On Fri, May 11, 2007 at 11:19:14AM +1000, Rusty Russell wrote:
> @@ -218,7 +218,7 @@ u32 lgread_u32(struct lguest *lg, u32 ad
>  
>       /* Don't let them access lguest binary */
>       if (!lguest_address_ok(lg, addr, sizeof(val))
> -         || get_user(val, (u32 __user *)addr) != 0)
> +         || get_user(val, (__force u32 __user *)addr) != 0)
>               kill_guest(lg, "bad read address %u", addr);
>       return val;

*Ahem*

What kind of address are we really getting there?  IOW, where does it
ultimately come from?

>       lock_cpu_hotplug();
>       if (cpu_has_pge) { /* We have a broader idea of "global". */
>               cpu_had_pge = 1;
> -             on_each_cpu(adjust_pge, 0, 0, 1);
> +             on_each_cpu(adjust_pge, (void *)0, 0, 1);

That's called NULL...

>       case LHCALL_LOAD_TLS:
> -             guest_load_tls(lg, (struct desc_struct __user*)regs->edx);
> +             guest_load_tls(lg,
> +                            (__force struct desc_struct __user*)regs->edx);

Umm...  That's borderline OK, but...

>  static void push_guest_stack(struct lguest *lg, u32 __user **gstack, u32 val)
>  {
> -     lgwrite_u32(lg, (u32)--(*gstack), val);
> +     lgwrite_u32(lg, (__force u32)--(*gstack), val);
>  }

Now, _that_ is just plain dumb.  Why not declare that lgwrite_u32() as taking
u32 __user * as argument and kill the casts?

> -     lg->regs->esp = (u32)gstack + lg->page_offset;
> +     lg->regs->esp = (__force u32)gstack + lg->page_offset;

Yuck.  Cast to unsigned long (or uintptr_t), please.  In this case it is
legitimate.
-
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