changed, 9 insertions(+), 1 deletions(-)
> 
> diff --git a/cpu-all.h b/cpu-all.h
> index 73c7b4c..526ace2 100644
> --- a/cpu-all.h
> +++ b/cpu-all.h
> @@ -621,6 +621,9 @@ static inline void stfq_be_p(void *ptr, float64 v)
>  /* MMU memory access macros */
>  
>  #if defined(CONFIG_USER_ONLY)
> +#include <assert.h>
> +#include "qemu-types.h"
> +
>  /* On some host systems the guest address space is reserved on the host.
>   * This allows the guest address space to be offset to a convenient location.
>   */
> @@ -629,7 +632,12 @@ static inline void stfq_be_p(void *ptr, float64 v)
>  
>  /* All direct uses of g2h and h2g need to go away for usermode softmmu.  */
>  #define g2h(x) ((void *)((unsigned long)(x) + GUEST_BASE))
> -#define h2g(x) ((target_ulong)((unsigned long)(x) - GUEST_BASE))
> +#define h2g(x) ({ \
> +    unsigned long __ret = (unsigned long)(x) - GUEST_BASE; \
> +    /* Check if given address fits target address space */ \
> +    assert(__ret == (abi_ulong)__ret); \
> +    (abi_ulong)__ret; \
> +})
>  
>  #define saddr(x) g2h(x)
>  #define laddr(x) g2h(x)
> -- 
> 1.6.0.2.GIT