[Xen-devel] [PATCH v5] AMD IOMMU: fix Dom0 device setup failure for host bridges

["Jan Beulich" <JBeulich@xxxxxxxx>]

The host bridge device (i.e. 0x18 for AMD) does not require IOMMU, and
therefore is not included in the IVRS. The current logic tries to map
all PCI devices to an IOMMU. In this case, "xl dmesg" shows the
following message on AMD sytem.

(XEN) setup 0000:00:18.0 for d0 failed (-19)
(XEN) setup 0000:00:18.1 for d0 failed (-19)
(XEN) setup 0000:00:18.2 for d0 failed (-19)
(XEN) setup 0000:00:18.3 for d0 failed (-19)
(XEN) setup 0000:00:18.4 for d0 failed (-19)
(XEN) setup 0000:00:18.5 for d0 failed (-19)

This patch adds a new device type (i.e. DEV_TYPE_PCI_HOST_BRIDGE) which
corresponds to PCI class code 0x06 and sub-class 0x00. Then, it uses
this new type to filter when trying to map device to IOMMU.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Reported-by: Stefan Bader <stefan.bader@xxxxxxxxxxxxx>

On VT-d refuse (un)mapping host bridges for other than the hardware
domain.

Coding style cleanup.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -147,9 +147,10 @@ static void amd_iommu_setup_domain_devic
 
         amd_iommu_flush_device(iommu, req_id);
 
-        AMD_IOMMU_DEBUG("Setup I/O page table: device id = %#x, "
+        AMD_IOMMU_DEBUG("Setup I/O page table: device id = %#x, type = %#x, "
                         "root table = %#"PRIx64", "
-                        "domain = %d, paging mode = %d\n", req_id,
+                        "domain = %d, paging mode = %d\n",
+                        req_id, pdev->type,
                         page_to_maddr(hd->root_table),
                         hd->domain_id, hd->paging_mode);
     }
@@ -175,6 +176,15 @@ static int __init amd_iommu_setup_dom0_d
 
     if ( unlikely(!iommu) )
     {
+        /* Filter the bridge devices */
+        if ( pdev->type == DEV_TYPE_PCI_HOST_BRIDGE )
+        {
+            AMD_IOMMU_DEBUG("Skipping host bridge %04x:%02x:%02x.%u\n",
+                            pdev->seg, PCI_BUS(bdf), PCI_SLOT(bdf),
+                            PCI_FUNC(bdf));
+            return 0;
+        }
+
         AMD_IOMMU_DEBUG("No iommu for device %04x:%02x:%02x.%u\n",
                         pdev->seg, pdev->bus,
                         PCI_SLOT(devfn), PCI_FUNC(devfn));
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -194,9 +194,6 @@ static struct pci_dev *alloc_pdev(struct
         u16 cap;
         u8 sec_bus, sub_bus;
 
-        case DEV_TYPE_PCIe_BRIDGE:
-            break;
-
         case DEV_TYPE_PCIe2PCI_BRIDGE:
         case DEV_TYPE_LEGACY_PCI_BRIDGE:
             sec_bus = pci_conf_read8(pseg->nr, bus, PCI_SLOT(devfn),
@@ -244,6 +241,8 @@ static struct pci_dev *alloc_pdev(struct
             break;
 
         case DEV_TYPE_PCI:
+        case DEV_TYPE_PCIe_BRIDGE:
+        case DEV_TYPE_PCI_HOST_BRIDGE:
             break;
 
         default:
@@ -697,6 +696,7 @@ void pci_release_devices(struct domain *
     spin_unlock(&pcidevs_lock);
 }
 
+#define PCI_CLASS_BRIDGE_HOST    0x0600
 #define PCI_CLASS_BRIDGE_PCI     0x0604
 
 enum pdev_type pdev_type(u16 seg, u8 bus, u8 devfn)
@@ -720,6 +720,8 @@ enum pdev_type pdev_type(u16 seg, u8 bus
             return DEV_TYPE_PCI2PCIe_BRIDGE;
         }
         return DEV_TYPE_PCIe_BRIDGE;
+    case PCI_CLASS_BRIDGE_HOST:
+        return DEV_TYPE_PCI_HOST_BRIDGE;
 
     case 0x0000: case 0xffff:
         return DEV_TYPE_PCI_UNKNOWN;
--- a/xen/drivers/passthrough/vtd/intremap.c
+++ b/xen/drivers/passthrough/vtd/intremap.c
@@ -442,6 +442,7 @@ static void set_msi_source_id(struct pci
     case DEV_TYPE_PCIe_ENDPOINT:
     case DEV_TYPE_PCIe_BRIDGE:
     case DEV_TYPE_PCIe2PCI_BRIDGE:
+    case DEV_TYPE_PCI_HOST_BRIDGE:
         switch ( pdev->phantom_stride )
         {
         case 1: sq = SQ_13_IGNORE_3; break;
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1433,6 +1433,15 @@ static int domain_context_mapping(
 
     switch ( pdev->type )
     {
+    case DEV_TYPE_PCI_HOST_BRIDGE:
+        if ( iommu_verbose )
+            dprintk(VTDPREFIX, "d%d:Hostbridge: skip %04x:%02x:%02x.%u map\n",
+                    domain->domain_id, seg, bus,
+                    PCI_SLOT(devfn), PCI_FUNC(devfn));
+        if ( !is_hardware_domain(domain) )
+            return -EPERM;
+        break;
+
     case DEV_TYPE_PCIe_BRIDGE:
     case DEV_TYPE_PCIe2PCI_BRIDGE:
     case DEV_TYPE_LEGACY_PCI_BRIDGE:
@@ -1563,6 +1572,15 @@ static int domain_context_unmap(
 
     switch ( pdev->type )
     {
+    case DEV_TYPE_PCI_HOST_BRIDGE:
+        if ( iommu_verbose )
+            dprintk(VTDPREFIX, "d%d:Hostbridge: skip %04x:%02x:%02x.%u 
unmap\n",
+                    domain->domain_id, seg, bus,
+                    PCI_SLOT(devfn), PCI_FUNC(devfn));
+        if ( !is_hardware_domain(domain) )
+            return -EPERM;
+        goto out;
+
     case DEV_TYPE_PCIe_BRIDGE:
     case DEV_TYPE_PCIe2PCI_BRIDGE:
     case DEV_TYPE_LEGACY_PCI_BRIDGE:
--- a/xen/include/xen/pci.h
+++ b/xen/include/xen/pci.h
@@ -63,6 +63,7 @@ struct pci_dev {
         DEV_TYPE_PCIe2PCI_BRIDGE,   // PCIe-to-PCI/PCIx bridge
         DEV_TYPE_PCI2PCIe_BRIDGE,   // PCI/PCIx-to-PCIe bridge
         DEV_TYPE_LEGACY_PCI_BRIDGE, // Legacy PCI bridge
+        DEV_TYPE_PCI_HOST_BRIDGE,   // PCI Host bridge
         DEV_TYPE_PCI,
     } type;

Attachment: AMD-IOMMU-suppress-hostbridge-setup.patch
Description: Text document

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel