From c4583c8c394ee49ce7d5271f572abd3b000fa9e4 Mon Sep 17 00:00:00 2001 From: Paul Durrant Date: Thu, 1 Oct 2020 09:15:00 +0100 Subject: xen-bus: reduce scope of backend watch Currently a single watch on /local/domain/X/backend is registered by each QEMU process running in service domain X (where X is usually 0). The purpose of this watch is to ensure that QEMU is notified when the Xen toolstack creates a new device backend area. Such a backend area is specific to a single frontend area created for a specific guest domain and, since each QEMU process is also created to service a specfic guest domain, it is unnecessary and inefficient to notify all QEMU processes. Only the QEMU process associated with the same guest domain need receive the notification. This patch re-factors the watch registration code such that notifications are targetted appropriately. Reported-by: Jerome Leseinne Signed-off-by: Paul Durrant Reviewed-by: Anthony PERARD Message-Id: <20201001081500.1026-1-paul@xen.org> Signed-off-by: Anthony PERARD --- include/hw/xen/xen-backend.h | 1 + include/hw/xen/xen-bus.h | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/hw/xen/xen-backend.h b/include/hw/xen/xen-backend.h index 010d712..aac2fd4 100644 --- a/include/hw/xen/xen-backend.h +++ b/include/hw/xen/xen-backend.h @@ -31,6 +31,7 @@ void xen_backend_set_device(XenBackendInstance *backend, XenDevice *xen_backend_get_device(XenBackendInstance *backend); void xen_backend_register(const XenBackendInfo *info); +const char **xen_backend_get_types(unsigned int *nr); void xen_backend_device_create(XenBus *xenbus, const char *type, const char *name, QDict *opts, Error **errp); diff --git a/include/hw/xen/xen-bus.h b/include/hw/xen/xen-bus.h index 3df6961..6bdbf3f 100644 --- a/include/hw/xen/xen-bus.h +++ b/include/hw/xen/xen-bus.h @@ -66,7 +66,8 @@ struct XenBus { domid_t backend_id; struct xs_handle *xsh; XenWatchList *watch_list; - XenWatch *backend_watch; + unsigned int backend_types; + XenWatch **backend_watch; QLIST_HEAD(, XenDevice) inactive_devices; }; -- cgit v1.1