xemu/include/hw/xen/xen-bus.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

140 lines
4.6 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_BUS_H
#define HW_XEN_BUS_H
#include "hw/xen/xen_common.h"
#include "hw/sysbus.h"
#include "qemu/notify.h"
#include "qom/object.h"
typedef void (*XenWatchHandler)(void *opaque);
typedef struct XenWatchList XenWatchList;
typedef struct XenWatch XenWatch;
typedef struct XenEventChannel XenEventChannel;
struct XenDevice {
DeviceState qdev;
domid_t frontend_id;
char *name;
struct xs_handle *xsh;
XenWatchList *watch_list;
char *backend_path, *frontend_path;
enum xenbus_state backend_state, frontend_state;
Notifier exit;
XenWatch *backend_state_watch, *frontend_state_watch;
bool backend_online;
XenWatch *backend_online_watch;
xengnttab_handle *xgth;
bool feature_grant_copy;
bool inactive;
QLIST_HEAD(, XenEventChannel) event_channels;
QLIST_ENTRY(XenDevice) list;
};
typedef struct XenDevice XenDevice;
typedef char *(*XenDeviceGetName)(XenDevice *xendev, Error **errp);
typedef void (*XenDeviceRealize)(XenDevice *xendev, Error **errp);
typedef void (*XenDeviceFrontendChanged)(XenDevice *xendev,
enum xenbus_state frontend_state,
Error **errp);
typedef void (*XenDeviceUnrealize)(XenDevice *xendev);
struct XenDeviceClass {
/*< private >*/
DeviceClass parent_class;
/*< public >*/
const char *backend;
const char *device;
XenDeviceGetName get_name;
XenDeviceRealize realize;
XenDeviceFrontendChanged frontend_changed;
XenDeviceUnrealize unrealize;
};
#define TYPE_XEN_DEVICE "xen-device"
OBJECT_DECLARE_TYPE(XenDevice, XenDeviceClass, XEN_DEVICE)
struct XenBus {
BusState qbus;
domid_t backend_id;
struct xs_handle *xsh;
XenWatchList *watch_list;
unsigned int backend_types;
XenWatch **backend_watch;
QLIST_HEAD(, XenDevice) inactive_devices;
};
struct XenBusClass {
/*< private >*/
BusClass parent_class;
};
#define TYPE_XEN_BUS "xen-bus"
OBJECT_DECLARE_TYPE(XenBus, XenBusClass,
XEN_BUS)
void xen_bus_init(void);
void xen_device_backend_set_state(XenDevice *xendev,
enum xenbus_state state);
enum xenbus_state xen_device_backend_get_state(XenDevice *xendev);
void xen_device_backend_printf(XenDevice *xendev, const char *key,
const char *fmt, ...)
GCC_FMT_ATTR(3, 4);
void xen_device_frontend_printf(XenDevice *xendev, const char *key,
const char *fmt, ...)
GCC_FMT_ATTR(3, 4);
int xen_device_frontend_scanf(XenDevice *xendev, const char *key,
const char *fmt, ...);
void xen_device_set_max_grant_refs(XenDevice *xendev, unsigned int nr_refs,
Error **errp);
void *xen_device_map_grant_refs(XenDevice *xendev, uint32_t *refs,
unsigned int nr_refs, int prot,
Error **errp);
void xen_device_unmap_grant_refs(XenDevice *xendev, void *map,
unsigned int nr_refs, Error **errp);
typedef struct XenDeviceGrantCopySegment {
union {
void *virt;
struct {
uint32_t ref;
off_t offset;
} foreign;
} source, dest;
size_t len;
} XenDeviceGrantCopySegment;
void xen_device_copy_grant_refs(XenDevice *xendev, bool to_domain,
XenDeviceGrantCopySegment segs[],
unsigned int nr_segs, Error **errp);
typedef bool (*XenEventHandler)(void *opaque);
XenEventChannel *xen_device_bind_event_channel(XenDevice *xendev,
unsigned int port,
XenEventHandler handler,
void *opaque, Error **errp);
void xen_device_set_event_channel_context(XenDevice *xendev,
XenEventChannel *channel,
AioContext *ctx,
Error **errp);
void xen_device_notify_event_channel(XenDevice *xendev,
XenEventChannel *channel,
Error **errp);
void xen_device_unbind_event_channel(XenDevice *xendev,
XenEventChannel *channel,
Error **errp);
#endif /* HW_XEN_BUS_H */