It is not safe to close an event channel from the QEMU main thread when that channel's poller is running in IOThread context. This patch adds a new xen_device_set_event_channel_context() function to explicitly assign the channel AioContext, and modifies xen_device_bind_event_channel() to initially assign the channel's poller to the QEMU main thread context. The code in xen-block's dataplane is then modified to assign the channel to IOThread context during xen_block_dataplane_start() and de-assign it during in xen_block_dataplane_stop(), such that the channel is always assigned back to main thread context before it is closed. aio_set_fd_handler() already deals with all the necessary synchronization when moving an fd between AioContext-s so no extra code is needed to manage this. Reported-by: Julien Grall <jgrall@amazon.com> Signed-off-by: Paul Durrant <pdurrant@amazon.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Message-Id: <20191216143451.19024-1-pdurrant@amazon.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
		
			
				
	
	
		
			146 lines
		
	
	
		
			4.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			146 lines
		
	
	
		
			4.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Copyright (c) 2018  Citrix Systems Inc.
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2 or later.
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 * See the COPYING file in the top-level directory.
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 */
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#ifndef HW_XEN_BUS_H
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#define HW_XEN_BUS_H
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#include "hw/xen/xen_common.h"
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#include "hw/sysbus.h"
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#include "qemu/notify.h"
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typedef void (*XenWatchHandler)(void *opaque);
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typedef struct XenWatchList XenWatchList;
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typedef struct XenWatch XenWatch;
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typedef struct XenEventChannel XenEventChannel;
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typedef struct XenDevice {
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    DeviceState qdev;
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    domid_t frontend_id;
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    char *name;
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    struct xs_handle *xsh;
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    XenWatchList *watch_list;
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    char *backend_path, *frontend_path;
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    enum xenbus_state backend_state, frontend_state;
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    Notifier exit;
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    XenWatch *backend_state_watch, *frontend_state_watch;
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    bool backend_online;
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    XenWatch *backend_online_watch;
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    xengnttab_handle *xgth;
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    bool feature_grant_copy;
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    bool inactive;
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    QLIST_HEAD(, XenEventChannel) event_channels;
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    QLIST_ENTRY(XenDevice) list;
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} XenDevice;
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typedef char *(*XenDeviceGetName)(XenDevice *xendev, Error **errp);
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typedef void (*XenDeviceRealize)(XenDevice *xendev, Error **errp);
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typedef void (*XenDeviceFrontendChanged)(XenDevice *xendev,
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                                         enum xenbus_state frontend_state,
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                                         Error **errp);
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typedef void (*XenDeviceUnrealize)(XenDevice *xendev, Error **errp);
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typedef struct XenDeviceClass {
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    /*< private >*/
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    DeviceClass parent_class;
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    /*< public >*/
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    const char *backend;
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    const char *device;
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    XenDeviceGetName get_name;
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    XenDeviceRealize realize;
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    XenDeviceFrontendChanged frontend_changed;
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    XenDeviceUnrealize unrealize;
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} XenDeviceClass;
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#define TYPE_XEN_DEVICE "xen-device"
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#define XEN_DEVICE(obj) \
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     OBJECT_CHECK(XenDevice, (obj), TYPE_XEN_DEVICE)
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#define XEN_DEVICE_CLASS(class) \
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     OBJECT_CLASS_CHECK(XenDeviceClass, (class), TYPE_XEN_DEVICE)
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#define XEN_DEVICE_GET_CLASS(obj) \
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     OBJECT_GET_CLASS(XenDeviceClass, (obj), TYPE_XEN_DEVICE)
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typedef struct XenBus {
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    BusState qbus;
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    domid_t backend_id;
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    struct xs_handle *xsh;
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    XenWatchList *watch_list;
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    XenWatch *backend_watch;
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    QLIST_HEAD(, XenDevice) inactive_devices;
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} XenBus;
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typedef struct XenBusClass {
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    /*< private >*/
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    BusClass parent_class;
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} XenBusClass;
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#define TYPE_XEN_BUS "xen-bus"
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#define XEN_BUS(obj) \
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    OBJECT_CHECK(XenBus, (obj), TYPE_XEN_BUS)
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#define XEN_BUS_CLASS(class) \
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    OBJECT_CLASS_CHECK(XenBusClass, (class), TYPE_XEN_BUS)
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#define XEN_BUS_GET_CLASS(obj) \
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    OBJECT_GET_CLASS(XenBusClass, (obj), TYPE_XEN_BUS)
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void xen_bus_init(void);
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void xen_device_backend_set_state(XenDevice *xendev,
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                                  enum xenbus_state state);
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enum xenbus_state xen_device_backend_get_state(XenDevice *xendev);
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void xen_device_backend_printf(XenDevice *xendev, const char *key,
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                               const char *fmt, ...)
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    GCC_FMT_ATTR(3, 4);
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void xen_device_frontend_printf(XenDevice *xendev, const char *key,
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                                const char *fmt, ...)
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    GCC_FMT_ATTR(3, 4);
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int xen_device_frontend_scanf(XenDevice *xendev, const char *key,
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                              const char *fmt, ...);
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void xen_device_set_max_grant_refs(XenDevice *xendev, unsigned int nr_refs,
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                                   Error **errp);
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void *xen_device_map_grant_refs(XenDevice *xendev, uint32_t *refs,
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                                unsigned int nr_refs, int prot,
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                                Error **errp);
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void xen_device_unmap_grant_refs(XenDevice *xendev, void *map,
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                                 unsigned int nr_refs, Error **errp);
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typedef struct XenDeviceGrantCopySegment {
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    union {
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        void *virt;
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        struct {
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            uint32_t ref;
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            off_t offset;
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        } foreign;
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    } source, dest;
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    size_t len;
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} XenDeviceGrantCopySegment;
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void xen_device_copy_grant_refs(XenDevice *xendev, bool to_domain,
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                                XenDeviceGrantCopySegment segs[],
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                                unsigned int nr_segs, Error **errp);
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typedef bool (*XenEventHandler)(void *opaque);
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XenEventChannel *xen_device_bind_event_channel(XenDevice *xendev,
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                                               unsigned int port,
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                                               XenEventHandler handler,
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                                               void *opaque, Error **errp);
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void xen_device_set_event_channel_context(XenDevice *xendev,
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                                          XenEventChannel *channel,
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                                          AioContext *ctx,
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                                          Error **errp);
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void xen_device_notify_event_channel(XenDevice *xendev,
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                                     XenEventChannel *channel,
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                                     Error **errp);
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void xen_device_unbind_event_channel(XenDevice *xendev,
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                                     XenEventChannel *channel,
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                                     Error **errp);
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#endif /* HW_XEN_BUS_H */
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