intel-iommu: Check for an RMRR which ends before it starts.

commit 5595b528b49a702c0428c0762bab60999648254c upstream.

Some HP BIOSes report an RMRR region (a region which needs a 1:1 mapping
in the IOMMU for a given device) which has an end address lower than its
start address. Detect that and warn, rather than triggering the
BUG() in dma_pte_clear_range().

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

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 1840a0578a429366874ca049d05af748a1f88c09..1db5b037edbc3bdb66cc2b0891a38c65c79ac906 100644 (file)
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -1991,6 +1991,16 @@ static int iommu_prepare_identity_map(struct pci_dev *pdev,
               "IOMMU: Setting identity map for device %s [0x%Lx - 0x%Lx]\n",
               pci_name(pdev), start, end);
        
+       if (end < start) {
+               WARN(1, "Your BIOS is broken; RMRR ends before it starts!\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));
+               ret = -EIO;
+               goto error;
+       }
+
        if (end >> agaw_to_width(domain->agaw)) {
                WARN(1, "Your BIOS is broken; RMRR exceeds permitted address width (%d bits)\n"
                     "BIOS vendor: %s; Ver: %s; Product Version: %s\n",