[Libvirt-cim] [PATCH V3 1/3] add an config option to disable KVM acceleration

[cngesaint at outlook.com]

From: Wenchao Xia <xiawenc at linux.vnet.ibm.com>

Since libvirt-cim doesn't handle nested KVM well now, so add this
option to manually disable KVM and fall back to qemu.

Signed-off-by: Xu Wang <cngesaint at outlook.com>
---
 libvirt-cim.conf                          |    9 +++++++++
 libxkutil/misc_util.c                     |    8 ++++++++
 libxkutil/misc_util.h                     |    1 +
 src/Virt_VirtualSystemManagementService.c |    7 +++++++
 4 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/libvirt-cim.conf b/libvirt-cim.conf
index 37d7b0f..f6464c3 100644
--- a/libvirt-cim.conf
+++ b/libvirt-cim.conf
@@ -30,3 +30,12 @@
 #  Default value: NULL, that is not set.
 #
 # migrate_ssh_temp_key = "/root/vm_migrate_tmp_id_rsa";
+
+# disable_kvm (bool)
+#  When executing in a nested KVM environment libvirt-cim may fail
+#  unexpectedly with some error. Setting "disable_kvm" option to true
+#  disables use of KVM and falls back to using QEMU directly.
+#  Possible values: {true,false}
+#  Default value: false
+#
+# disable_kvm = false;
diff --git a/libxkutil/misc_util.c b/libxkutil/misc_util.c
index 00eb4b1..921604c 100644
--- a/libxkutil/misc_util.c
+++ b/libxkutil/misc_util.c
@@ -227,6 +227,14 @@ static int is_read_only(void)
         return prop.value_bool;
 }
 
+bool get_disable_kvm(void)
+{
+        static LibvirtcimConfigProperty prop = {
+                                       "disable_kvm", CONFIG_BOOL, {0}, 0};
+        libvirt_cim_config_get(&prop);
+        return prop.value_bool;
+}
+
 const char *get_mig_ssh_tmp_key(void)
 {
         static LibvirtcimConfigProperty prop = {
diff --git a/libxkutil/misc_util.h b/libxkutil/misc_util.h
index 0f52290..8493005 100644
--- a/libxkutil/misc_util.h
+++ b/libxkutil/misc_util.h
@@ -154,6 +154,7 @@ int virt_set_status(const CMPIBroker *broker,
 
 /* get libvirt-cim config */
 const char *get_mig_ssh_tmp_key(void);
+bool get_disable_kvm(void);
 
 /*
  * Local Variables:
diff --git a/src/Virt_VirtualSystemManagementService.c b/src/Virt_VirtualSystemManagementService.c
index cbb646d..1369c6a 100644
--- a/src/Virt_VirtualSystemManagementService.c
+++ b/src/Virt_VirtualSystemManagementService.c
@@ -394,6 +394,13 @@ static bool system_has_kvm(const char *pfx)
         virConnectPtr conn;
         char *caps = NULL;
         bool kvm = false;
+        bool disable_kvm = get_disable_kvm();
+
+        /* sometimes disable KVM to avoid problem in nested KVM */
+        if (disable_kvm) {
+                CU_DEBUG("Enter disable kvm mode!");
+                return false;
+        }
 
         conn = connect_by_classname(_BROKER, pfx, &s);
         if ((conn == NULL) || (s.rc != CMPI_RC_OK)) {
-- 
1.7.1