Module Name:    src
Committed By:   jym
Date:           Tue Mar  9 23:12:06 UTC 2010

Modified Files:
        src/sys/arch/xen/x86: xen_bus_dma.c

Log Message:
Although Xen's documentation states that the address_bits field is not used
by XENMEM_decrease_reservation, it is checked by the hypervisor. In certain
circumstances (stack leak), the field could have an improper value, leading
to a fail of the hypercall.

Set it to 0 ("no addressing restriction") to avoid that.

Patch tested by Sam Fourman and h...@.

This should fix the rare "failed allocating DMA memory" encountered
under NetBSD dom0. Will ask for a pull-up.


To generate a diff of this commit:
cvs rdiff -u -r1.19 -r1.20 src/sys/arch/xen/x86/xen_bus_dma.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/arch/xen/x86/xen_bus_dma.c
diff -u src/sys/arch/xen/x86/xen_bus_dma.c:1.19 src/sys/arch/xen/x86/xen_bus_dma.c:1.20
--- src/sys/arch/xen/x86/xen_bus_dma.c:1.19	Tue Mar  2 00:13:50 2010
+++ src/sys/arch/xen/x86/xen_bus_dma.c	Tue Mar  9 23:12:06 2010
@@ -1,4 +1,4 @@
-/*	$NetBSD: xen_bus_dma.c,v 1.19 2010/03/02 00:13:50 jym Exp $	*/
+/*	$NetBSD: xen_bus_dma.c,v 1.20 2010/03/09 23:12:06 jym Exp $	*/
 /*	NetBSD bus_dma.c,v 1.21 2005/04/16 07:53:35 yamt Exp */
 
 /*-
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xen_bus_dma.c,v 1.19 2010/03/02 00:13:50 jym Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xen_bus_dma.c,v 1.20 2010/03/09 23:12:06 jym Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -95,6 +95,7 @@
 		xenguest_handle(res.extent_start) = &mfn;
 		res.nr_extents = 1;
 		res.extent_order = 0;
+		res.address_bits = 0;
 		res.domid = DOMID_SELF;
 		error = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &res);
 		if (error != 1) {

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