[libvirt PATCH v2 1/5] add QEMU_CAPS_TCG_DISABLED and probe conditionally

[Tobin Feldman-Fitzthum <tobin@xxxxxxxxxxxxxxxxxx>]

Only probe QEMU binary with accel=tcg if TCG is not disabled.
Similarly, only add a VIR_DOMAIN_VIRT_QEMU guest if TCG
is available.

Signed-off-by: Tobin Feldman-Fitzthum <tobin@xxxxxxxxxxxxxxxxxx>
---
 src/qemu/qemu_capabilities.c | 22 ++++++++++++++--------
 src/qemu/qemu_capabilities.h |  1 +
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index a95a60c36a..61123f0e63 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -567,6 +567,7 @@ VIR_ENUM_IMPL(virQEMUCaps,
               "query-named-block-nodes.flat",
               "blockdev-snapshot.allow-write-only-overlay",
               "blockdev-reopen",
+              "tcg-disabled",
     );
 
 
@@ -1008,13 +1009,16 @@ virQEMUCapsInitGuestFromBinary(virCapsPtr caps,
     virCapabilitiesAddGuestFeatureWithToggle(guest, VIR_CAPS_GUEST_FEATURE_TYPE_DISKSNAPSHOT,
                                              true, false);
 
-    if (virCapabilitiesAddGuestDomain(guest,
-                                      VIR_DOMAIN_VIRT_QEMU,
-                                      NULL,
-                                      NULL,
-                                      0,
-                                      NULL) == NULL)
-        goto cleanup;
+    if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_TCG_DISABLED)) {
+        if (virCapabilitiesAddGuestDomain(guest,
+                                          VIR_DOMAIN_VIRT_QEMU,
+                                          NULL,
+                                          NULL,
+                                          0,
+                                          NULL) == NULL) {
+            goto cleanup;
+        }
+    }
 
     if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_KVM)) {
         if (virCapabilitiesAddGuestDomain(guest,
@@ -2274,7 +2278,8 @@ bool
 virQEMUCapsIsVirtTypeSupported(virQEMUCapsPtr qemuCaps,
                                virDomainVirtType virtType)
 {
-    if (virtType == VIR_DOMAIN_VIRT_QEMU)
+    if (virtType == VIR_DOMAIN_VIRT_QEMU &&
+        !virQEMUCapsGet(qemuCaps, QEMU_CAPS_TCG_DISABLED))
         return true;
 
     if (virtType == VIR_DOMAIN_VIRT_KVM &&
@@ -5123,6 +5128,7 @@ virQEMUCapsInitQMP(virQEMUCapsPtr qemuCaps,
      * off.
      */
     if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_KVM) &&
+        !virQEMUCapsGet(qemuCaps, QEMU_CAPS_TCG_DISABLED) &&
         virQEMUCapsInitQMPSingle(qemuCaps, libDir, runUid, runGid, true) < 0)
         return -1;
 
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index f0961e273c..372806f585 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -548,6 +548,7 @@ typedef enum { /* virQEMUCapsFlags grouping marker for syntax-check */
     QEMU_CAPS_QMP_QUERY_NAMED_BLOCK_NODES_FLAT, /* query-named-block-nodes supports the 'flat' option */
     QEMU_CAPS_BLOCKDEV_SNAPSHOT_ALLOW_WRITE_ONLY, /* blockdev-snapshot has the 'allow-write-only-overlay' feature */
     QEMU_CAPS_BLOCKDEV_REOPEN, /* 'blockdev-reopen' qmp command is supported */
+    QEMU_CAPS_TCG_DISABLED, /* QEMU does not support TCG */
 
     QEMU_CAPS_LAST /* this must always be the last item */
 } virQEMUCapsFlags;
-- 
2.20.1 (Apple Git-117)