From eb6ae7a6829385ca41227e878f5ca3d1faf31d52 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Mon, 16 Oct 2023 10:28:17 +0100 Subject: hw/xen: do not repeatedly try to create a failing backend device If xen_backend_device_create() fails to instantiate a device, the XenBus code will just keep trying over and over again each time the bus is re-enumerated, as long as the backend appears online and in XenbusStateInitialising. The only thing which prevents the XenBus code from recreating duplicates of devices which already exist, is the fact that xen_device_realize() sets the backend state to XenbusStateInitWait. If the attempt to create the device doesn't get *that* far, that's when it will keep getting retried. My first thought was to handle errors by setting the backend state to XenbusStateClosed, but that doesn't work for XenConsole which wants to *ignore* any device of type != "ioemu" completely. So, make xen_backend_device_create() *keep* the XenBackendInstance for a failed device, and provide a new xen_backend_exists() function to allow xen_bus_type_enumerate() to check whether one already exists before creating a new one. Signed-off-by: David Woodhouse Reviewed-by: Paul Durrant --- hw/xen/xen-backend.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) (limited to 'hw/xen/xen-backend.c') diff --git a/hw/xen/xen-backend.c b/hw/xen/xen-backend.c index 5b0fb76eae..b9bf70a9f5 100644 --- a/hw/xen/xen-backend.c +++ b/hw/xen/xen-backend.c @@ -101,6 +101,24 @@ static XenBackendInstance *xen_backend_list_find(XenDevice *xendev) return NULL; } +bool xen_backend_exists(const char *type, const char *name) +{ + const XenBackendImpl *impl = xen_backend_table_lookup(type); + XenBackendInstance *backend; + + if (!impl) { + return false; + } + + QLIST_FOREACH(backend, &backend_list, entry) { + if (backend->impl == impl && !strcmp(backend->name, name)) { + return true; + } + } + + return false; +} + static void xen_backend_list_remove(XenBackendInstance *backend) { QLIST_REMOVE(backend, entry); @@ -122,11 +140,6 @@ void xen_backend_device_create(XenBus *xenbus, const char *type, backend->name = g_strdup(name); impl->create(backend, opts, errp); - if (*errp) { - g_free(backend->name); - g_free(backend); - return; - } backend->impl = impl; xen_backend_list_add(backend); @@ -165,7 +178,9 @@ bool xen_backend_try_device_destroy(XenDevice *xendev, Error **errp) } impl = backend->impl; - impl->destroy(backend, errp); + if (backend->xendev) { + impl->destroy(backend, errp); + } xen_backend_list_remove(backend); g_free(backend->name); -- cgit v1.2.3