/* $NetBSD: xbdback_xenbus.c,v 1.63 2016/12/26 08:16:28 skrll Exp $ */ /* * Copyright (c) 2006 Manuel Bouyer. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ #include __KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.63 2016/12/26 08:16:28 skrll Exp $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* #define XENDEBUG_VBD */ #ifdef XENDEBUG_VBD #define XENPRINTF(x) printf x #else #define XENPRINTF(x) #endif #define BLKIF_RING_SIZE __RING_SIZE((blkif_sring_t *)0, PAGE_SIZE) /* * Backend block device driver for Xen */ /* Max number of pages per request. The request may not be page aligned */ #define BLKIF_MAX_PAGES_PER_REQUEST (BLKIF_MAX_SEGMENTS_PER_REQUEST + 1) /* Values are expressed in 512-byte sectors */ #define VBD_BSIZE 512 #define VBD_MAXSECT ((PAGE_SIZE / VBD_BSIZE) - 1) struct xbdback_request; struct xbdback_io; struct xbdback_fragment; struct xbdback_instance; /* * status of a xbdback instance: * WAITING: xbdback instance is connected, waiting for requests * RUN: xbdi thread must be woken up, I/Os have to be processed * DISCONNECTING: the instance is closing, no more I/Os can be scheduled * DISCONNECTED: no I/Os, no ring, the thread should terminate. */ typedef enum {WAITING, RUN, DISCONNECTING, DISCONNECTED} xbdback_state_t; /* * Each xbdback instance is managed by a single thread that handles all * the I/O processing. As there are a variety of conditions that can block, * everything will be done in a sort of continuation-passing style. * * When the execution has to block to delay processing, for example to * allow system to recover because of memory shortage (via shared memory * callback), the return value of a continuation can be set to NULL. In that * case, the thread will go back to sleeping and wait for the proper * condition before it starts processing requests again from where it left. * Continuation state is "stored" in the xbdback instance (xbdi_cont and * xbdi_cont_aux), and should only be manipulated by the instance thread. * * As xbdback(4) has to handle different sort of asynchronous events (Xen * event channels, biointr() soft interrupts, xenbus commands), the xbdi_lock * mutex is used to protect specific elements of the xbdback instance from * concurrent access: thread status and ring access (when pushing responses). * * Here's how the call graph is supposed to be for a single I/O: * * xbdback_co_main() * | * | --> xbdback_co_cache_doflush() or NULL * | | * | - xbdback_co_cache_flush2() <- xbdback_co_do_io() <- * | | | * | |-> xbdback_co_cache_flush() -> xbdback_co_map_io()- * xbdback_co_main_loop()-| * | |-> xbdback_co_main_done() ---> xbdback_co_map_io()- * | | | * | -- xbdback_co_main_done2() <-- xbdback_co_do_io() <- * | | * | --> xbdback_co_main() or NULL * | * xbdback_co_io() -> xbdback_co_main_incr() -> xbdback_co_main_loop() * | * xbdback_co_io_gotreq()--+--> xbdback_co_map_io() --- * | | | * -> xbdback_co_io_loop()----| <- xbdback_co_do_io() <-- * | | | | * | | | |----------> xbdback_co_io_gotio() * | | | | * | | xbdback_co_main_incr() | * | | | | * | | xbdback_co_main_loop() | * | | | * | xbdback_co_io_gotio2() <-----------| * | | | * | | |----------> xbdback_co_io_gotfrag() * | | | * -- xbdback_co_io_gotfrag2() <---------| * | * xbdback_co_main_incr() -> xbdback_co_main_loop() */ typedef void *(* xbdback_cont_t)(struct xbdback_instance *, void *); enum xbdi_proto { XBDIP_NATIVE, XBDIP_32, XBDIP_64 }; /* we keep the xbdback instances in a linked list */ struct xbdback_instance { SLIST_ENTRY(xbdback_instance) next; struct xenbus_device *xbdi_xbusd; /* our xenstore entry */ struct xenbus_watch xbdi_watch; /* to watch our store */ domid_t xbdi_domid; /* attached to this domain */ uint32_t xbdi_handle; /* domain-specific handle */ char xbdi_name[16]; /* name of this instance */ /* mutex that protects concurrent access to the xbdback instance */ kmutex_t xbdi_lock; kcondvar_t xbdi_cv; /* wait channel for thread work */ xbdback_state_t xbdi_status; /* thread's status */ /* backing device parameters */ dev_t xbdi_dev; const struct bdevsw *xbdi_bdevsw; /* pointer to the device's bdevsw */ struct vnode *xbdi_vp; uint64_t xbdi_size; bool xbdi_ro; /* is device read-only ? */ /* parameters for the communication */ unsigned int xbdi_evtchn; /* private parameters for communication */ blkif_back_ring_proto_t xbdi_ring; enum xbdi_proto xbdi_proto; grant_handle_t xbdi_ring_handle; /* to unmap the ring */ vaddr_t xbdi_ring_va; /* to unmap the ring */ /* disconnection must be postponed until all I/O is done */ int xbdi_refcnt; /* * State for I/O processing/coalescing follows; this has to * live here instead of on the stack because of the * continuation-ness (see above). */ RING_IDX xbdi_req_prod; /* limit on request indices */ xbdback_cont_t xbdi_cont, xbdi_cont_aux; SIMPLEQ_ENTRY(xbdback_instance) xbdi_on_hold; /* waiting on resources */ /* _request state: track requests fetched from ring */ struct xbdback_request *xbdi_req; /* if NULL, ignore following */ blkif_request_t xbdi_xen_req; int xbdi_segno; /* _io state: I/O associated to this instance */ struct xbdback_io *xbdi_io; /* if NULL, ignore next field */ daddr_t xbdi_next_sector; uint8_t xbdi_last_fs, xbdi_this_fs; /* first sectors */ uint8_t xbdi_last_ls, xbdi_this_ls; /* last sectors */ grant_ref_t xbdi_thisgrt, xbdi_lastgrt; /* grants */ /* other state */ int xbdi_same_page; /* are we merging two segments on the same page? */ uint xbdi_pendingreqs; /* number of I/O in fly */ struct timeval xbdi_lasterr_time; /* error time tracking */ #ifdef DEBUG struct timeval xbdi_lastfragio_time; /* fragmented I/O tracking */ #endif }; /* Manipulation of the above reference count. */ #define xbdi_get(xbdip) atomic_inc_uint(&(xbdip)->xbdi_refcnt) #define xbdi_put(xbdip) \ do { \ if (atomic_dec_uint_nv(&(xbdip)->xbdi_refcnt) == 0) \ xbdback_finish_disconnect(xbdip); \ } while (/* CONSTCOND */ 0) SLIST_HEAD(, xbdback_instance) xbdback_instances; /* * For each request from a guest, a xbdback_request is allocated from * a pool. This will describe the request until completion. The * request may require multiple IO operations to perform, so the * per-IO information is not stored here. */ struct xbdback_request { struct xbdback_instance *rq_xbdi; /* our xbd instance */ uint64_t rq_id; int rq_iocount; /* reference count; or, number of outstanding I/O's */ int rq_ioerrs; uint8_t rq_operation; }; /* * For each I/O operation associated with one of those requests, an * xbdback_io is allocated from a pool. It may correspond to multiple * Xen disk requests, or parts of them, if several arrive at once that * can be coalesced. */ struct xbdback_io { /* The instance pointer is duplicated for convenience. */ struct xbdback_instance *xio_xbdi; /* our xbd instance */ uint8_t xio_operation; union { struct { struct buf xio_buf; /* our I/O */ /* xbd requests involved */ SLIST_HEAD(, xbdback_fragment) xio_rq; /* the virtual address to map the request at */ vaddr_t xio_vaddr; /* grants to map */ grant_ref_t xio_gref[XENSHM_MAX_PAGES_PER_REQUEST]; /* grants release */ grant_handle_t xio_gh[XENSHM_MAX_PAGES_PER_REQUEST]; uint16_t xio_nrma; /* number of guest pages */ uint16_t xio_mapped; /* == 1: grants are mapped */ } xio_rw; uint64_t xio_flush_id; } u; }; #define xio_buf u.xio_rw.xio_buf #define xio_rq u.xio_rw.xio_rq #define xio_vaddr u.xio_rw.xio_vaddr #define xio_gref u.xio_rw.xio_gref #define xio_gh u.xio_rw.xio_gh #define xio_nrma u.xio_rw.xio_nrma #define xio_mapped u.xio_rw.xio_mapped #define xio_flush_id u.xio_flush_id /* * Rather than having the xbdback_io keep an array of the * xbdback_requests involved, since the actual number will probably be * small but might be as large as BLKIF_RING_SIZE, use a list. This * would be threaded through xbdback_request, but one of them might be * part of multiple I/O's, alas. */ struct xbdback_fragment { struct xbdback_request *car; SLIST_ENTRY(xbdback_fragment) cdr; }; /* * Pools to manage the chain of block requests and I/Os fragments * submitted by frontend. */ struct xbdback_pool { struct pool_cache pc; struct timeval last_warning; } xbdback_request_pool, xbdback_io_pool, xbdback_fragment_pool; SIMPLEQ_HEAD(xbdback_iqueue, xbdback_instance); static struct xbdback_iqueue xbdback_shmq; static int xbdback_shmcb; /* have we already registered a callback? */ /* Interval between reports of I/O errors from frontend */ struct timeval xbdback_err_intvl = { 1, 0 }; #ifdef DEBUG struct timeval xbdback_fragio_intvl = { 60, 0 }; #endif void xbdbackattach(int); static int xbdback_xenbus_create(struct xenbus_device *); static int xbdback_xenbus_destroy(void *); static void xbdback_frontend_changed(void *, XenbusState); static void xbdback_backend_changed(struct xenbus_watch *, const char **, unsigned int); static int xbdback_evthandler(void *); static int xbdback_connect(struct xbdback_instance *); static void xbdback_disconnect(struct xbdback_instance *); static void xbdback_finish_disconnect(struct xbdback_instance *); static struct xbdback_instance *xbdif_lookup(domid_t, uint32_t); static void *xbdback_co_main(struct xbdback_instance *, void *); static void *xbdback_co_main_loop(struct xbdback_instance *, void *); static void *xbdback_co_main_incr(struct xbdback_instance *, void *); static void *xbdback_co_main_done(struct xbdback_instance *, void *); static void *xbdback_co_main_done2(struct xbdback_instance *, void *); static void *xbdback_co_cache_flush(struct xbdback_instance *, void *); static void *xbdback_co_cache_flush2(struct xbdback_instance *, void *); static void *xbdback_co_cache_doflush(struct xbdback_instance *, void *); static void *xbdback_co_io(struct xbdback_instance *, void *); static void *xbdback_co_io_gotreq(struct xbdback_instance *, void *); static void *xbdback_co_io_loop(struct xbdback_instance *, void *); static void *xbdback_co_io_gotio(struct xbdback_instance *, void *); static void *xbdback_co_io_gotio2(struct xbdback_instance *, void *); static void *xbdback_co_io_gotfrag(struct xbdback_instance *, void *); static void *xbdback_co_io_gotfrag2(struct xbdback_instance *, void *); static void *xbdback_co_map_io(struct xbdback_instance *, void *); static void *xbdback_co_do_io(struct xbdback_instance *, void *); static void *xbdback_co_wait_shm_callback(struct xbdback_instance *, void *); static int xbdback_shm_callback(void *); static void xbdback_io_error(struct xbdback_io *, int); static void xbdback_iodone(struct buf *); static void xbdback_send_reply(struct xbdback_instance *, uint64_t , int , int); static void *xbdback_map_shm(struct xbdback_io *); static void xbdback_unmap_shm(struct xbdback_io *); static void *xbdback_pool_get(struct xbdback_pool *, struct xbdback_instance *); static void xbdback_pool_put(struct xbdback_pool *, void *); static void xbdback_thread(void *); static void xbdback_wakeup_thread(struct xbdback_instance *); static void xbdback_trampoline(struct xbdback_instance *, void *); static struct xenbus_backend_driver xbd_backend_driver = { .xbakd_create = xbdback_xenbus_create, .xbakd_type = "vbd" }; void xbdbackattach(int n) { XENPRINTF(("xbdbackattach\n")); /* * initialize the backend driver, register the control message handler * and send driver up message. */ SLIST_INIT(&xbdback_instances); SIMPLEQ_INIT(&xbdback_shmq); xbdback_shmcb = 0; pool_cache_bootstrap(&xbdback_request_pool.pc, sizeof(struct xbdback_request), 0, 0, 0, "xbbrp", NULL, IPL_SOFTBIO, NULL, NULL, NULL); pool_cache_bootstrap(&xbdback_io_pool.pc, sizeof(struct xbdback_io), 0, 0, 0, "xbbip", NULL, IPL_SOFTBIO, NULL, NULL, NULL); pool_cache_bootstrap(&xbdback_fragment_pool.pc, sizeof(struct xbdback_fragment), 0, 0, 0, "xbbfp", NULL, IPL_SOFTBIO, NULL, NULL, NULL); /* we allocate enough to handle a whole ring at once */ if (pool_prime(&xbdback_request_pool.pc.pc_pool, BLKIF_RING_SIZE) != 0) printf("xbdback: failed to prime request pool\n"); if (pool_prime(&xbdback_io_pool.pc.pc_pool, BLKIF_RING_SIZE) != 0) printf("xbdback: failed to prime io pool\n"); if (pool_prime(&xbdback_fragment_pool.pc.pc_pool, BLKIF_MAX_SEGMENTS_PER_REQUEST * BLKIF_RING_SIZE) != 0) printf("xbdback: failed to prime fragment pool\n"); xenbus_backend_register(&xbd_backend_driver); } static int xbdback_xenbus_create(struct xenbus_device *xbusd) { struct xbdback_instance *xbdi; long domid, handle; int error, i; char *ep; if ((error = xenbus_read_ul(NULL, xbusd->xbusd_path, "frontend-id", &domid, 10)) != 0) { aprint_error("xbdback: can't read %s/frontend-id: %d\n", xbusd->xbusd_path, error); return error; } /* * get handle: this is the last component of the path; which is * a decimal number. $path/dev contains the device name, which is not * appropriate. */ for (i = strlen(xbusd->xbusd_path); i > 0; i--) { if (xbusd->xbusd_path[i] == '/') break; } if (i == 0) { aprint_error("xbdback: can't parse %s\n", xbusd->xbusd_path); return EFTYPE; } handle = strtoul(&xbusd->xbusd_path[i+1], &ep, 10); if (*ep != '\0') { aprint_error("xbdback: can't parse %s\n", xbusd->xbusd_path); return EFTYPE; } if (xbdif_lookup(domid, handle) != NULL) { return EEXIST; } xbdi = kmem_zalloc(sizeof(*xbdi), KM_SLEEP); xbdi->xbdi_domid = domid; xbdi->xbdi_handle = handle; snprintf(xbdi->xbdi_name, sizeof(xbdi->xbdi_name), "xbdb%di%d", xbdi->xbdi_domid, xbdi->xbdi_handle); /* initialize status and reference counter */ xbdi->xbdi_status = DISCONNECTED; xbdi_get(xbdi); mutex_init(&xbdi->xbdi_lock, MUTEX_DEFAULT, IPL_BIO); cv_init(&xbdi->xbdi_cv, xbdi->xbdi_name); SLIST_INSERT_HEAD(&xbdback_instances, xbdi, next); xbusd->xbusd_u.b.b_cookie = xbdi; xbusd->xbusd_u.b.b_detach = xbdback_xenbus_destroy; xbusd->xbusd_otherend_changed = xbdback_frontend_changed; xbdi->xbdi_xbusd = xbusd; error = xenbus_watch_path2(xbusd, xbusd->xbusd_path, "physical-device", &xbdi->xbdi_watch, xbdback_backend_changed); if (error) { printf("failed to watch on %s/physical-device: %d\n", xbusd->xbusd_path, error); goto fail; } xbdi->xbdi_watch.xbw_dev = xbusd; error = xenbus_switch_state(xbusd, NULL, XenbusStateInitWait); if (error) { printf("failed to switch state on %s: %d\n", xbusd->xbusd_path, error); goto fail2; } return 0; fail2: unregister_xenbus_watch(&xbdi->xbdi_watch); fail: kmem_free(xbdi, sizeof(*xbdi)); return error; } static int xbdback_xenbus_destroy(void *arg) { struct xbdback_instance *xbdi = arg; struct xenbus_device *xbusd = xbdi->xbdi_xbusd; struct gnttab_unmap_grant_ref ungrop; int err; XENPRINTF(("xbdback_xenbus_destroy state %d\n", xbdi->xbdi_status)); xbdback_disconnect(xbdi); /* unregister watch */ if (xbdi->xbdi_watch.node) { unregister_xenbus_watch(&xbdi->xbdi_watch); free(xbdi->xbdi_watch.node, M_DEVBUF); xbdi->xbdi_watch.node = NULL; } /* unmap ring */ if (xbdi->xbdi_ring_va != 0) { ungrop.host_addr = xbdi->xbdi_ring_va; ungrop.handle = xbdi->xbdi_ring_handle; ungrop.dev_bus_addr = 0; err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &ungrop, 1); if (err) printf("xbdback %s: unmap_grant_ref failed: %d\n", xbusd->xbusd_otherend, err); uvm_km_free(kernel_map, xbdi->xbdi_ring_va, PAGE_SIZE, UVM_KMF_VAONLY); } /* close device */ if (xbdi->xbdi_size) { const char *name; struct dkwedge_info wi; if (getdiskinfo(xbdi->xbdi_vp, &wi) == 0) name = wi.dkw_devname; else name = "*unknown*"; printf("xbd backend: detach device %s for domain %d\n", name, xbdi->xbdi_domid); vn_close(xbdi->xbdi_vp, FREAD, NOCRED); } SLIST_REMOVE(&xbdback_instances, xbdi, xbdback_instance, next); mutex_destroy(&xbdi->xbdi_lock); cv_destroy(&xbdi->xbdi_cv); kmem_free(xbdi, sizeof(*xbdi)); return 0; } static int xbdback_connect(struct xbdback_instance *xbdi) { int len, err; struct gnttab_map_grant_ref grop; struct gnttab_unmap_grant_ref ungrop; evtchn_op_t evop; u_long ring_ref, revtchn; char *xsproto; const char *proto; struct xenbus_device *xbusd = xbdi->xbdi_xbusd; XENPRINTF(("xbdback %s: connect\n", xbusd->xbusd_path)); /* read comunication informations */ err = xenbus_read_ul(NULL, xbusd->xbusd_otherend, "ring-ref", &ring_ref, 10); if (err) { xenbus_dev_fatal(xbusd, err, "reading %s/ring-ref", xbusd->xbusd_otherend); return -1; } XENPRINTF(("xbdback %s: connect ring-ref %lu\n", xbusd->xbusd_path, ring_ref)); err = xenbus_read_ul(NULL, xbusd->xbusd_otherend, "event-channel", &revtchn, 10); if (err) { xenbus_dev_fatal(xbusd, err, "reading %s/event-channel", xbusd->xbusd_otherend); return -1; } XENPRINTF(("xbdback %s: connect revtchn %lu\n", xbusd->xbusd_path, revtchn)); err = xenbus_read(NULL, xbusd->xbusd_otherend, "protocol", &len, &xsproto); if (err) { xbdi->xbdi_proto = XBDIP_NATIVE; proto = "unspecified"; XENPRINTF(("xbdback %s: connect no xsproto\n", xbusd->xbusd_path)); } else { XENPRINTF(("xbdback %s: connect xsproto %s\n", xbusd->xbusd_path, xsproto)); if (strcmp(xsproto, XEN_IO_PROTO_ABI_NATIVE) == 0) { xbdi->xbdi_proto = XBDIP_NATIVE; proto = XEN_IO_PROTO_ABI_NATIVE; } else if (strcmp(xsproto, XEN_IO_PROTO_ABI_X86_32) == 0) { xbdi->xbdi_proto = XBDIP_32; proto = XEN_IO_PROTO_ABI_X86_32; } else if (strcmp(xsproto, XEN_IO_PROTO_ABI_X86_64) == 0) { xbdi->xbdi_proto = XBDIP_64; proto = XEN_IO_PROTO_ABI_X86_64; } else { aprint_error("xbd domain %d: unknown proto %s\n", xbdi->xbdi_domid, xsproto); free(xsproto, M_DEVBUF); return -1; } free(xsproto, M_DEVBUF); } /* allocate VA space and map rings */ xbdi->xbdi_ring_va = uvm_km_alloc(kernel_map, PAGE_SIZE, 0, UVM_KMF_VAONLY); if (xbdi->xbdi_ring_va == 0) { xenbus_dev_fatal(xbusd, ENOMEM, "can't get VA for ring", xbusd->xbusd_otherend); return -1; } XENPRINTF(("xbdback %s: connect va 0x%" PRIxVADDR "\n", xbusd->xbusd_path, xbdi->xbdi_ring_va)); grop.host_addr = xbdi->xbdi_ring_va; grop.flags = GNTMAP_host_map; grop.ref = ring_ref; grop.dom = xbdi->xbdi_domid; err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &grop, 1); if (err || grop.status) { aprint_error("xbdback %s: can't map grant ref: %d/%d\n", xbusd->xbusd_path, err, grop.status); xenbus_dev_fatal(xbusd, EINVAL, "can't map ring", xbusd->xbusd_otherend); goto err; } xbdi->xbdi_ring_handle = grop.handle; XENPRINTF(("xbdback %s: connect grhandle %d\n", xbusd->xbusd_path, grop.handle)); switch(xbdi->xbdi_proto) { case XBDIP_NATIVE: { blkif_sring_t *sring = (void *)xbdi->xbdi_ring_va; BACK_RING_INIT(&xbdi->xbdi_ring.ring_n, sring, PAGE_SIZE); break; } case XBDIP_32: { blkif_x86_32_sring_t *sring = (void *)xbdi->xbdi_ring_va; BACK_RING_INIT(&xbdi->xbdi_ring.ring_32, sring, PAGE_SIZE); break; } case XBDIP_64: { blkif_x86_64_sring_t *sring = (void *)xbdi->xbdi_ring_va; BACK_RING_INIT(&xbdi->xbdi_ring.ring_64, sring, PAGE_SIZE); break; } } evop.cmd = EVTCHNOP_bind_interdomain; evop.u.bind_interdomain.remote_dom = xbdi->xbdi_domid; evop.u.bind_interdomain.remote_port = revtchn; err = HYPERVISOR_event_channel_op(&evop); if (err) { aprint_error("blkback %s: " "can't get event channel: %d\n", xbusd->xbusd_otherend, err); xenbus_dev_fatal(xbusd, err, "can't bind event channel", xbusd->xbusd_otherend); goto err2; } XENPRINTF(("xbdback %s: connect evchannel %d\n", xbusd->xbusd_path, xbdi->xbdi_evtchn)); xbdi->xbdi_evtchn = evop.u.bind_interdomain.local_port; event_set_handler(xbdi->xbdi_evtchn, xbdback_evthandler, xbdi, IPL_BIO, xbdi->xbdi_name); aprint_verbose("xbd backend domain %d handle %#x (%d) " "using event channel %d, protocol %s\n", xbdi->xbdi_domid, xbdi->xbdi_handle, xbdi->xbdi_handle, xbdi->xbdi_evtchn, proto); /* enable the xbdback event handler machinery */ xbdi->xbdi_status = WAITING; hypervisor_enable_event(xbdi->xbdi_evtchn); hypervisor_notify_via_evtchn(xbdi->xbdi_evtchn); if (kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, xbdback_thread, xbdi, NULL, "%s", xbdi->xbdi_name) == 0) return 0; err2: /* unmap ring */ ungrop.host_addr = xbdi->xbdi_ring_va; ungrop.handle = xbdi->xbdi_ring_handle; ungrop.dev_bus_addr = 0; err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &ungrop, 1); if (err) aprint_error("xbdback %s: unmap_grant_ref failed: %d\n", xbusd->xbusd_path, err); err: /* free ring VA space */ uvm_km_free(kernel_map, xbdi->xbdi_ring_va, PAGE_SIZE, UVM_KMF_VAONLY); return -1; } /* * Signal a xbdback thread to disconnect. Done in 'xenwatch' thread context. */ static void xbdback_disconnect(struct xbdback_instance *xbdi) { mutex_enter(&xbdi->xbdi_lock); if (xbdi->xbdi_status == DISCONNECTED) { mutex_exit(&xbdi->xbdi_lock); return; } hypervisor_mask_event(xbdi->xbdi_evtchn); event_remove_handler(xbdi->xbdi_evtchn, xbdback_evthandler, xbdi); /* signal thread that we want to disconnect, then wait for it */ xbdi->xbdi_status = DISCONNECTING; cv_signal(&xbdi->xbdi_cv); while (xbdi->xbdi_status != DISCONNECTED) cv_wait(&xbdi->xbdi_cv, &xbdi->xbdi_lock); mutex_exit(&xbdi->xbdi_lock); xenbus_switch_state(xbdi->xbdi_xbusd, NULL, XenbusStateClosing); } static void xbdback_frontend_changed(void *arg, XenbusState new_state) { struct xbdback_instance *xbdi = arg; struct xenbus_device *xbusd = xbdi->xbdi_xbusd; XENPRINTF(("xbdback %s: new state %d\n", xbusd->xbusd_path, new_state)); switch(new_state) { case XenbusStateInitialising: break; case XenbusStateInitialised: case XenbusStateConnected: if (xbdi->xbdi_status == WAITING || xbdi->xbdi_status == RUN) break; xbdback_connect(xbdi); break; case XenbusStateClosing: xbdback_disconnect(xbdi); break; case XenbusStateClosed: /* otherend_changed() should handle it for us */ panic("xbdback_frontend_changed: closed\n"); case XenbusStateUnknown: case XenbusStateInitWait: default: aprint_error("xbdback %s: invalid frontend state %d\n", xbusd->xbusd_path, new_state); } return; } static void xbdback_backend_changed(struct xenbus_watch *watch, const char **vec, unsigned int len) { struct xenbus_device *xbusd = watch->xbw_dev; struct xbdback_instance *xbdi = xbusd->xbusd_u.b.b_cookie; int err; long dev; char *mode; struct xenbus_transaction *xbt; const char *devname; int major; err = xenbus_read_ul(NULL, xbusd->xbusd_path, "physical-device", &dev, 10); /* * An error can occur as the watch can fire up just after being * registered. So we have to ignore error :( */ if (err) return; /* * we can also fire up after having opened the device, don't try * to do it twice. */ if (xbdi->xbdi_vp != NULL) { if (xbdi->xbdi_status == WAITING || xbdi->xbdi_status == RUN) { if (xbdi->xbdi_dev != dev) { printf("xbdback %s: changing physical device " "from %#"PRIx64" to %#lx not supported\n", xbusd->xbusd_path, xbdi->xbdi_dev, dev); } } return; } xbdi->xbdi_dev = dev; err = xenbus_read(NULL, xbusd->xbusd_path, "mode", NULL, &mode); if (err) { printf("xbdback: failed to read %s/mode: %d\n", xbusd->xbusd_path, err); return; } if (mode[0] == 'w') xbdi->xbdi_ro = false; else xbdi->xbdi_ro = true; free(mode, M_DEVBUF); major = major(xbdi->xbdi_dev); devname = devsw_blk2name(major); if (devname == NULL) { printf("xbdback %s: unknown device 0x%"PRIx64"\n", xbusd->xbusd_path, xbdi->xbdi_dev); return; } xbdi->xbdi_bdevsw = bdevsw_lookup(xbdi->xbdi_dev); if (xbdi->xbdi_bdevsw == NULL) { printf("xbdback %s: no bdevsw for device 0x%"PRIx64"\n", xbusd->xbusd_path, xbdi->xbdi_dev); return; } err = bdevvp(xbdi->xbdi_dev, &xbdi->xbdi_vp); if (err) { printf("xbdback %s: can't open device 0x%"PRIx64": %d\n", xbusd->xbusd_path, xbdi->xbdi_dev, err); return; } err = vn_lock(xbdi->xbdi_vp, LK_EXCLUSIVE | LK_RETRY); if (err) { printf("xbdback %s: can't vn_lock device 0x%"PRIx64": %d\n", xbusd->xbusd_path, xbdi->xbdi_dev, err); vrele(xbdi->xbdi_vp); return; } err = VOP_OPEN(xbdi->xbdi_vp, FREAD, NOCRED); if (err) { printf("xbdback %s: can't VOP_OPEN device 0x%"PRIx64": %d\n", xbusd->xbusd_path, xbdi->xbdi_dev, err); vput(xbdi->xbdi_vp); return; } VOP_UNLOCK(xbdi->xbdi_vp); /* dk device; get wedge data */ struct dkwedge_info wi; if ((err = getdiskinfo(xbdi->xbdi_vp, &wi)) == 0) { xbdi->xbdi_size = wi.dkw_size; printf("xbd backend: attach device %s (size %" PRIu64 ") " "for domain %d\n", wi.dkw_devname, xbdi->xbdi_size, xbdi->xbdi_domid); } else { /* If both Ioctls failed set device size to 0 and return */ printf("xbdback %s: can't DIOCGWEDGEINFO device " "0x%"PRIx64": %d\n", xbusd->xbusd_path, xbdi->xbdi_dev, err); xbdi->xbdi_size = xbdi->xbdi_dev = 0; vn_close(xbdi->xbdi_vp, FREAD, NOCRED); xbdi->xbdi_vp = NULL; return; } again: xbt = xenbus_transaction_start(); if (xbt == NULL) { printf("xbdback %s: can't start transaction\n", xbusd->xbusd_path); return; } err = xenbus_printf(xbt, xbusd->xbusd_path, "sectors", "%" PRIu64 , xbdi->xbdi_size); if (err) { printf("xbdback: failed to write %s/sectors: %d\n", xbusd->xbusd_path, err); goto abort; } err = xenbus_printf(xbt, xbusd->xbusd_path, "info", "%u", xbdi->xbdi_ro ? VDISK_READONLY : 0); if (err) { printf("xbdback: failed to write %s/info: %d\n", xbusd->xbusd_path, err); goto abort; } err = xenbus_printf(xbt, xbusd->xbusd_path, "sector-size", "%lu", (u_long)DEV_BSIZE); if (err) { printf("xbdback: failed to write %s/sector-size: %d\n", xbusd->xbusd_path, err); goto abort; } err = xenbus_printf(xbt, xbusd->xbusd_path, "feature-flush-cache", "%u", 1); if (err) { printf("xbdback: failed to write %s/feature-flush-cache: %d\n", xbusd->xbusd_path, err); goto abort; } err = xenbus_transaction_end(xbt, 0); if (err == EAGAIN) goto again; if (err) { printf("xbdback %s: can't end transaction: %d\n", xbusd->xbusd_path, err); } err = xenbus_switch_state(xbusd, NULL, XenbusStateConnected); if (err) { printf("xbdback %s: can't switch state: %d\n", xbusd->xbusd_path, err); } return; abort: xenbus_transaction_end(xbt, 1); } /* * Used by a xbdi thread to signal that it is now disconnected. */ static void xbdback_finish_disconnect(struct xbdback_instance *xbdi) { KASSERT(mutex_owned(&xbdi->xbdi_lock)); KASSERT(xbdi->xbdi_status == DISCONNECTING); xbdi->xbdi_status = DISCONNECTED; cv_signal(&xbdi->xbdi_cv); } static struct xbdback_instance * xbdif_lookup(domid_t dom , uint32_t handle) { struct xbdback_instance *xbdi; SLIST_FOREACH(xbdi, &xbdback_instances, next) { if (xbdi->xbdi_domid == dom && xbdi->xbdi_handle == handle) return xbdi; } return NULL; } static int xbdback_evthandler(void *arg) { struct xbdback_instance *xbdi = arg; XENPRINTF(("xbdback_evthandler domain %d: cont %p\n", xbdi->xbdi_domid, xbdi->xbdi_cont)); xbdback_wakeup_thread(xbdi); return 1; } /* * Main thread routine for one xbdback instance. Woken up by * xbdback_evthandler when a domain has I/O work scheduled in a I/O ring. */ static void xbdback_thread(void *arg) { struct xbdback_instance *xbdi = arg; for (;;) { mutex_enter(&xbdi->xbdi_lock); switch (xbdi->xbdi_status) { case WAITING: cv_wait(&xbdi->xbdi_cv, &xbdi->xbdi_lock); mutex_exit(&xbdi->xbdi_lock); break; case RUN: xbdi->xbdi_status = WAITING; /* reset state */ mutex_exit(&xbdi->xbdi_lock); if (xbdi->xbdi_cont == NULL) { xbdi->xbdi_cont = xbdback_co_main; } xbdback_trampoline(xbdi, xbdi); break; case DISCONNECTING: if (xbdi->xbdi_pendingreqs > 0) { /* there are pending I/Os. Wait for them. */ cv_wait(&xbdi->xbdi_cv, &xbdi->xbdi_lock); mutex_exit(&xbdi->xbdi_lock); break; } /* All I/Os should have been processed by now, * xbdi_refcnt should drop to 0 */ xbdi_put(xbdi); KASSERT(xbdi->xbdi_refcnt == 0); mutex_exit(&xbdi->xbdi_lock); kthread_exit(0); break; default: panic("%s: invalid state %d", xbdi->xbdi_name, xbdi->xbdi_status); } } } static void * xbdback_co_main(struct xbdback_instance *xbdi, void *obj) { (void)obj; xbdi->xbdi_req_prod = xbdi->xbdi_ring.ring_n.sring->req_prod; xen_rmb(); /* ensure we see all requests up to req_prod */ /* * note that we'll eventually get a full ring of request. * in this case, MASK_BLKIF_IDX(req_cons) == MASK_BLKIF_IDX(req_prod) */ xbdi->xbdi_cont = xbdback_co_main_loop; return xbdi; } /* * Fetch a blkif request from the ring, and pass control to the appropriate * continuation. * If someone asked for disconnection, do not fetch any more request from * the ring. */ static void * xbdback_co_main_loop(struct xbdback_instance *xbdi, void *obj) { blkif_request_t *req; blkif_x86_32_request_t *req32; blkif_x86_64_request_t *req64; (void)obj; req = &xbdi->xbdi_xen_req; if (xbdi->xbdi_ring.ring_n.req_cons != xbdi->xbdi_req_prod) { switch(xbdi->xbdi_proto) { case XBDIP_NATIVE: memcpy(req, RING_GET_REQUEST(&xbdi->xbdi_ring.ring_n, xbdi->xbdi_ring.ring_n.req_cons), sizeof(blkif_request_t)); break; case XBDIP_32: req32 = RING_GET_REQUEST(&xbdi->xbdi_ring.ring_32, xbdi->xbdi_ring.ring_n.req_cons); req->operation = req32->operation; req->nr_segments = req32->nr_segments; req->handle = req32->handle; req->id = req32->id; req->sector_number = req32->sector_number; break; case XBDIP_64: req64 = RING_GET_REQUEST(&xbdi->xbdi_ring.ring_64, xbdi->xbdi_ring.ring_n.req_cons); req->operation = req64->operation; req->nr_segments = req64->nr_segments; req->handle = req64->handle; req->id = req64->id; req->sector_number = req64->sector_number; break; } __insn_barrier(); XENPRINTF(("xbdback op %d req_cons 0x%x req_prod 0x%x " "resp_prod 0x%x id %" PRIu64 "\n", req->operation, xbdi->xbdi_ring.ring_n.req_cons, xbdi->xbdi_req_prod, xbdi->xbdi_ring.ring_n.rsp_prod_pvt, req->id)); switch(req->operation) { case BLKIF_OP_READ: case BLKIF_OP_WRITE: xbdi->xbdi_cont = xbdback_co_io; break; case BLKIF_OP_FLUSH_DISKCACHE: xbdi_get(xbdi); xbdi->xbdi_cont = xbdback_co_cache_flush; break; default: if (ratecheck(&xbdi->xbdi_lasterr_time, &xbdback_err_intvl)) { printf("%s: unknown operation %d\n", xbdi->xbdi_name, req->operation); } xbdback_send_reply(xbdi, req->id, req->operation, BLKIF_RSP_ERROR); xbdi->xbdi_cont = xbdback_co_main_incr; break; } } else { xbdi->xbdi_cont = xbdback_co_main_done; } return xbdi; } /* * Increment consumer index and move on to the next request. In case * we want to disconnect, leave continuation now. */ static void * xbdback_co_main_incr(struct xbdback_instance *xbdi, void *obj) { (void)obj; blkif_back_ring_t *ring = &xbdi->xbdi_ring.ring_n; ring->req_cons++; /* * Do not bother with locking here when checking for xbdi_status: if * we get a transient state, we will get the right value at * the next increment. */ if (xbdi->xbdi_status == DISCONNECTING) xbdi->xbdi_cont = NULL; else xbdi->xbdi_cont = xbdback_co_main_loop; /* * Each time the thread processes a full ring of requests, give * a chance to other threads to process I/Os too */ if ((ring->req_cons % BLKIF_RING_SIZE) == 0) yield(); return xbdi; } /* * Ring processing is over. If there are any I/O still present for this * instance, handle them first. */ static void * xbdback_co_main_done(struct xbdback_instance *xbdi, void *obj) { (void)obj; if (xbdi->xbdi_io != NULL) { KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ || xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE); xbdi->xbdi_cont = xbdback_co_map_io; xbdi->xbdi_cont_aux = xbdback_co_main_done2; } else { xbdi->xbdi_cont = xbdback_co_main_done2; } return xbdi; } /* * Check for requests in the instance's ring. In case there are, start again * from the beginning. If not, stall. */ static void * xbdback_co_main_done2(struct xbdback_instance *xbdi, void *obj) { int work_to_do; RING_FINAL_CHECK_FOR_REQUESTS(&xbdi->xbdi_ring.ring_n, work_to_do); if (work_to_do) xbdi->xbdi_cont = xbdback_co_main; else xbdi->xbdi_cont = NULL; return xbdi; } /* * Frontend requested a cache flush operation. */ static void * xbdback_co_cache_flush(struct xbdback_instance *xbdi, void *obj) { (void)obj; XENPRINTF(("xbdback_co_cache_flush %p %p\n", xbdi, obj)); if (xbdi->xbdi_io != NULL) { /* Some I/Os are required for this instance. Process them. */ KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ || xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE); KASSERT(xbdi->xbdi_pendingreqs > 0); xbdi->xbdi_cont = xbdback_co_map_io; xbdi->xbdi_cont_aux = xbdback_co_cache_flush2; } else { xbdi->xbdi_cont = xbdback_co_cache_flush2; } return xbdi; } static void * xbdback_co_cache_flush2(struct xbdback_instance *xbdi, void *obj) { (void)obj; XENPRINTF(("xbdback_co_cache_flush2 %p %p\n", xbdi, obj)); if (xbdi->xbdi_pendingreqs > 0) { /* * There are pending requests. * Event or iodone() will restart processing */ xbdi->xbdi_cont = NULL; xbdi_put(xbdi); return NULL; } xbdi->xbdi_cont = xbdback_co_cache_doflush; return xbdback_pool_get(&xbdback_io_pool, xbdi); } /* Start the flush work */ static void * xbdback_co_cache_doflush(struct xbdback_instance *xbdi, void *obj) { struct xbdback_io *xbd_io; XENPRINTF(("xbdback_co_cache_doflush %p %p\n", xbdi, obj)); xbd_io = xbdi->xbdi_io = obj; xbd_io->xio_xbdi = xbdi; xbd_io->xio_operation = xbdi->xbdi_xen_req.operation; xbd_io->xio_flush_id = xbdi->xbdi_xen_req.id; xbdi->xbdi_cont = xbdback_co_do_io; return xbdi; } /* * A read or write I/O request must be processed. Do some checks first, * then get the segment information directly from the ring request. */ static void * xbdback_co_io(struct xbdback_instance *xbdi, void *obj) { int i, error; blkif_request_t *req; blkif_x86_32_request_t *req32; blkif_x86_64_request_t *req64; (void)obj; /* some sanity checks */ req = &xbdi->xbdi_xen_req; if (req->nr_segments < 1 || req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST) { if (ratecheck(&xbdi->xbdi_lasterr_time, &xbdback_err_intvl)) { printf("%s: invalid number of segments: %d\n", xbdi->xbdi_name, xbdi->xbdi_xen_req.nr_segments); } error = EINVAL; goto end; } KASSERT(req->operation == BLKIF_OP_READ || req->operation == BLKIF_OP_WRITE); if (req->operation == BLKIF_OP_WRITE) { if (xbdi->xbdi_ro) { error = EROFS; goto end; } } xbdi->xbdi_segno = 0; /* copy request segments */ switch(xbdi->xbdi_proto) { case XBDIP_NATIVE: /* already copied in xbdback_co_main_loop */ break; case XBDIP_32: req32 = RING_GET_REQUEST(&xbdi->xbdi_ring.ring_32, xbdi->xbdi_ring.ring_n.req_cons); for (i = 0; i < req->nr_segments; i++) req->seg[i] = req32->seg[i]; break; case XBDIP_64: req64 = RING_GET_REQUEST(&xbdi->xbdi_ring.ring_64, xbdi->xbdi_ring.ring_n.req_cons); for (i = 0; i < req->nr_segments; i++) req->seg[i] = req64->seg[i]; break; } xbdi->xbdi_cont = xbdback_co_io_gotreq; return xbdback_pool_get(&xbdback_request_pool, xbdi); end: xbdback_send_reply(xbdi, xbdi->xbdi_xen_req.id, xbdi->xbdi_xen_req.operation, error); xbdi->xbdi_cont = xbdback_co_main_incr; return xbdi; } /* * We have fetched segment requests from the ring. In case there are already * I/Os prepared for this instance, we can try coalescing the requests * with these I/Os. */ static void * xbdback_co_io_gotreq(struct xbdback_instance *xbdi, void *obj) { struct xbdback_request *xrq; xrq = xbdi->xbdi_req = obj; xrq->rq_xbdi = xbdi; xrq->rq_iocount = 0; xrq->rq_ioerrs = 0; xrq->rq_id = xbdi->xbdi_xen_req.id; xrq->rq_operation = xbdi->xbdi_xen_req.operation; KASSERT(xbdi->xbdi_req->rq_operation == BLKIF_OP_READ || xbdi->xbdi_req->rq_operation == BLKIF_OP_WRITE); /* * Request-level reasons not to coalesce: different device, * different op, or noncontiguous disk sectors (vs. previous * request handed to us). */ xbdi->xbdi_cont = xbdback_co_io_loop; if (xbdi->xbdi_io != NULL) { struct xbdback_request *last_req; last_req = SLIST_FIRST(&xbdi->xbdi_io->xio_rq)->car; XENPRINTF(("xbdback_io domain %d: hoping for sector %" PRIu64 "; got %" PRIu64 "\n", xbdi->xbdi_domid, xbdi->xbdi_next_sector, xbdi->xbdi_xen_req.sector_number)); if ((xrq->rq_operation != last_req->rq_operation) || (xbdi->xbdi_xen_req.sector_number != xbdi->xbdi_next_sector)) { XENPRINTF(("xbdback_io domain %d: segment break\n", xbdi->xbdi_domid)); xbdi->xbdi_next_sector = xbdi->xbdi_xen_req.sector_number; KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ || xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE); xbdi->xbdi_cont_aux = xbdback_co_io_loop; xbdi->xbdi_cont = xbdback_co_map_io; } } else { xbdi->xbdi_next_sector = xbdi->xbdi_xen_req.sector_number; } return xbdi; } /* Handle coalescing of multiple segment requests into one I/O work */ static void * xbdback_co_io_loop(struct xbdback_instance *xbdi, void *obj) { (void)obj; KASSERT(xbdi->xbdi_req->rq_operation == BLKIF_OP_READ || xbdi->xbdi_req->rq_operation == BLKIF_OP_WRITE); if (xbdi->xbdi_segno < xbdi->xbdi_xen_req.nr_segments) { uint8_t this_fs, this_ls, last_ls; grant_ref_t thisgrt; /* * Segment-level reason to coalesce: handling full * pages, or adjacent sector ranges from the same page * (and yes, this latter does happen). But not if the * array of client pseudo-physical pages is full. */ this_fs = xbdi->xbdi_xen_req.seg[xbdi->xbdi_segno].first_sect; this_ls = xbdi->xbdi_xen_req.seg[xbdi->xbdi_segno].last_sect; thisgrt = xbdi->xbdi_xen_req.seg[xbdi->xbdi_segno].gref; XENPRINTF(("xbdback_io domain %d: " "first,last_sect[%d]=0%o,0%o\n", xbdi->xbdi_domid, xbdi->xbdi_segno, this_fs, this_ls)); last_ls = xbdi->xbdi_last_ls = xbdi->xbdi_this_ls; xbdi->xbdi_this_fs = this_fs; xbdi->xbdi_this_ls = this_ls; xbdi->xbdi_thisgrt = thisgrt; if (xbdi->xbdi_io != NULL) { if (last_ls == VBD_MAXSECT && this_fs == 0 && xbdi->xbdi_io->xio_nrma < XENSHM_MAX_PAGES_PER_REQUEST) { xbdi->xbdi_same_page = 0; } else if (last_ls + 1 == this_fs #ifdef notyet && (last_fas & ~PAGE_MASK) == (this_fas & ~PAGE_MASK) #else && 0 /* can't know frame number yet */ #endif ) { #ifdef DEBUG if (ratecheck(&xbdi->xbdi_lastfragio_time, &xbdback_fragio_intvl)) printf("%s: domain is sending" " excessively fragmented I/O\n", xbdi->xbdi_name); #endif printf("xbdback_io: would maybe glue " "same page sec %d (%d->%d)\n", xbdi->xbdi_segno, this_fs, this_ls); XENPRINTF(("xbdback_io domain %d: glue same " "page", xbdi->xbdi_domid)); panic("notyet!"); xbdi->xbdi_same_page = 1; } else { KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ || xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE); xbdi->xbdi_cont_aux = xbdback_co_io_loop; xbdi->xbdi_cont = xbdback_co_map_io; return xbdi; } } else xbdi->xbdi_same_page = 0; if (xbdi->xbdi_io == NULL) { xbdi->xbdi_cont = xbdback_co_io_gotio; return xbdback_pool_get(&xbdback_io_pool, xbdi); } else { xbdi->xbdi_cont = xbdback_co_io_gotio2; } } else { /* done with the loop over segments; get next request */ xbdi->xbdi_cont = xbdback_co_main_incr; } return xbdi; } /* Prepare an I/O buffer for a xbdback instance */ static void * xbdback_co_io_gotio(struct xbdback_instance *xbdi, void *obj) { struct xbdback_io *xbd_io; vaddr_t start_offset; /* start offset in vm area */ int buf_flags; xbdi_get(xbdi); atomic_inc_uint(&xbdi->xbdi_pendingreqs); xbd_io = xbdi->xbdi_io = obj; buf_init(&xbd_io->xio_buf); xbd_io->xio_xbdi = xbdi; SLIST_INIT(&xbd_io->xio_rq); xbd_io->xio_nrma = 0; xbd_io->xio_mapped = 0; xbd_io->xio_operation = xbdi->xbdi_xen_req.operation; start_offset = xbdi->xbdi_this_fs * VBD_BSIZE; if (xbdi->xbdi_xen_req.operation == BLKIF_OP_WRITE) { buf_flags = B_WRITE; } else { buf_flags = B_READ; } xbd_io->xio_buf.b_flags = buf_flags; xbd_io->xio_buf.b_cflags = 0; xbd_io->xio_buf.b_oflags = 0; xbd_io->xio_buf.b_iodone = xbdback_iodone; xbd_io->xio_buf.b_proc = NULL; xbd_io->xio_buf.b_vp = xbdi->xbdi_vp; xbd_io->xio_buf.b_objlock = xbdi->xbdi_vp->v_interlock; xbd_io->xio_buf.b_dev = xbdi->xbdi_dev; xbd_io->xio_buf.b_blkno = xbdi->xbdi_next_sector; xbd_io->xio_buf.b_bcount = 0; xbd_io->xio_buf.b_data = (void *)start_offset; xbd_io->xio_buf.b_private = xbd_io; xbdi->xbdi_cont = xbdback_co_io_gotio2; return xbdi; } /* Manage fragments */ static void * xbdback_co_io_gotio2(struct xbdback_instance *xbdi, void *obj) { (void)obj; if (xbdi->xbdi_segno == 0 || SLIST_EMPTY(&xbdi->xbdi_io->xio_rq)) { /* if this is the first segment of a new request */ /* or if it's the first segment of the io */ xbdi->xbdi_cont = xbdback_co_io_gotfrag; return xbdback_pool_get(&xbdback_fragment_pool, xbdi); } xbdi->xbdi_cont = xbdback_co_io_gotfrag2; return xbdi; } /* Prepare the instance for its first fragment */ static void * xbdback_co_io_gotfrag(struct xbdback_instance *xbdi, void *obj) { struct xbdback_fragment *xbd_fr; xbd_fr = obj; xbd_fr->car = xbdi->xbdi_req; SLIST_INSERT_HEAD(&xbdi->xbdi_io->xio_rq, xbd_fr, cdr); ++xbdi->xbdi_req->rq_iocount; xbdi->xbdi_cont = xbdback_co_io_gotfrag2; return xbdi; } /* Last routine to manage segments fragments for one I/O */ static void * xbdback_co_io_gotfrag2(struct xbdback_instance *xbdi, void *obj) { struct xbdback_io *xbd_io; int seg_size; uint8_t this_fs, this_ls; this_fs = xbdi->xbdi_this_fs; this_ls = xbdi->xbdi_this_ls; xbd_io = xbdi->xbdi_io; seg_size = this_ls - this_fs + 1; if (seg_size < 0) { if (ratecheck(&xbdi->xbdi_lasterr_time, &xbdback_err_intvl)) { printf("xbdback_io domain %d: negative-size request " "(%d %d)\n", xbdi->xbdi_domid, this_ls, this_fs); } xbdback_io_error(xbdi->xbdi_io, EINVAL); xbdi->xbdi_io = NULL; xbdi->xbdi_cont = xbdback_co_main_incr; return xbdi; } if (!xbdi->xbdi_same_page) { XENPRINTF(("xbdback_io domain %d: appending grant %u\n", xbdi->xbdi_domid, (u_int)xbdi->xbdi_thisgrt)); xbd_io->xio_gref[xbd_io->xio_nrma++] = xbdi->xbdi_thisgrt; } xbd_io->xio_buf.b_bcount += (daddr_t)(seg_size * VBD_BSIZE); XENPRINTF(("xbdback_io domain %d: start sect %d size %d\n", xbdi->xbdi_domid, (int)xbdi->xbdi_next_sector, seg_size)); /* Finally, the end of the segment loop! */ xbdi->xbdi_next_sector += seg_size; ++xbdi->xbdi_segno; xbdi->xbdi_cont = xbdback_co_io_loop; return xbdi; } /* * Map the different I/O requests in backend's VA space. */ static void * xbdback_co_map_io(struct xbdback_instance *xbdi, void *obj) { (void)obj; XENPRINTF(("xbdback_io domain %d: flush sect %ld size %d ptr 0x%lx\n", xbdi->xbdi_domid, (long)xbdi->xbdi_io->xio_buf.b_blkno, (int)xbdi->xbdi_io->xio_buf.b_bcount, (long)xbdi->xbdi_io)); xbdi->xbdi_cont = xbdback_co_do_io; return xbdback_map_shm(xbdi->xbdi_io); } static void xbdback_io_error(struct xbdback_io *xbd_io, int error) { xbd_io->xio_buf.b_error = error; xbdback_iodone(&xbd_io->xio_buf); } /* * Main xbdback I/O routine. It can either perform a flush operation or * schedule a read/write operation. */ static void * xbdback_co_do_io(struct xbdback_instance *xbdi, void *obj) { struct xbdback_io *xbd_io = xbdi->xbdi_io; switch (xbd_io->xio_operation) { case BLKIF_OP_FLUSH_DISKCACHE: { int error; int force = 1; error = VOP_IOCTL(xbdi->xbdi_vp, DIOCCACHESYNC, &force, FWRITE, kauth_cred_get()); if (error) { aprint_error("xbdback %s: DIOCCACHESYNC returned %d\n", xbdi->xbdi_xbusd->xbusd_path, error); if (error == EOPNOTSUPP || error == ENOTTY) error = BLKIF_RSP_EOPNOTSUPP; else error = BLKIF_RSP_ERROR; } else error = BLKIF_RSP_OKAY; xbdback_send_reply(xbdi, xbd_io->xio_flush_id, xbd_io->xio_operation, error); xbdback_pool_put(&xbdback_io_pool, xbd_io); xbdi_put(xbdi); xbdi->xbdi_io = NULL; xbdi->xbdi_cont = xbdback_co_main_incr; return xbdi; } case BLKIF_OP_READ: case BLKIF_OP_WRITE: xbd_io->xio_buf.b_data = (void *) ((vaddr_t)xbd_io->xio_buf.b_data + xbd_io->xio_vaddr); #ifdef DIAGNOSTIC { vaddr_t bdata = (vaddr_t)xbd_io->xio_buf.b_data; int nsegs = ((((bdata + xbd_io->xio_buf.b_bcount - 1) & ~PAGE_MASK) - (bdata & ~PAGE_MASK)) >> PAGE_SHIFT) + 1; if ((bdata & ~PAGE_MASK) != (xbd_io->xio_vaddr & ~PAGE_MASK)) { printf("xbdback_co_do_io: vaddr %#" PRIxVADDR " bdata %#" PRIxVADDR "\n", xbd_io->xio_vaddr, bdata); panic("xbdback_co_do_io: bdata page change"); } if (nsegs > xbd_io->xio_nrma) { printf("xbdback_co_do_io: vaddr %#" PRIxVADDR " bcount %#x doesn't fit in %d pages\n", bdata, xbd_io->xio_buf.b_bcount, xbd_io->xio_nrma); panic("xbdback_co_do_io: not enough pages"); } } #endif if ((xbd_io->xio_buf.b_flags & B_READ) == 0) { mutex_enter(xbd_io->xio_buf.b_vp->v_interlock); xbd_io->xio_buf.b_vp->v_numoutput++; mutex_exit(xbd_io->xio_buf.b_vp->v_interlock); } bdev_strategy(&xbd_io->xio_buf); /* will call xbdback_iodone() asynchronously when done */ xbdi->xbdi_io = NULL; xbdi->xbdi_cont = xbdi->xbdi_cont_aux; return xbdi; default: /* Should never happen */ panic("xbdback_co_do_io: unsupported operation %d", xbd_io->xio_operation); } } /* * Called from softint(9) context when an I/O is done: for each request, send * back the associated reply to the domain. * * This gets reused by xbdback_io_error to report errors from other sources. */ static void xbdback_iodone(struct buf *bp) { struct xbdback_io *xbd_io; struct xbdback_instance *xbdi; int errp; xbd_io = bp->b_private; xbdi = xbd_io->xio_xbdi; XENPRINTF(("xbdback_io domain %d: iodone ptr 0x%lx\n", xbdi->xbdi_domid, (long)xbd_io)); if (xbd_io->xio_mapped == 1) xbdback_unmap_shm(xbd_io); if (bp->b_error != 0) { printf("xbd IO domain %d: error %d\n", xbdi->xbdi_domid, bp->b_error); errp = 1; } else errp = 0; /* for each constituent xbd request */ while(!SLIST_EMPTY(&xbd_io->xio_rq)) { struct xbdback_fragment *xbd_fr; struct xbdback_request *xbd_req; struct xbdback_instance *rxbdi __diagused; int error; xbd_fr = SLIST_FIRST(&xbd_io->xio_rq); xbd_req = xbd_fr->car; SLIST_REMOVE_HEAD(&xbd_io->xio_rq, cdr); xbdback_pool_put(&xbdback_fragment_pool, xbd_fr); if (errp) ++xbd_req->rq_ioerrs; /* finalize it only if this was its last I/O */ if (--xbd_req->rq_iocount > 0) continue; rxbdi = xbd_req->rq_xbdi; KASSERT(xbdi == rxbdi); error = xbd_req->rq_ioerrs > 0 ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY; XENPRINTF(("xbdback_io domain %d: end request %"PRIu64 "error=%d\n", xbdi->xbdi_domid, xbd_req->rq_id, error)); xbdback_send_reply(xbdi, xbd_req->rq_id, xbd_req->rq_operation, error); xbdback_pool_put(&xbdback_request_pool, xbd_req); } xbdi_put(xbdi); atomic_dec_uint(&xbdi->xbdi_pendingreqs); buf_destroy(&xbd_io->xio_buf); xbdback_pool_put(&xbdback_io_pool, xbd_io); xbdback_wakeup_thread(xbdi); } /* * Wake up the per xbdback instance thread. */ static void xbdback_wakeup_thread(struct xbdback_instance *xbdi) { mutex_enter(&xbdi->xbdi_lock); /* only set RUN state when we are WAITING for work */ if (xbdi->xbdi_status == WAITING) xbdi->xbdi_status = RUN; cv_broadcast(&xbdi->xbdi_cv); mutex_exit(&xbdi->xbdi_lock); } /* * called once a request has completed. Place the reply in the ring and * notify the guest OS. */ static void xbdback_send_reply(struct xbdback_instance *xbdi, uint64_t id, int op, int status) { blkif_response_t *resp_n; blkif_x86_32_response_t *resp32; blkif_x86_64_response_t *resp64; int notify; /* * The ring can be accessed by the xbdback thread, xbdback_iodone() * handler, or any handler that triggered the shm callback. So * protect ring access via the xbdi_lock mutex. */ mutex_enter(&xbdi->xbdi_lock); switch (xbdi->xbdi_proto) { case XBDIP_NATIVE: resp_n = RING_GET_RESPONSE(&xbdi->xbdi_ring.ring_n, xbdi->xbdi_ring.ring_n.rsp_prod_pvt); resp_n->id = id; resp_n->operation = op; resp_n->status = status; break; case XBDIP_32: resp32 = RING_GET_RESPONSE(&xbdi->xbdi_ring.ring_32, xbdi->xbdi_ring.ring_n.rsp_prod_pvt); resp32->id = id; resp32->operation = op; resp32->status = status; break; case XBDIP_64: resp64 = RING_GET_RESPONSE(&xbdi->xbdi_ring.ring_64, xbdi->xbdi_ring.ring_n.rsp_prod_pvt); resp64->id = id; resp64->operation = op; resp64->status = status; break; } xbdi->xbdi_ring.ring_n.rsp_prod_pvt++; RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&xbdi->xbdi_ring.ring_n, notify); mutex_exit(&xbdi->xbdi_lock); if (notify) { XENPRINTF(("xbdback_send_reply notify %d\n", xbdi->xbdi_domid)); hypervisor_notify_via_evtchn(xbdi->xbdi_evtchn); } } /* * Map multiple entries of an I/O request into backend's VA space. * The xbd_io->xio_gref array has to be filled out by the caller. */ static void * xbdback_map_shm(struct xbdback_io *xbd_io) { struct xbdback_instance *xbdi; struct xbdback_request *xbd_rq; int error, s; #ifdef XENDEBUG_VBD int i; printf("xbdback_map_shm map grant "); for (i = 0; i < xbd_io->xio_nrma; i++) { printf("%u ", (u_int)xbd_io->xio_gref[i]); } #endif KASSERT(xbd_io->xio_mapped == 0); xbdi = xbd_io->xio_xbdi; xbd_rq = SLIST_FIRST(&xbd_io->xio_rq)->car; error = xen_shm_map(xbd_io->xio_nrma, xbdi->xbdi_domid, xbd_io->xio_gref, &xbd_io->xio_vaddr, xbd_io->xio_gh, (xbd_rq->rq_operation == BLKIF_OP_WRITE) ? XSHM_RO : 0); switch(error) { case 0: #ifdef XENDEBUG_VBD printf("handle "); for (i = 0; i < xbd_io->xio_nrma; i++) { printf("%u ", (u_int)xbd_io->xio_gh[i]); } printf("\n"); #endif xbd_io->xio_mapped = 1; return xbdi; case ENOMEM: s = splvm(); if (!xbdback_shmcb) { if (xen_shm_callback(xbdback_shm_callback, xbdi) != 0) { splx(s); panic("xbdback_map_shm: " "xen_shm_callback failed"); } xbdback_shmcb = 1; } SIMPLEQ_INSERT_TAIL(&xbdback_shmq, xbdi, xbdi_on_hold); splx(s); /* Put the thread to sleep until the callback is called */ xbdi->xbdi_cont = xbdback_co_wait_shm_callback; return NULL; default: if (ratecheck(&xbdi->xbdi_lasterr_time, &xbdback_err_intvl)) { printf("xbdback_map_shm: xen_shm error %d ", error); } xbdback_io_error(xbdi->xbdi_io, error); xbdi->xbdi_io = NULL; xbdi->xbdi_cont = xbdi->xbdi_cont_aux; return xbdi; } } static int xbdback_shm_callback(void *arg) { int error, s; /* * The shm callback may be executed at any level, including * IPL_BIO and IPL_NET levels. Raise to the lowest priority level * that can mask both. */ s = splvm(); while(!SIMPLEQ_EMPTY(&xbdback_shmq)) { struct xbdback_instance *xbdi; struct xbdback_io *xbd_io; struct xbdback_request *xbd_rq; xbdi = SIMPLEQ_FIRST(&xbdback_shmq); xbd_io = xbdi->xbdi_io; xbd_rq = SLIST_FIRST(&xbd_io->xio_rq)->car; KASSERT(xbd_io->xio_mapped == 0); error = xen_shm_map(xbd_io->xio_nrma, xbdi->xbdi_domid, xbd_io->xio_gref, &xbd_io->xio_vaddr, xbd_io->xio_gh, XSHM_CALLBACK | ((xbd_rq->rq_operation == BLKIF_OP_WRITE) ? XSHM_RO: 0)); switch(error) { case ENOMEM: splx(s); return -1; /* will try again later */ case 0: SIMPLEQ_REMOVE_HEAD(&xbdback_shmq, xbdi_on_hold); xbd_io->xio_mapped = 1; xbdback_wakeup_thread(xbdi); break; default: SIMPLEQ_REMOVE_HEAD(&xbdback_shmq, xbdi_on_hold); printf("xbdback_shm_callback: xen_shm error %d\n", error); xbdback_io_error(xbd_io, error); xbdi->xbdi_io = NULL; xbdback_wakeup_thread(xbdi); break; } } xbdback_shmcb = 0; splx(s); return 0; } /* * Allows waiting for the shm callback to complete. */ static void * xbdback_co_wait_shm_callback(struct xbdback_instance *xbdi, void *obj) { if (xbdi->xbdi_io == NULL || xbdi->xbdi_io->xio_mapped == 1) { /* * Only proceed to next step when the callback reported * success or failure. */ xbdi->xbdi_cont = xbdi->xbdi_cont_aux; return xbdi; } else { /* go back to sleep */ return NULL; } } /* unmap a request from our virtual address space (request is done) */ static void xbdback_unmap_shm(struct xbdback_io *xbd_io) { #ifdef XENDEBUG_VBD int i; printf("xbdback_unmap_shm handle "); for (i = 0; i < xbd_io->xio_nrma; i++) { printf("%u ", (u_int)xbd_io->xio_gh[i]); } printf("\n"); #endif KASSERT(xbd_io->xio_mapped == 1); xbd_io->xio_mapped = 0; xen_shm_unmap(xbd_io->xio_vaddr, xbd_io->xio_nrma, xbd_io->xio_gh); xbd_io->xio_vaddr = -1; } /* Obtain memory from a pool */ static void * xbdback_pool_get(struct xbdback_pool *pp, struct xbdback_instance *xbdi) { return pool_cache_get(&pp->pc, PR_WAITOK); } /* Restore memory to a pool */ static void xbdback_pool_put(struct xbdback_pool *pp, void *item) { pool_cache_put(&pp->pc, item); } /* * Trampoline routine. Calls continuations in a loop and only exits when * either the returned object or the next callback is NULL. */ static void xbdback_trampoline(struct xbdback_instance *xbdi, void *obj) { xbdback_cont_t cont; while(obj != NULL && xbdi->xbdi_cont != NULL) { cont = xbdi->xbdi_cont; #ifdef DIAGNOSTIC xbdi->xbdi_cont = (xbdback_cont_t)0xDEADBEEF; #endif obj = (*cont)(xbdi, obj); #ifdef DIAGNOSTIC if (xbdi->xbdi_cont == (xbdback_cont_t)0xDEADBEEF) { printf("xbdback_trampoline: 0x%lx didn't set " "xbdi->xbdi_cont!\n", (long)cont); panic("xbdback_trampoline: bad continuation"); } #endif } }