Re: [Intel IOMMU 01/10] DMAR detection and parsing logic

[Andrew Morton]

On Wed, 04 Jul 2007 11:18:56 +0200 Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Tue, 2007-06-19 at 14:37 -0700, Keshavamurthy, Anil S wrote:
> > plain text document attachment (dmar_detection.patch)
> 
> > +/**
> > + * parse_dmar_table - parses the DMA reporting table
> > + */
> > +static int __init
> > +parse_dmar_table(void)
> > +{
> > +	struct acpi_table_dmar *dmar;
> > +	struct acpi_dmar_header *entry_header;
> > +	int ret = 0;
> > +
> > +	dmar = (struct acpi_table_dmar *)dmar_tbl;
> > +
> > +	if (!dmar->width) {
>           ^^^^^^^^^^^^^^^^^^^
> 
> That goes *splat* on my opteron box.

This?

From: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@xxxxxxxxx>

Check for dmar_tbl pointer as this can be NULL on systems with no Intel
VT-d support.

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 drivers/pci/dmar.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff -puN drivers/pci/dmar.c~intel-iommu-dmar-detection-and-parsing-logic-fix-intel-dmar-crash-on-amd-x86_64 drivers/pci/dmar.c
--- a/drivers/pci/dmar.c~intel-iommu-dmar-detection-and-parsing-logic-fix-intel-dmar-crash-on-amd-x86_64
+++ a/drivers/pci/dmar.c
@@ -260,6 +260,8 @@ parse_dmar_table(void)
 	int ret = 0;
 
 	dmar = (struct acpi_table_dmar *)dmar_tbl;
+	if (!dmar)
+		return -ENODEV;
 
 	if (!dmar->width) {
 		printk (KERN_WARNING PREFIX "Zero: Invalid DMAR haw\n");
@@ -301,7 +303,7 @@ int __init dmar_table_init(void)
 
 	parse_dmar_table();
 	if (list_empty(&dmar_drhd_units)) {
-		printk(KERN_ERR PREFIX "No DMAR devices found\n");
+		printk(KERN_INFO PREFIX "No DMAR devices found\n");
 		return -ENODEV;
 	}
 	return 0;
_

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