520d8b40e8
The vhost-user-blk export runs requests asynchronously in their own coroutine. When the vhost connection goes away and we want to stop the vhost-user server, we need to wait for these coroutines to stop before we can unmap the shared memory. Otherwise, they would still access the unmapped memory and crash. This introduces a refcount to VuServer which is increased when spawning a new request coroutine and decreased before the coroutine exits. The memory is only unmapped when the refcount reaches zero. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20220125151435.48792-1-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
71 lines
2.1 KiB
C
71 lines
2.1 KiB
C
/*
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* Sharing QEMU devices via vhost-user protocol
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*
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* Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
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* Copyright (c) 2020 Red Hat, Inc.
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or
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* later. See the COPYING file in the top-level directory.
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*/
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#ifndef VHOST_USER_SERVER_H
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#define VHOST_USER_SERVER_H
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#include "subprojects/libvhost-user/libvhost-user.h" /* only for the type definitions */
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#include "io/channel-socket.h"
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#include "io/channel-file.h"
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#include "io/net-listener.h"
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#include "qemu/error-report.h"
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#include "qapi/error.h"
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#include "standard-headers/linux/virtio_blk.h"
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/* A kick fd that we monitor on behalf of libvhost-user */
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typedef struct VuFdWatch {
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VuDev *vu_dev;
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int fd; /*kick fd*/
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void *pvt;
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vu_watch_cb cb;
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QTAILQ_ENTRY(VuFdWatch) next;
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} VuFdWatch;
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/**
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* VuServer:
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* A vhost-user server instance with user-defined VuDevIface callbacks.
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* Vhost-user device backends can be implemented using VuServer. VuDevIface
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* callbacks and virtqueue kicks run in the given AioContext.
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*/
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typedef struct {
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QIONetListener *listener;
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QEMUBH *restart_listener_bh;
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AioContext *ctx;
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int max_queues;
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const VuDevIface *vu_iface;
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/* Protected by ctx lock */
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unsigned int refcount;
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bool wait_idle;
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VuDev vu_dev;
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QIOChannel *ioc; /* The I/O channel with the client */
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QIOChannelSocket *sioc; /* The underlying data channel with the client */
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QTAILQ_HEAD(, VuFdWatch) vu_fd_watches;
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Coroutine *co_trip; /* coroutine for processing VhostUserMsg */
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} VuServer;
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bool vhost_user_server_start(VuServer *server,
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SocketAddress *unix_socket,
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AioContext *ctx,
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uint16_t max_queues,
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const VuDevIface *vu_iface,
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Error **errp);
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void vhost_user_server_stop(VuServer *server);
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void vhost_user_server_ref(VuServer *server);
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void vhost_user_server_unref(VuServer *server);
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void vhost_user_server_attach_aio_context(VuServer *server, AioContext *ctx);
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void vhost_user_server_detach_aio_context(VuServer *server);
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#endif /* VHOST_USER_SERVER_H */
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