Re: [PATCH v2 06/17] linux-user: Do not use guest_addr_valid for h2g_valid

[Peter Maydell]

On Fri, 5 Jun 2020 at 05:17, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> This is the only use of guest_addr_valid that does not begin
> with a guest address, but a host address being transformed to
> a guest address.
>
> We will shortly adjust guest_addr_valid to handle guest memory
> tags, and the host address should not be subjected to that.
>
> Move h2g_valid adjacent to the other h2g macros.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  include/exec/cpu_ldst.h | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/include/exec/cpu_ldst.h b/include/exec/cpu_ldst.h
> index c14a48f65e..3930362e20 100644
> --- a/include/exec/cpu_ldst.h
> +++ b/include/exec/cpu_ldst.h
> @@ -77,15 +77,16 @@ typedef uint64_t abi_ptr;
>  #else
>  #define guest_addr_valid(x) ((x) <= GUEST_ADDR_MAX)
>  #endif
> -#define h2g_valid(x) guest_addr_valid((unsigned long)(x) - guest_base)
>
>  static inline int guest_range_valid(unsigned long start, unsigned long len)
>  {
>      return len - 1 <= GUEST_ADDR_MAX && start <= GUEST_ADDR_MAX - len + 1;
>  }
>
> +#define h2g_valid(x)  ((uintptr_t)(x) - guest_base <= GUEST_ADDR_MAX)

The old implementation returns true for
HOST_LONG_BITS <= TARGET_VIRT_ADDR_SPACE_BITS
(because there's a different definition of guest_addr_valid() there)
but this one does a range check even in that case.

> +
>  #define h2g_nocheck(x) ({ \
> -    unsigned long __ret = (unsigned long)(x) - guest_base; \
> +    uintptr_t __ret = (uintptr_t)(x) - guest_base; \
>      (abi_ptr)__ret; \
>  })

Why the type change? This seems unrelated.

thanks
-- PMM