[Xen-devel] [PATCH 1/3] libxl: attach xen-pciback only to PV domains

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

HVM domains use IOMMU and device model assistance for communicating with
PCI devices, xen-pcifront/pciback is used only in PV domains.
When HVM domain has device model in stubdomain, attaching xen-pciback to
the target domain itself is not only useless, but also may prevent
attaching xen-pciback to the stubdomain, effectively breaking PCI
passthrough.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
---
 tools/libxl/libxl_pci.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/libxl/libxl_pci.c b/tools/libxl/libxl_pci.c
index 6f8f49c..2ae1bc4 100644
--- a/tools/libxl/libxl_pci.c
+++ b/tools/libxl/libxl_pci.c
@@ -1111,7 +1111,7 @@ out:
         }
     }
 
-    if (!starting)
+    if (!starting && !hvm)
         rc = libxl__device_pci_add_xenstore(gc, domid, pcidev, starting);
     else
         rc = 0;
@@ -1306,7 +1306,8 @@ static void libxl__add_pcidevs(libxl__egc *egc, libxl__ao 
*ao, uint32_t domid,
         }
     }
 
-    if (d_config->num_pcidevs > 0) {
+    if (d_config->num_pcidevs > 0
+            && d_config->c_info.type == LIBXL_DOMAIN_TYPE_PV) {
         rc = libxl__create_pci_backend(gc, domid, d_config->pcidevs,
             d_config->num_pcidevs);
         if (rc < 0) {
-- 
2.5.5


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