Author: emaste
Date: Thu Mar 1 19:43:28 2012
New Revision: 232354
URL: http://svn.freebsd.org/changeset/base/232354
Log:
MFC r232267:
Workaround for PCIe 4GB boundary issue
Enforce a boundary of no more than 4GB - transfers crossing a 4GB
boundary can lead to data corruption due to PCIe limitations. This
change is a less-intrusive workaround that can be quickly merged back
to older branches; a cleaner implementation will arrive in HEAD later
but may require KPI changes.
This change is based on a suggestion by jhb@.
Approved by: re
Reviewed by: jhb (MFC)
Reviewed by: jhb, scottl (original)
Sponsored by: Sandvine Incorporated
Modified:
stable/8/sys/amd64/amd64/busdma_machdep.c
stable/8/sys/i386/i386/busdma_machdep.c
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/amd64/include/xen/ (props changed)
stable/8/sys/boot/ (props changed)
stable/8/sys/cddl/contrib/opensolaris/ (props changed)
stable/8/sys/contrib/dev/acpica/ (props changed)
stable/8/sys/contrib/pf/ (props changed)
stable/8/sys/dev/e1000/ (props changed)
stable/8/sys/i386/conf/XENHVM (props changed)
Modified: stable/8/sys/amd64/amd64/busdma_machdep.c
==============================================================================
--- stable/8/sys/amd64/amd64/busdma_machdep.c Thu Mar 1 19:17:56 2012
(r232353)
+++ stable/8/sys/amd64/amd64/busdma_machdep.c Thu Mar 1 19:43:28 2012
(r232354)
@@ -216,6 +216,10 @@ bus_dma_tag_create(bus_dma_tag_t parent,
bus_dma_tag_t newtag;
int error = 0;
+ /* Always enforce at least a 4GB boundary. */
+ if (boundary == 0 || boundary > ((bus_addr_t)1 << 32))
+ boundary = (bus_size_t)1 << 32;
+
/* Basic sanity checking */
if (boundary != 0 && boundary < maxsegsz)
maxsegsz = boundary;
Modified: stable/8/sys/i386/i386/busdma_machdep.c
==============================================================================
--- stable/8/sys/i386/i386/busdma_machdep.c Thu Mar 1 19:17:56 2012
(r232353)
+++ stable/8/sys/i386/i386/busdma_machdep.c Thu Mar 1 19:43:28 2012
(r232354)
@@ -226,6 +226,12 @@ bus_dma_tag_create(bus_dma_tag_t parent,
bus_dma_tag_t newtag;
int error = 0;
+#if defined(PAE)
+ /* Need at least a 4GB boundary, PAE limitations require 2GB */
+ if (boundary == 0 || boundary > ((bus_addr_t)1 << 31))
+ boundary = (bus_size_t)1 << 31;
+#endif
+
/* Basic sanity checking */
if (boundary != 0 && boundary < maxsegsz)
maxsegsz = boundary;
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