From: Keir Fraser <keir.fraser@citrix.com>
Date: Tue, 21 Apr 2009 15:31:26 +0000 (+0100)
Subject: intel vtd: Remove the BUG_ON in domain_context_mapping().
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~13963
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=946a02890ce9adf18da2abc45f93f055732f9318;p=xen.git

intel vtd: Remove the BUG_ON in domain_context_mapping().

Signed-off-by: Dexuan Cui <dexuan.cui@intel.com>
---

diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index dc18b3fde5..ff56a19b36 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1196,7 +1196,20 @@ static int domain_context_mapping(struct domain *domain, u8 bus, u8 devfn)
     u8 secbus, secdevfn;
     struct pci_dev *pdev = pci_get_pdev(bus, devfn);
 
-    BUG_ON(!pdev);
+    if ( pdev == NULL )
+    {
+        /* We can reach here by setup_dom0_rmrr() -> iommu_prepare_rmrr_dev()
+         * -> domain_context_mapping().
+         * In the case a user enables VT-d and disables USB (that usually needs
+         * RMRR) in BIOS, we can't discover the BDF of the USB controller in
+         * setup_dom0_devices(), but the ACPI RMRR structures may still contain
+         * the BDF and at last pci_get_pdev() returns NULL here.
+         */
+        gdprintk(XENLOG_WARNING VTDPREFIX,
+                "domain_context_mapping: can't find bdf = %x:%x.%x\n",
+                 bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
+        return 0;
+    }
 
     drhd = acpi_find_matched_drhd_unit(pdev);
     if ( !drhd )