[libvirt] [PATCH v2] util: disallow assigning or resetting a pci-bridge device

[Shivaprasad G Bhat]

It is destructive to attempt reset on a pci-bridge, the host can crash.
The bridges won't contain any guest data and neither they can be
passed through using vfio/stub. So, no point in allowing a reset on them.

Signed-off-by: Shivaprasad G Bhat <sbhat at linux.vnet.ibm.com>
---
 src/util/virhostdev.c |   10 ++++++++++
 src/util/virpci.c     |   11 +++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/util/virhostdev.c b/src/util/virhostdev.c
index 0673afb..16b96f3 100644
--- a/src/util/virhostdev.c
+++ b/src/util/virhostdev.c
@@ -532,6 +532,16 @@ virHostdevPreparePCIDevices(virHostdevManagerPtr mgr,
         bool strict_acs_check = !!(flags & VIR_HOSTDEV_STRICT_ACS_CHECK);
         bool usesVFIO = (virPCIDeviceGetStubDriver(pci) == VIR_PCI_STUB_DRIVER_VFIO);
         struct virHostdevIsPCINodeDeviceUsedData data = { mgr, dom_name, usesVFIO };
+        int hdrType = -1;
+
+        if (virPCIGetHeaderType(pci, &hdrType) < 0)
+            goto cleanup;
+
+        if (hdrType == VIR_PCI_HEADER_PCI_BRIDGE) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("PCI bridge devices"
+                           " cannot be assigned to guests"));
+            goto cleanup;
+        }
 
         if (!usesVFIO && !virPCIDeviceIsAssignable(pci, strict_acs_check)) {
             virReportError(VIR_ERR_OPERATION_INVALID,
diff --git a/src/util/virpci.c b/src/util/virpci.c
index 0601f49..f205abf 100644
--- a/src/util/virpci.c
+++ b/src/util/virpci.c
@@ -933,6 +933,17 @@ virPCIDeviceReset(virPCIDevicePtr dev,
     char *drvName = NULL;
     int ret = -1;
     int fd = -1;
+    int hdrType = -1;
+
+    if (virPCIGetHeaderType(dev, &hdrType) < 0)
+        return -1;
+
+    if (hdrType != VIR_PCI_HEADER_ENDPOINT) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Invalid attempt to reset non-endpoint PCI device %s."
+                         " Only PCI endpoint devices can be reset"), dev->name);
+        return -1;
+    }
 
     if (activeDevs && virPCIDeviceListFind(activeDevs, dev)) {
         virReportError(VIR_ERR_INTERNAL_ERROR,