AMD IOMMU: fix Dom0 device setup failure for host bridges

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@amd.com>
Reported-by: Stefan Bader <stefan.bader@canonical.com>

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

Coding style cleanup.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Xiantao Zhang <xiantao.zhang@intel.com>

5 files changed, 37 insertions, 5 deletions

diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c b/xen/drivers/passthrough/amd/pci_amd_iommu.c
index 9684ae8cfe..7241aad459 100644
--- 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_device(
 
         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_device(u8 devfn, struct pci_dev *pdev)
 
     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));
diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index e9f2a56dbc..4aa8f64255 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -194,9 +194,6 @@ static struct pci_dev *alloc_pdev(struct pci_seg *pseg, u8 bus, u8 devfn)
         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 pci_seg *pseg, u8 bus, u8 devfn)
             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 *d)
     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, u8 devfn)
             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;
diff --git a/xen/drivers/passthrough/vtd/intremap.c b/xen/drivers/passthrough/vtd/intremap.c
index f3bb31b4b2..2f8b9ebc23 100644
--- 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_dev *pdev, struct iremap_entry *ire)
     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;
diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index fd3abcbcef..12e0165665 100644
--- 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:
diff --git a/xen/include/xen/pci.h b/xen/include/xen/pci.h
index 3003803af6..cadb525ec6 100644
--- 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;