xemu/include/hw/xen/xen-backend.h
Paul Durrant c4583c8c39 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 <jerome.leseinne@gmail.com>
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Message-Id: <20201001081500.1026-1-paul@xen.org>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2020-10-19 16:32:41 +01:00

41 lines
1.3 KiB
C

/*
* Copyright (c) 2018 Citrix Systems Inc.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef HW_XEN_BACKEND_H
#define HW_XEN_BACKEND_H
#include "hw/xen/xen-bus.h"
typedef struct XenBackendInstance XenBackendInstance;
typedef void (*XenBackendDeviceCreate)(XenBackendInstance *backend,
QDict *opts, Error **errp);
typedef void (*XenBackendDeviceDestroy)(XenBackendInstance *backend,
Error **errp);
typedef struct XenBackendInfo {
const char *type;
XenBackendDeviceCreate create;
XenBackendDeviceDestroy destroy;
} XenBackendInfo;
XenBus *xen_backend_get_bus(XenBackendInstance *backend);
const char *xen_backend_get_name(XenBackendInstance *backend);
void xen_backend_set_device(XenBackendInstance *backend,
XenDevice *xendevice);
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);
bool xen_backend_try_device_destroy(XenDevice *xendev, Error **errp);
#endif /* HW_XEN_BACKEND_H */