[PATCH 4/4] qemu: validate: Prefer existing qemuCaps

[Peter Krempa]

The validation callback always fetched a fresh copy of 'qemuCaps' to use
for validation which is wrong in cases when the VM is already running,
such as device hotplug. The newly-fetched qemuCaps may contain flags
which weren't originally in use when starting the VM e.g. on a libvirtd
upgrade.

Since the post-parse/validation machinery has a per-run 'parseOpaque'
field filled with qemuCaps of the actual process we can reuse the caps
in cases when we get them.

The code still fetches a fresh copy if parseOpaque doesn't have a
per-run copy to preserve existing functionality.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_validate.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
index cb0f830cf1..bf8127a575 100644
--- a/src/qemu/qemu_validate.c
+++ b/src/qemu/qemu_validate.c
@@ -1067,16 +1067,21 @@ qemuValidateDomainDefPanic(const virDomainDef *def,
 int
 qemuValidateDomainDef(const virDomainDef *def,
                       void *opaque,
-                      void *parseOpaque G_GNUC_UNUSED)
+                      void *parseOpaque)
 {
     virQEMUDriverPtr driver = opaque;
     g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
-    g_autoptr(virQEMUCaps) qemuCaps = NULL;
+    g_autoptr(virQEMUCaps) qemuCapsLocal = NULL;
+    virQEMUCapsPtr qemuCaps = parseOpaque;
     size_t i;

-    if (!(qemuCaps = virQEMUCapsCacheLookup(driver->qemuCapsCache,
-                                            def->emulator)))
-        return -1;
+    if (!qemuCaps) {
+        if (!(qemuCapsLocal = virQEMUCapsCacheLookup(driver->qemuCapsCache,
+                                                     def->emulator)))
+            return -1;
+
+        qemuCaps = qemuCapsLocal;
+    }

     if (def->os.type != VIR_DOMAIN_OSTYPE_HVM) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
@@ -4666,15 +4671,20 @@ int
 qemuValidateDomainDeviceDef(const virDomainDeviceDef *dev,
                             const virDomainDef *def,
                             void *opaque,
-                            void *parseOpaque G_GNUC_UNUSED)
+                            void *parseOpaque)
 {
     int ret = 0;
     virQEMUDriverPtr driver = opaque;
-    g_autoptr(virQEMUCaps) qemuCaps = NULL;
+    g_autoptr(virQEMUCaps) qemuCapsLocal = NULL;
+    virQEMUCapsPtr qemuCaps = parseOpaque;

-    if (!(qemuCaps = virQEMUCapsCacheLookup(driver->qemuCapsCache,
-                                            def->emulator)))
-        return -1;
+    if (!qemuCaps) {
+        if (!(qemuCapsLocal = virQEMUCapsCacheLookup(driver->qemuCapsCache,
+                                                     def->emulator)))
+            return -1;
+
+        qemuCaps = qemuCapsLocal;
+    }

     if ((ret = qemuValidateDomainDeviceDefAddress(dev, qemuCaps)) < 0)
         return ret;
-- 
2.28.0