1.1 --- a/xen/drivers/passthrough/vtd/iommu.c	Tue Apr 21 18:27:59 2009 +0900
     1.2 +++ b/xen/drivers/passthrough/vtd/iommu.c	Tue Apr 21 16:31:26 2009 +0100
     1.3 @@ -1196,7 +1196,20 @@ static int domain_context_mapping(struct
     1.4      u8 secbus, secdevfn;
     1.5      struct pci_dev *pdev = pci_get_pdev(bus, devfn);
     1.6  
     1.7 -    BUG_ON(!pdev);
     1.8 +    if ( pdev == NULL )
     1.9 +    {
    1.10 +        /* We can reach here by setup_dom0_rmrr() -> iommu_prepare_rmrr_dev()
    1.11 +         * -> domain_context_mapping().
    1.12 +         * In the case a user enables VT-d and disables USB (that usually needs
    1.13 +         * RMRR) in BIOS, we can't discover the BDF of the USB controller in
    1.14 +         * setup_dom0_devices(), but the ACPI RMRR structures may still contain
    1.15 +         * the BDF and at last pci_get_pdev() returns NULL here.
    1.16 +         */
    1.17 +        gdprintk(XENLOG_WARNING VTDPREFIX,
    1.18 +                "domain_context_mapping: can't find bdf = %x:%x.%x\n",
    1.19 +                 bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
    1.20 +        return 0;
    1.21 +    }
    1.22  
    1.23      drhd = acpi_find_matched_drhd_unit(pdev);
    1.24      if ( !drhd )