Tue Mar 9 23:12:06 2010 UTC ()
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 haad@.

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


(jym)
diff -r1.19 -r1.20 src/sys/arch/xen/x86/xen_bus_dma.c
cvs diff -r1.19 -r1.20 src/sys/arch/xen/x86/xen_bus_dma.c (expand / switch to unified diff)

--- src/sys/arch/xen/x86/xen_bus_dma.c 2010/03/02 00:13:50 1.19
+++ src/sys/arch/xen/x86/xen_bus_dma.c 2010/03/09 23:12:06 1.20
@@ -1,14 +1,14 @@ @@ -1,14 +1,14 @@
1/* $NetBSD: xen_bus_dma.c,v 1.19 2010/03/02 00:13:50 jym Exp $ */ 1/* $NetBSD: xen_bus_dma.c,v 1.20 2010/03/09 23:12:06 jym Exp $ */
2/* NetBSD bus_dma.c,v 1.21 2005/04/16 07:53:35 yamt Exp */ 2/* NetBSD bus_dma.c,v 1.21 2005/04/16 07:53:35 yamt Exp */
3 3
4/*- 4/*-
5 * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc. 5 * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
6 * All rights reserved. 6 * All rights reserved.
7 * 7 *
8 * This code is derived from software contributed to The NetBSD Foundation 8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Charles M. Hannum and by Jason R. Thorpe of the Numerical Aerospace 9 * by Charles M. Hannum and by Jason R. Thorpe of the Numerical Aerospace
10 * Simulation Facility, NASA Ames Research Center. 10 * Simulation Facility, NASA Ames Research Center.
11 * 11 *
12 * Redistribution and use in source and binary forms, with or without 12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions 13 * modification, are permitted provided that the following conditions
14 * are met: 14 * are met:
@@ -22,27 +22,27 @@ @@ -22,27 +22,27 @@
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE. 31 * POSSIBILITY OF SUCH DAMAGE.
32 */ 32 */
33 33
34#include <sys/cdefs.h> 34#include <sys/cdefs.h>
35__KERNEL_RCSID(0, "$NetBSD: xen_bus_dma.c,v 1.19 2010/03/02 00:13:50 jym Exp $"); 35__KERNEL_RCSID(0, "$NetBSD: xen_bus_dma.c,v 1.20 2010/03/09 23:12:06 jym Exp $");
36 36
37#include <sys/param.h> 37#include <sys/param.h>
38#include <sys/systm.h> 38#include <sys/systm.h>
39#include <sys/kernel.h> 39#include <sys/kernel.h>
40#include <sys/mbuf.h> 40#include <sys/mbuf.h>
41#include <sys/proc.h> 41#include <sys/proc.h>
42 42
43#include <machine/bus.h> 43#include <machine/bus.h>
44#include <machine/bus_private.h> 44#include <machine/bus_private.h>
45 45
46#include <uvm/uvm_extern.h> 46#include <uvm/uvm_extern.h>
47 47
48extern paddr_t avail_end; 48extern paddr_t avail_end;
@@ -85,26 +85,27 @@ _xen_alloc_contig(bus_size_t size, bus_s @@ -85,26 +85,27 @@ _xen_alloc_contig(bus_size_t size, bus_s
85 error = uvm_pglistalloc(((psize_t)npages) << PAGE_SHIFT, 85 error = uvm_pglistalloc(((psize_t)npages) << PAGE_SHIFT,
86 0, avail_end, 0, 0, mlistp, npages, (flags & BUS_DMA_NOWAIT) == 0); 86 0, avail_end, 0, 0, mlistp, npages, (flags & BUS_DMA_NOWAIT) == 0);
87 if (error) 87 if (error)
88 return (error); 88 return (error);
89 89
90 for (pg = mlistp->tqh_first; pg != NULL; pg = pg->pageq.queue.tqe_next) { 90 for (pg = mlistp->tqh_first; pg != NULL; pg = pg->pageq.queue.tqe_next) {
91 pa = VM_PAGE_TO_PHYS(pg); 91 pa = VM_PAGE_TO_PHYS(pg);
92 mfn = xpmap_ptom(pa) >> PAGE_SHIFT; 92 mfn = xpmap_ptom(pa) >> PAGE_SHIFT;
93 xpmap_phys_to_machine_mapping[ 93 xpmap_phys_to_machine_mapping[
94 (pa - XPMAP_OFFSET) >> PAGE_SHIFT] = INVALID_P2M_ENTRY; 94 (pa - XPMAP_OFFSET) >> PAGE_SHIFT] = INVALID_P2M_ENTRY;
95 xenguest_handle(res.extent_start) = &mfn; 95 xenguest_handle(res.extent_start) = &mfn;
96 res.nr_extents = 1; 96 res.nr_extents = 1;
97 res.extent_order = 0; 97 res.extent_order = 0;
 98 res.address_bits = 0;
98 res.domid = DOMID_SELF; 99 res.domid = DOMID_SELF;
99 error = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &res); 100 error = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &res);
100 if (error != 1) { 101 if (error != 1) {
101#ifdef DEBUG 102#ifdef DEBUG
102 printf("xen_alloc_contig: XENMEM_decrease_reservation " 103 printf("xen_alloc_contig: XENMEM_decrease_reservation "
103 "failed: err %d (pa %#" PRIxPADDR " mfn %#lx)\n", 104 "failed: err %d (pa %#" PRIxPADDR " mfn %#lx)\n",
104 error, pa, mfn); 105 error, pa, mfn);
105#endif 106#endif
106 xpmap_phys_to_machine_mapping[ 107 xpmap_phys_to_machine_mapping[
107 (pa - XPMAP_OFFSET) >> PAGE_SHIFT] = mfn; 108 (pa - XPMAP_OFFSET) >> PAGE_SHIFT] = mfn;
108 109
109 error = ENOMEM; 110 error = ENOMEM;
110 goto failed; 111 goto failed;