[patch 51/58] intel-iommu: Avoid panic() for DRHD at address zero.

Greg KH
2009-05-06T22:16:44Z

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2.6.29-stable review patch. If anyone has any objections, please let us know.

------------------

From: David Woodhouse <dwmw2@infradead.org>

(cherry picked from commit e523b38e2f568af58baa13120a994cbf24e6dee0)

If the BIOS does something obviously stupid, like claiming that the
registers for the IOMMU are at physical address zero, then print a nasty
message and abort, rather than trying to set up the IOMMU and then later
panicking.

It's becoming more and more obvious that trusting this stuff to the BIOS
was a mistake.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/pci/dmar.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -170,12 +170,21 @@ dmar_parse_one_drhd(struct acpi_dmar_hea
struct dmar_drhd_unit *dmaru;
int ret = 0;

+ drhd = (struct acpi_dmar_hardware_unit *)header;
+ if (!drhd->address) {
+ /* Promote an attitude of violence to a BIOS engineer today */
+ WARN(1, "Your BIOS is broken; DMAR reported at address zero!\n"
+ "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
+ dmi_get_system_info(DMI_BIOS_VENDOR),
+ dmi_get_system_info(DMI_BIOS_VERSION),
+ dmi_get_system_info(DMI_PRODUCT_VERSION));
+ return -ENODEV;
+ }
dmaru = kzalloc(sizeof(*dmaru), GFP_KERNEL);
if (!dmaru)
return -ENOMEM;

dmaru->hdr = header;
- drhd = (struct acpi_dmar_hardware_unit *)header;
dmaru->reg_base_addr = drhd->address;
dmaru->include_all = drhd->flags & 0x1; /* BIT0: INCLUDE_ALL */