qemu: Make memory path generation embed driver aware

So far, libvirt generates the following path for memory:

  $memoryBackingDir/$id-$shortName/ram-nodeN

where $memoryBackingDir is the path where QEMU mmaps() memory for
the guest (e.g. /var/lib/libvirt/qemu/ram), $id is domain ID
and $shortName is shortened version of domain name. So for
instance, the generated path may look something like this:

  /var/lib/libvirt/qemu/ram/1-QEMUGuest/ram-node0

While in case of embed driver the following path would be
generated by default:

  $root/lib/qemu/ram/1-QEMUGuest/ram-node0

which is not clashing with other embed drivers, we allow users to
override the default and have all embed drivers use the same
prefix. This can create clashing paths. Fortunately, we can reuse
the approach for machined name generation
(v6.1.0-178-gc9bd08ee35) and include part of hash of the root in
the generated path.

Note, the important change is in qemuGetMemoryBackingBasePath().
The rest is needed to pass driver around.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 62bacf27856560cc2ed506f55fd4a0087c995832..988d38e434d818e66aa95d7954d78f7e2fb7506b 100644 (file)
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3479,7 +3479,7 @@ qemuBuildMemoryBackendProps(virJSONValuePtr *backendProps,
         } else {
             /* We can have both pagesize and mem source. If that's the case,
              * prefer hugepages as those are more specific. */
-            if (qemuGetMemoryBackingPath(def, cfg, mem->info.alias, &memPath) < 0)
+            if (qemuGetMemoryBackingPath(priv->driver, def, mem->info.alias, &memPath) < 0)
                 return -1;
         }
 
@@ -7240,11 +7240,11 @@ qemuBuildSmpCommandLine(virCommandPtr cmd,
 
 
 static int
-qemuBuildMemPathStr(virQEMUDriverConfigPtr cfg,
-                    const virDomainDef *def,
+qemuBuildMemPathStr(const virDomainDef *def,
                     virCommandPtr cmd,
                     qemuDomainObjPrivatePtr priv)
 {
+    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(priv->driver);
     const long system_page_size = virGetSystemPageSizeKB();
     g_autofree char *mem_path = NULL;
 
@@ -7261,7 +7261,7 @@ qemuBuildMemPathStr(virQEMUDriverConfigPtr cfg,
         if (qemuGetDomainHupageMemPath(priv->driver, def, pagesize, &mem_path) < 0)
             return -1;
     } else if (def->mem.source == VIR_DOMAIN_MEMORY_SOURCE_FILE) {
-        if (qemuGetMemoryBackingPath(def, cfg, "ram", &mem_path) < 0)
+        if (qemuGetMemoryBackingPath(priv->driver, def, "ram", &mem_path) < 0)
             return -1;
     } else {
         return 0;
@@ -7280,7 +7280,6 @@ qemuBuildMemPathStr(virQEMUDriverConfigPtr cfg,
 
 static int
 qemuBuildMemCommandLine(virCommandPtr cmd,
-                        virQEMUDriverConfigPtr cfg,
                         const virDomainDef *def,
                         virQEMUCapsPtr qemuCaps,
                         qemuDomainObjPrivatePtr priv)
@@ -7312,7 +7311,7 @@ qemuBuildMemCommandLine(virCommandPtr cmd,
      * the hugepages and no numa node is specified.
      */
     if (!virDomainNumaGetNodeCount(def->numa) &&
-        qemuBuildMemPathStr(cfg, def, cmd, priv) < 0)
+        qemuBuildMemPathStr(def, cmd, priv) < 0)
         return -1;
 
     if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_OVERCOMMIT)) {
@@ -7393,7 +7392,7 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
     }
 
     if (!needBackend &&
-        qemuBuildMemPathStr(cfg, def, cmd, priv) < 0)
+        qemuBuildMemPathStr(def, cmd, priv) < 0)
         goto cleanup;
 
     for (i = 0; i < ncells; i++) {
@@ -9886,7 +9885,7 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
     if (!migrateURI && !snapshot && qemuDomainAlignMemorySizes(def) < 0)
         return NULL;
 
-    if (qemuBuildMemCommandLine(cmd, cfg, def, qemuCaps, priv) < 0)
+    if (qemuBuildMemCommandLine(cmd, def, qemuCaps, priv) < 0)
         return NULL;
 
     if (qemuBuildSmpCommandLine(cmd, def, qemuCaps) < 0)

diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index 713542f8cd0d2833f6018197c28615f05f07b909..c59824006c21929af68d4c32e28fc5947f3154e7 100644 (file)
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -1965,16 +1965,23 @@ qemuGetDomainHupageMemPath(virQEMUDriverPtr driver,
 
 
 int
-qemuGetMemoryBackingDomainPath(const virDomainDef *def,
-                               virQEMUDriverConfigPtr cfg,
+qemuGetMemoryBackingDomainPath(virQEMUDriverPtr driver,
+                               const virDomainDef *def,
                                char **path)
 {
+    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
+    const char *root = driver->embeddedRoot;
     g_autofree char *shortName = NULL;
 
     if (!(shortName = virDomainDefGetShortName(def)))
         return -1;
 
-    *path = g_strdup_printf("%s/%s", cfg->memoryBackingDir, shortName);
+    if (root && !STRPREFIX(cfg->memoryBackingDir, root)) {
+        g_autofree char * hash = virDomainDriverGenerateRootHash("qemu", root);
+        *path = g_strdup_printf("%s/%s-%s", cfg->memoryBackingDir, hash, shortName);
+    } else {
+        *path = g_strdup_printf("%s/%s", cfg->memoryBackingDir, shortName);
+    }
 
     return 0;
 }
@@ -1982,8 +1989,8 @@ qemuGetMemoryBackingDomainPath(const virDomainDef *def,
 
 /**
  * qemuGetMemoryBackingPath:
+ * @driver: the qemu driver
  * @def: domain definition
- * @cfg: the driver config
  * @alias: memory object alias
  * @memPath: constructed path
  *
@@ -1993,8 +2000,8 @@ qemuGetMemoryBackingDomainPath(const virDomainDef *def,
  *          -1 otherwise (with error reported).
  */
 int
-qemuGetMemoryBackingPath(const virDomainDef *def,
-                         virQEMUDriverConfigPtr cfg,
+qemuGetMemoryBackingPath(virQEMUDriverPtr driver,
+                         const virDomainDef *def,
                          const char *alias,
                          char **memPath)
 {
@@ -2007,7 +2014,7 @@ qemuGetMemoryBackingPath(const virDomainDef *def,
         return -1;
     }
 
-    if (qemuGetMemoryBackingDomainPath(def, cfg, &domainPath) < 0)
+    if (qemuGetMemoryBackingDomainPath(driver, def, &domainPath) < 0)
         return -1;
 
     *memPath = g_strdup_printf("%s/%s", domainPath, alias);

diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
index b85a9497b7dce8a28aebd0dc0bb6305b82c53b06..b9ef4551a328699af098cb5765623f5173224901 100644 (file)
--- a/src/qemu/qemu_conf.h
+++ b/src/qemu/qemu_conf.h
@@ -397,10 +397,10 @@ int qemuGetDomainHupageMemPath(virQEMUDriverPtr driver,
                                unsigned long long pagesize,
                                char **memPath);
 
-int qemuGetMemoryBackingDomainPath(const virDomainDef *def,
-                                   virQEMUDriverConfigPtr cfg,
+int qemuGetMemoryBackingDomainPath(virQEMUDriverPtr driver,
+                                   const virDomainDef *def,
                                    char **path);
-int qemuGetMemoryBackingPath(const virDomainDef *def,
-                             virQEMUDriverConfigPtr cfg,
+int qemuGetMemoryBackingPath(virQEMUDriverPtr driver,
+                             const virDomainDef *def,
                              const char *alias,
                              char **memPath);

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index f9c400059f674703ac21964f6e8d4ad788fda731..8ea470f75f2c099106cfdad4aabb8b0a43833553 100644 (file)
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -3894,7 +3894,7 @@ qemuProcessBuildDestroyMemoryPaths(virQEMUDriverPtr driver,
 
     if (!build || shouldBuildMB) {
         g_autofree char *path = NULL;
-        if (qemuGetMemoryBackingDomainPath(vm->def, cfg, &path) < 0)
+        if (qemuGetMemoryBackingDomainPath(driver, vm->def, &path) < 0)
             return -1;
 
         if (qemuProcessBuildDestroyMemoryPathsImpl(driver, vm,
@@ -3911,10 +3911,9 @@ qemuProcessDestroyMemoryBackingPath(virQEMUDriverPtr driver,
                                     virDomainObjPtr vm,
                                     virDomainMemoryDefPtr mem)
 {
-    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
     g_autofree char *path = NULL;
 
-    if (qemuGetMemoryBackingPath(vm->def, cfg, mem->info.alias, &path) < 0)
+    if (qemuGetMemoryBackingPath(driver, vm->def, mem->info.alias, &path) < 0)
         return -1;
 
     if (unlink(path) < 0 &&