zfs-aarch64/centos-9/SOURCES/libvirt-qemu-Allow-reuse-of-qemuProcessStartUpdateCustomCaps.patch

From 8ceddabb12d1b32fbcffe9697885462af133d309 Mon Sep 17 00:00:00 2001
Message-ID: <8ceddabb12d1b32fbcffe9697885462af133d309.1784297531.git.jdenemar@redhat.com>
From: Peter Krempa <pkrempa@redhat.com>
Date: Thu, 11 Jun 2026 12:00:45 +0200
Subject: [PATCH] qemu: Allow reuse of 'qemuProcessStartUpdateCustomCaps'

Move and rename the function to 'qemuDomainUpdateCustomCapabilities' and
modify the arguments so that it will be possible to reuse it also in the
post-parse and validation code which ought to base decisions on the same
logic as VM startup would.

Since copying of the qemu capabilities object is very expensive (I've
observed an almost 4x slowdown of qemuxmlconftest)
'qemuDomainUpdateCustomCapabilities' copies the capabilities only when
necessary.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
(cherry picked from commit 9ec26e2c4f7c60a1ba62a90948a51a7ac0f582d8)

https://redhat.atlassian.net/browse/RHEL-186019

https://redhat.atlassian.net/browse/RHEL-177646 (rhel-9.9)
---
 src/qemu/qemu_domain.c  | 79 +++++++++++++++++++++++++++++++++++++++++
 src/qemu/qemu_domain.h  |  6 ++++
 src/qemu/qemu_process.c | 42 +---------------------
 3 files changed, 86 insertions(+), 41 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 495cbd4f7d..7699d1000f 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -11769,3 +11769,82 @@ qemuDomainMachineSupportsFloppy(const char *machine,
 
     return true;
 }
+
+
+/**
+ * qemuDomainUpdateCustomCapabilities:
+ * @def: domain definition
+ * @qemuCaps: qemu capabilities
+ * @qemuCapsCopy: if non-NULL filled filled with a valid virQEMUCaps pointer (see below)
+ *
+ * Updates @qemuCaps based on the qemu namespace XML config for modifying
+ * capabilities:
+ *
+ *  <domain type='qemu' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
+ *    <qemu:capabilities>
+ *      <qemu:add capability='blockdev'/>
+ *      <qemu:del capability='drive'/>
+ *    </qemu:capabilities>
+ *  </domain>
+ *
+ *  If @qemuCapsCopy is NULL, @qemuCaps is directly modified.
+ *
+ *  If @qemuCapsCopy is non-NULL, it's always filled with a virQEMUCaps instance
+ *  that the caller needs to unref. The following applies:
+ *   - no caps modification needed: @qemuCaps is ref'd and filled into @qemuCapsCopy
+ *   - caps modifications are needed: @qemuCaps is copied into @qemuCapsCopy and
+ *                                    modifications happen on the copy
+ *
+ *  Returns 0 on success (including when no modification was needed), -1 on
+ *  error and reports libvirt errors.
+ */
+int
+qemuDomainUpdateCustomCapabilities(const virDomainDef *def,
+                                   virQEMUCaps *qemuCaps,
+                                   virQEMUCaps **qemuCapsCopy)
+{
+    qemuDomainXmlNsDef *nsdef = def->namespaceData;
+    char **next;
+    int tmp;
+
+    if (!nsdef ||
+        (!nsdef->capsadd && !nsdef->capsdel)) {
+
+        if (qemuCapsCopy)
+            *qemuCapsCopy = virObjectRef(qemuCaps);
+
+        return 0;
+    }
+
+    if (qemuCapsCopy) {
+        *qemuCapsCopy = virQEMUCapsNewCopy(qemuCaps);
+
+        qemuCaps = *qemuCapsCopy;
+    }
+
+    for (next = nsdef->capsadd; next && *next; next++) {
+        if ((tmp = virQEMUCapsTypeFromString(*next)) < 0) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("invalid qemu namespace capability '%1$s'"),
+                           *next);
+            return -1;
+        }
+
+        virQEMUCapsSet(qemuCaps, tmp);
+    }
+
+    for (next = nsdef->capsdel; next && *next; next++) {
+        if ((tmp = virQEMUCapsTypeFromString(*next)) < 0) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("invalid qemu namespace capability '%1$s'"),
+                           *next);
+            return -1;
+        }
+
+        virQEMUCapsClear(qemuCaps, tmp);
+    }
+
+    virQEMUCapsInitProcessCapsInterlock(qemuCaps);
+
+    return 0;
+}
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 8cd221062c..ff26885ffe 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -1197,3 +1197,9 @@ qemuDomainMachineSupportsFloppy(const char *machine,
 
 virObject *
 qemuDomainHostdevPrivateNew(void);
+
+int
+qemuDomainUpdateCustomCapabilities(const virDomainDef *def,
+                                   virQEMUCaps *qemuCaps,
+                                   virQEMUCaps **qemuCapsCopy)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) G_GNUC_WARN_UNUSED_RESULT;
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 7d9f754fc2..1540c74087 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -5823,43 +5823,6 @@ qemuProcessStartValidate(virQEMUDriver *driver,
 }
 
 
-static int
-qemuProcessStartUpdateCustomCaps(virDomainObj *vm)
-{
-    qemuDomainObjPrivate *priv = vm->privateData;
-    qemuDomainXmlNsDef *nsdef = vm->def->namespaceData;
-
-    if (nsdef) {
-        char **next;
-        int tmp;
-
-        for (next = nsdef->capsadd; next && *next; next++) {
-            if ((tmp = virQEMUCapsTypeFromString(*next)) < 0) {
-                virReportError(VIR_ERR_INTERNAL_ERROR,
-                               _("invalid qemu namespace capability '%1$s'"),
-                               *next);
-                return -1;
-            }
-
-            virQEMUCapsSet(priv->qemuCaps, tmp);
-        }
-
-        for (next = nsdef->capsdel; next && *next; next++) {
-            if ((tmp = virQEMUCapsTypeFromString(*next)) < 0) {
-                virReportError(VIR_ERR_INTERNAL_ERROR,
-                               _("invalid qemu namespace capability '%1$s'"),
-                               *next);
-                return -1;
-            }
-
-            virQEMUCapsClear(priv->qemuCaps, tmp);
-        }
-    }
-
-    return 0;
-}
-
-
 /**
  * qemuProcessPrepareQEMUCaps:
  * @vm: domain object
@@ -5883,12 +5846,9 @@ qemuProcessPrepareQEMUCaps(virDomainObj *vm,
         return -1;
 
     /* Update qemu capabilities according to lists passed in via namespace */
-    if (qemuProcessStartUpdateCustomCaps(vm) < 0)
+    if (qemuDomainUpdateCustomCapabilities(vm->def, priv->qemuCaps, NULL) < 0)
         return -1;
 
-    /* re-process capability lockouts since we might have removed capabilities */
-    virQEMUCapsInitProcessCapsInterlock(priv->qemuCaps);
-
     return 0;
 }
 
-- 
2.55.0