Add vm.overrides property in pipewire and pulse-server

Apply vm.override properties when running in a VM. Increase the
default quantum to 1024 when running in a VM to cause less
dropouts.

src/daemon/pipewire-pulse.conf.in

@@ -43,6 +43,10 @@ context.modules = [
 	    #pulse.min.quantum = 256/48000          # 5ms
 	    #pulse.default.format = F32
 	    #pulse.default.position = [ FL FR ]
+            # These overrides are only applied when running in a vm.
+            vm.overrides = {
+	        pulse.min.quantum = 1024/48000         # 22ms
+            }
         }
     }
 ]

src/daemon/pipewire.conf.in

@@ -25,6 +25,11 @@ context.properties = {
     #default.video.height      = 480
     #default.video.rate.num    = 25
     #default.video.rate.denom  = 1
+    #
+    # These overrides are only applied when running in a vm.
+    vm.overrides = {
+        default.clock.min-quantum     = 1024
+    }
 }
 
 context.spa-libs = {

src/modules/module-protocol-pulse/pulse-server.c

@@ -60,6 +60,7 @@
 
 #define spa_debug pw_log_debug
 
+#include <spa/support/cpu.h>
 #include <spa/utils/result.h>
 #include <spa/debug/dict.h>
 #include <spa/debug/mem.h>
@@ -6225,27 +6226,29 @@ struct pw_protocol_pulse *pw_protocol_pulse_new(struct pw_context *context,
 	const char *str;
 	struct spa_json it[2];
 	char value[512];
+	const struct spa_support *support;
+	struct spa_cpu *cpu;
+	uint32_t n_support;
 	int res;
 
 	impl = calloc(1, sizeof(struct impl) + user_data_size);
 	if (impl == NULL)
 		goto error_exit;
 
+
 	if (props == NULL)
 		props = pw_properties_new(NULL, NULL);
 	if (props == NULL)
 		goto error_free;
 
-	str = pw_properties_get(props, "server.address");
+	support = pw_context_get_support(context, &n_support);
-	if (str == NULL) {
+	cpu = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_CPU);
-		pw_properties_setf(props, "server.address",
+
-				"[ \"%s-%s\" ]",
+	if ((str = pw_properties_get(props, "vm.overrides")) != NULL) {
-				PW_PROTOCOL_PULSE_DEFAULT_SERVER,
+		if (cpu != NULL && spa_cpu_get_vm_type(cpu) != SPA_CPU_VM_NONE)
-				get_server_name(context));
+			pw_properties_update_string(props, str, strlen(str));
-		str = pw_properties_get(props, "server.address");
+		pw_properties_set(props, "vm.overrides", NULL);
 	}
-	if (str == NULL)
-		goto error_free;
 
 	load_defaults(&impl->defs, props);
 
@@ -6270,6 +6273,17 @@ struct pw_protocol_pulse *pw_protocol_pulse_new(struct pw_context *context,
 	pw_context_add_listener(context, &impl->context_listener,
 			&context_events, impl);
 
+	str = pw_properties_get(props, "server.address");
+	if (str == NULL) {
+		pw_properties_setf(props, "server.address",
+				"[ \"%s-%s\" ]",
+				PW_PROTOCOL_PULSE_DEFAULT_SERVER,
+				get_server_name(context));
+		str = pw_properties_get(props, "server.address");
+	}
+	if (str == NULL)
+		goto error_free;
+
 	spa_json_init(&it[0], str, strlen(str));
 	if (spa_json_enter_array(&it[0], &it[1]) > 0) {
 		while (spa_json_get_string(&it[1], value, sizeof(value)-1) > 0) {

src/pipewire/context.c

@@ -246,11 +246,23 @@ struct pw_context *pw_context_new(struct pw_loop *main_loop,
 	}
 	this->conf = conf;
 
+	n_support = pw_get_support(this->support, SPA_N_ELEMENTS(this->support) - 6);
+	cpu = spa_support_find(this->support, n_support, SPA_TYPE_INTERFACE_CPU);
+
 	if ((str = pw_properties_get(conf, "context.properties")) != NULL) {
 		pw_properties_update_string(properties, str, strlen(str));
 		pw_log_info(NAME" %p: parsed context.properties section", this);
 	}
 
+	if ((str = pw_properties_get(properties, "vm.overrides")) != NULL) {
+		if (cpu != NULL && spa_cpu_get_vm_type(cpu) != SPA_CPU_VM_NONE)
+			pw_properties_update_string(properties, str, strlen(str));
+		pw_properties_set(properties, "vm.overrides", NULL);
+	}
+	if (pw_properties_get(properties, PW_KEY_CPU_MAX_ALIGN) == NULL && cpu != NULL)
+		pw_properties_setf(properties, PW_KEY_CPU_MAX_ALIGN,
+				"%u", spa_cpu_get_max_align(cpu));
+
 	if (getenv("PIPEWIRE_DEBUG") == NULL &&
 	    (str = pw_properties_get(properties, "log.level")) != NULL)
 		pw_log_set_level(atoi(str));
@@ -287,16 +299,12 @@ struct pw_context *pw_context_new(struct pw_loop *main_loop,
 	this->data_system = this->data_loop->system;
 	this->main_loop = main_loop;
 
-	n_support = pw_get_support(this->support, SPA_N_ELEMENTS(this->support) - 6);
 	this->support[n_support++] = SPA_SUPPORT_INIT(SPA_TYPE_INTERFACE_System, this->main_loop->system);
 	this->support[n_support++] = SPA_SUPPORT_INIT(SPA_TYPE_INTERFACE_Loop, this->main_loop->loop);
 	this->support[n_support++] = SPA_SUPPORT_INIT(SPA_TYPE_INTERFACE_LoopUtils, this->main_loop->utils);
 	this->support[n_support++] = SPA_SUPPORT_INIT(SPA_TYPE_INTERFACE_DataSystem, this->data_system);
 	this->support[n_support++] = SPA_SUPPORT_INIT(SPA_TYPE_INTERFACE_DataLoop, this->data_loop->loop);
 
-	if ((cpu = spa_support_find(this->support, n_support, SPA_TYPE_INTERFACE_CPU)) != NULL)
-		pw_properties_setf(properties, PW_KEY_CPU_MAX_ALIGN, "%u", spa_cpu_get_max_align(cpu));
-
 	if ((str = pw_properties_get(properties, "support.dbus")) == NULL ||
 	    pw_properties_parse_bool(str)) {
 		lib = pw_properties_get(properties, PW_KEY_LIBRARY_NAME_DBUS);