libxl: passthrough: avoid passing through devices not owned by pciback

This patch makes sure the passthrough device belongs to pciback before
allow them passthrough to the guest.  There are still many other
checks missing.

xm terminates the guest startup process when this type of condition is
found.  This patch just allows the guest to continue to boot but with
no device passthrough.

Signed-off-by: Allen Kay <allen.m.kay@intel.com>
Acked-by: Gianni Tedesco <gianni.tedesco@citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/tools/libxl/libxl_pci.c b/tools/libxl/libxl_pci.c
index 56ec063888..6b5f715e29 100644
--- a/tools/libxl/libxl_pci.c
+++ b/tools/libxl/libxl_pci.c
@@ -763,6 +763,24 @@ int libxl_device_pci_add(libxl_ctx *ctx, uint32_t domid, libxl_device_pci *pcide
     return libxl__device_pci_add(ctx, domid, pcidev, 0);
 }
 
+static int libxl_pcidev_assignable(libxl_ctx *ctx, libxl_device_pci *pcidev)
+{
+    libxl_device_pci *pcidevs;
+    int num, i;
+
+    libxl_device_pci_list_assignable(ctx, &pcidevs, &num);
+    for (i = 0; i < num; i++) {
+        if (pcidevs[i].domain == pcidev->domain &&
+            pcidevs[i].bus == pcidev->bus &&
+            pcidevs[i].dev == pcidev->dev &&
+            pcidevs[i].func == pcidev->func)
+        {
+            return 1;
+        }
+    }
+    return 0;
+}
+
 int libxl__device_pci_add(libxl_ctx *ctx, uint32_t domid, libxl_device_pci *pcidev, int starting)
 {
     libxl__gc gc = LIBXL_INIT_GC(ctx);
@@ -771,6 +789,13 @@ int libxl__device_pci_add(libxl_ctx *ctx, uint32_t domid, libxl_device_pci *pcid
     int num_assigned, i, rc;
     int stubdomid = 0;
 
+    if (!libxl_pcidev_assignable(ctx, pcidev)) {
+        LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "PCI device %x:%x:%x.%x is not assignable",
+                   pcidev->domain, pcidev->bus, pcidev->dev, pcidev->func);
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
     rc = get_all_assigned_devices(&gc, &assigned, &num_assigned);
     if ( rc ) {
         LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "cannot determine if device is assigned, refusing to continue");