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

[Peter Zijlstra <peterz@infradead.org>]

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.

> +		printk (KERN_WARNING PREFIX "Zero: Invalid DMAR haw\n");
> +		return -EINVAL;
> +	}
> +
> +	printk (KERN_INFO PREFIX "Host address width %d\n",
> +		dmar->width + 1);
> +
> +	entry_header = (struct acpi_dmar_header *)(dmar + 1);
> +	while (((unsigned long)entry_header) <
> +			(((unsigned long)dmar) + dmar_tbl->length)) {
> +		dmar_table_print_dmar_entry(entry_header);
> +
> +		switch (entry_header->type) {
> +		case ACPI_DMAR_TYPE_HARDWARE_UNIT:
> +			ret = dmar_parse_one_drhd(entry_header);
> +			break;
> +		case ACPI_DMAR_TYPE_RESERVED_MEMORY:
> +			ret = dmar_parse_one_rmrr(entry_header);
> +			break;
> +		default:
> +			printk(KERN_WARNING PREFIX
> +				"Unknown DMAR structure type\n");
> +			ret = 0; /* for forward compatibility */
> +			break;
> +		}
> +		if (ret)
> +			break;
> +
> +		entry_header = ((void *)entry_header + entry_header->length);
> +	}
> +	return ret;
> +}
> +