qemu: remove default audio backend for migratable XML

When seeing a guest with a sound device, and no audio backend, we
automatically add an audio backend XML element based on the historical
QEMU driver behaviour. Unfortunately when we live migrate back to an
old libvirt, it may not understand the audio driver type we configured.
We thus need to strip the default audio backend when migrating.

Fixes https://gitlab.com/libvirt/libvirt/-/issues/179
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 43e6398ae5362564ebf61027548886c4a8d8977b..cc7533a707172629cd75a1595efc221579fa164b 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -226,6 +226,7 @@ virDiskNameParse;
 virDiskNameToBusDeviceIndex;
 virDiskNameToIndex;
 virDomainActualNetDefFree;
+virDomainAudioDefFree;
 virDomainAudioFormatTypeFromString;
 virDomainAudioFormatTypeToString;
 virDomainAudioIOCommonIsSet;

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 8488f58e09e6c6a0f53c26e7be752d0dc1b2b3c0..3af678a2831f500545cdbb4672e6b45ebdd587d6 100644 (file)
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -3587,18 +3587,19 @@ qemuDomainDefAddImplicitInputDevice(virDomainDef *def)
 }
 
 static int
-qemuDomainDefAddDefaultAudioBackend(virQEMUDriver *driver,
-                                    virDomainDef *def)
+qemuDomainDefSuggestDefaultAudioBackend(virQEMUDriver *driver,
+                                        virDomainDef *def,
+                                        bool *addAudio,
+                                        int *audioBackend,
+                                        int *audioSDLDriver)
 {
     size_t i;
-    bool addAudio = false;
     bool audioPassthrough = false;
-    int audioBackend = VIR_DOMAIN_AUDIO_TYPE_NONE;
     g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
 
-    if (def->naudios > 0) {
-        return 0;
-    }
+    *addAudio = false;
+    *audioBackend = VIR_DOMAIN_AUDIO_TYPE_NONE;
+    *audioSDLDriver = VIR_DOMAIN_AUDIO_SDL_DRIVER_DEFAULT;
 
     for (i = 0; i < def->ngraphics; i++) {
         virDomainGraphicsDef *graph = def->graphics[i];
@@ -3609,18 +3610,18 @@ qemuDomainDefAddDefaultAudioBackend(virQEMUDriver *driver,
                 audioPassthrough = true;
             } else {
                 audioPassthrough = false;
-                audioBackend = VIR_DOMAIN_AUDIO_TYPE_NONE;
+                *audioBackend = VIR_DOMAIN_AUDIO_TYPE_NONE;
             }
-            addAudio = true;
+            *addAudio = true;
             break;
         case VIR_DOMAIN_GRAPHICS_TYPE_SPICE:
             audioPassthrough = false;
-            audioBackend = VIR_DOMAIN_AUDIO_TYPE_SPICE;
-            addAudio = true;
+            *audioBackend = VIR_DOMAIN_AUDIO_TYPE_SPICE;
+            *addAudio = true;
             break;
         case VIR_DOMAIN_GRAPHICS_TYPE_SDL:
             audioPassthrough = true;
-            addAudio = true;
+            *addAudio = true;
             break;
 
         case VIR_DOMAIN_GRAPHICS_TYPE_RDP:
@@ -3639,24 +3640,24 @@ qemuDomainDefAddDefaultAudioBackend(virQEMUDriver *driver,
             audioPassthrough = true;
         } else {
             audioPassthrough = false;
-            audioBackend = VIR_DOMAIN_AUDIO_TYPE_NONE;
+            *audioBackend = VIR_DOMAIN_AUDIO_TYPE_NONE;
         }
-        addAudio = true;
+        *addAudio = true;
     }
 
-    if (addAudio && audioPassthrough) {
+    if (*addAudio && audioPassthrough) {
         const char *audioenv = g_getenv("QEMU_AUDIO_DRV");
         if (audioenv == NULL) {
-            addAudio = false;
+            *addAudio = false;
         } else {
             /*
              * QEMU audio driver names are mostly the same as
              * libvirt XML audio backend names
              */
             if (STREQ(audioenv, "pa")) {
-                audioBackend = VIR_DOMAIN_AUDIO_TYPE_PULSEAUDIO;
+                *audioBackend = VIR_DOMAIN_AUDIO_TYPE_PULSEAUDIO;
             } else {
-                if ((audioBackend = virDomainAudioTypeTypeFromString(audioenv)) < 0) {
+                if (((*audioBackend) = virDomainAudioTypeTypeFromString(audioenv)) < 0) {
                     virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                                    _("unknown QEMU_AUDIO_DRV setting %s"), audioenv);
                     return -1;
@@ -3664,6 +3665,79 @@ qemuDomainDefAddDefaultAudioBackend(virQEMUDriver *driver,
             }
         }
     }
+
+    if (*addAudio && *audioBackend == VIR_DOMAIN_AUDIO_TYPE_SDL) {
+        const char *sdldriver = g_getenv("SDL_AUDIODRIVER");
+        if (sdldriver != NULL &&
+            (((*audioSDLDriver) =
+              virDomainAudioSDLDriverTypeFromString(sdldriver)) <= 0)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("unknown SDL_AUDIODRIVER setting %s"), sdldriver);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+static int
+qemuDomainDefClearDefaultAudioBackend(virQEMUDriver *driver,
+                                      virDomainDef *def)
+{
+    bool addAudio;
+    int audioBackend;
+    int audioSDLDriver;
+    virDomainAudioDef *audio;
+
+    if (def->naudios != 1) {
+        return 0;
+    }
+
+    if (qemuDomainDefSuggestDefaultAudioBackend(driver,
+                                                def,
+                                                &addAudio,
+                                                &audioBackend,
+                                                &audioSDLDriver) < 0)
+        return -1;
+
+    if (!addAudio)
+        return 0;
+
+    audio = def->audios[0];
+    if (audio->type != audioBackend)
+        return 0;
+
+    if (audio->type == VIR_DOMAIN_AUDIO_TYPE_SDL &&
+        audio->backend.sdl.driver != audioSDLDriver)
+        return 0;
+
+    virDomainAudioDefFree(audio);
+    g_free(def->audios);
+    def->naudios = 0;
+    def->audios = NULL;
+
+    return 0;
+}
+
+static int
+qemuDomainDefAddDefaultAudioBackend(virQEMUDriver *driver,
+                                    virDomainDef *def)
+{
+    bool addAudio;
+    int audioBackend;
+    int audioSDLDriver;
+
+    if (def->naudios > 0) {
+        return 0;
+    }
+
+    if (qemuDomainDefSuggestDefaultAudioBackend(driver,
+                                                def,
+                                                &addAudio,
+                                                &audioBackend,
+                                                &audioSDLDriver) < 0)
+        return -1;
+
     if (addAudio) {
         virDomainAudioDef *audio = g_new0(virDomainAudioDef, 1);
 
@@ -3674,16 +3748,8 @@ qemuDomainDefAddDefaultAudioBackend(virQEMUDriver *driver,
         def->audios = g_new0(virDomainAudioDef *, def->naudios);
         def->audios[0] = audio;
 
-        if (audioBackend == VIR_DOMAIN_AUDIO_TYPE_SDL) {
-            const char *sdldriver = g_getenv("SDL_AUDIODRIVER");
-            if (sdldriver != NULL &&
-                ((audio->backend.sdl.driver =
-                  virDomainAudioSDLDriverTypeFromString(sdldriver)) <= 0)) {
-                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
-                               _("unknown SDL_AUDIODRIVER setting %s"), sdldriver);
-                return -1;
-            }
-        }
+        if (audioBackend == VIR_DOMAIN_AUDIO_TYPE_SDL)
+            audio->backend.sdl.driver = audioSDLDriver;
     }
 
     return 0;
@@ -6298,6 +6364,12 @@ qemuDomainDefFormatBufInternal(virQEMUDriver *driver,
 
         if (def->cpu && qemuDomainMakeCPUMigratable(def->cpu) < 0)
             return -1;
+
+        /* Old libvirt doesn't understand <audio> elements so
+         * remove any we added by default
+         */
+        if (qemuDomainDefClearDefaultAudioBackend(driver, def) < 0)
+            return -1;
     }
 
  format:

diff --git a/tests/qemumigrationcookiexmldata/full-xml2xml-out.xml b/tests/qemumigrationcookiexmldata/full-xml2xml-out.xml
index 013cfb1eb2e0b44b957643b418ab4a4885348626..a07dd1f147dae9d057f6304914732b8bb0032224 100644 (file)
--- a/tests/qemumigrationcookiexmldata/full-xml2xml-out.xml
+++ b/tests/qemumigrationcookiexmldata/full-xml2xml-out.xml
@@ -142,7 +142,6 @@
       <sound model='ich6'>
         <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
       </sound>
-      <audio id='1' type='spice'/>
       <video>
         <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/>
         <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>