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From: "Jan-Simon =?utf-8?q?M=C3=B6ller?=" <dl9pf@gmx.de>
Subject: Re: [Qemu-devel] [Patch] linux-user/syscall.c - don't add GUEST_BASE
	to NULL pointer
Date: Wed, 26 Aug 2009 01:37:48 +0200
References: <200908260002.03066.dl9pf@gmx.de>
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To: qemu-devel@nongnu.org

Thinking a bit more about this, I wonder if g2h(x) shouldn't itself always=
=20
return NULL on x =3D NULL ?=20

Something like:

Signed-off-by:  Jan-Simon M=C3=B6ller  <dl9pf@gmx.de>

diff --git a/cpu-all.h b/cpu-all.h
index 1a6a812..631f678 100644
=2D-- a/cpu-all.h
+++ b/cpu-all.h
@@ -633,7 +633,7 @@ extern int have_guest_base;
 #endif

 /* All direct uses of g2h and h2g need to go away for usermode softmmu.  */
=2D#define g2h(x) ((void *)((unsigned long)(x) + GUEST_BASE))
+#define g2h(x) ( !x ? NULL:((void *)((unsigned long)(x) + GUEST_BASE)))
 #define h2g(x) ({ \
     unsigned long __ret =3D (unsigned long)(x) - GUEST_BASE; \
     /* Check if given address fits target address space */ \


I read the comment above, but before replacing it in user-mode (if possible=
),=20
we should fix it ;) .


Best,
Jan-Simon