[libvirt] [PATCH] qemu: add qemu.conf option to disable PCI passthrough

[Ján Tomko]

---

Note: virPCIProbeStubDriver is currently broken because of 2f8babc,
I've sent a fix:
https://www.redhat.com/archives/libvir-list/2013-July/msg01154.html

 src/qemu/libvirtd_qemu.aug         | 1 +
 src/qemu/qemu.conf                 | 5 +++++
 src/qemu/qemu_conf.c               | 2 ++
 src/qemu/qemu_conf.h               | 2 ++
 src/qemu/qemu_hostdev.c            | 8 ++++++++
 src/qemu/test_libvirtd_qemu.aug.in | 1 +
 6 files changed, 19 insertions(+)

diff --git a/src/qemu/libvirtd_qemu.aug b/src/qemu/libvirtd_qemu.aug
index 5344125..62399fa 100644
--- a/src/qemu/libvirtd_qemu.aug
+++ b/src/qemu/libvirtd_qemu.aug
@@ -53,6 +53,7 @@ module Libvirtd_qemu =
                  | str_array_entry "cgroup_controllers"
                  | str_array_entry "cgroup_device_acl"
                  | int_entry "seccomp_sandbox"
+                 | bool_entry "pci_passthrough"
 
    let save_entry =  str_entry "save_image_format"
                  | str_entry "dump_image_format"
diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf
index cdf1ec4..23d63d1 100644
--- a/src/qemu/qemu.conf
+++ b/src/qemu/qemu.conf
@@ -212,6 +212,11 @@
 # Set to 0 to disable file ownership changes.
 #dynamic_ownership = 1
 
+# Whether PCI passthrough is enabled.
+# Set to 0 to disable PCI passthrough.
+#
+#pci_passthrough = 1
+
 
 # What cgroup controllers to make use of with QEMU guests
 #
diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index c91551f..fbfff66 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -132,6 +132,7 @@ virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged)
         cfg->group = (gid_t)-1;
     }
     cfg->dynamicOwnership = privileged;
+    cfg->pciPassthrough = true;
 
     cfg->cgroupControllers = -1; /* -1 == auto-detect */
 
@@ -547,6 +548,7 @@ int virQEMUDriverConfigLoadFile(virQEMUDriverConfigPtr cfg,
     GET_VALUE_LONG("keepalive_count", cfg->keepAliveCount);
 
     GET_VALUE_LONG("seccomp_sandbox", cfg->seccompSandbox);
+    GET_VALUE_BOOL("pci_passthrough", cfg->pciPassthrough);
 
     ret = 0;
 
diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
index 19893c8..b12c011 100644
--- a/src/qemu/qemu_conf.h
+++ b/src/qemu/qemu_conf.h
@@ -156,6 +156,8 @@ struct _virQEMUDriverConfig {
     unsigned int keepAliveCount;
 
     int seccompSandbox;
+
+    bool pciPassthrough;
 };
 
 /* Main driver state */
diff --git a/src/qemu/qemu_hostdev.c b/src/qemu/qemu_hostdev.c
index 21fe47f..1916ad1 100644
--- a/src/qemu/qemu_hostdev.c
+++ b/src/qemu/qemu_hostdev.c
@@ -492,6 +492,14 @@ int qemuPrepareHostdevPCIDevices(virQEMUDriverPtr driver,
     if (!(pcidevs = qemuGetPciHostDeviceList(hostdevs, nhostdevs)))
         goto cleanup;
 
+    if (virPCIDeviceListCount(pcidevs) > 0 &&
+        !cfg->pciPassthrough) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       _("PCI passthrough is disabled in qemu.conf"
+                         " but host PCI devices are present"));
+        goto cleanup;
+    }
+
     /* We have to use 9 loops here. *All* devices must
      * be detached before we reset any of them, because
      * in some cases you have to reset the whole PCI,
diff --git a/src/qemu/test_libvirtd_qemu.aug.in b/src/qemu/test_libvirtd_qemu.aug.in
index d4e4fae..f251616 100644
--- a/src/qemu/test_libvirtd_qemu.aug.in
+++ b/src/qemu/test_libvirtd_qemu.aug.in
@@ -25,6 +25,7 @@ module Test_libvirtd_qemu =
 { "user" = "root" }
 { "group" = "root" }
 { "dynamic_ownership" = "1" }
+{ "pci_passthrough" = "1" }
 { "cgroup_controllers"
     { "1" = "cpu" }
     { "2" = "devices" }
-- 
1.8.1.5