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gntdev.c
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Editing: gntdev.c
/*- * Copyright (c) 2016 Akshay Jaggi <jaggi@FreeBSD.org> * All rights reserved. * * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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. * * gntdev.c * * Interface to /dev/xen/gntdev. * */ #include <sys/cdefs.h> __FBSDID("$FreeBSD$"); #include <sys/param.h> #include <sys/systm.h> #include <sys/uio.h> #include <sys/bus.h> #include <sys/malloc.h> #include <sys/kernel.h> #include <sys/lock.h> #include <sys/mutex.h> #include <sys/rwlock.h> #include <sys/selinfo.h> #include <sys/poll.h> #include <sys/conf.h> #include <sys/fcntl.h> #include <sys/ioccom.h> #include <sys/rman.h> #include <sys/tree.h> #include <sys/module.h> #include <sys/proc.h> #include <sys/bitset.h> #include <sys/queue.h> #include <sys/mman.h> #include <sys/syslog.h> #include <sys/taskqueue.h> #include <vm/vm.h> #include <vm/vm_param.h> #include <vm/vm_extern.h> #include <vm/vm_kern.h> #include <vm/vm_page.h> #include <vm/vm_map.h> #include <vm/vm_object.h> #include <vm/vm_pager.h> #include <machine/md_var.h> #include <xen/xen-os.h> #include <xen/hypervisor.h> #include <xen/error.h> #include <xen/xen_intr.h> #include <xen/gnttab.h> #include <xen/gntdev.h> MALLOC_DEFINE(M_GNTDEV, "gntdev", "Xen grant-table user-space device"); #define MAX_OFFSET_COUNT ((0xffffffffffffffffull >> PAGE_SHIFT) + 1) static d_open_t gntdev_open; static d_ioctl_t gntdev_ioctl; static d_mmap_single_t gntdev_mmap_single; static struct cdevsw gntdev_devsw = { .d_version = D_VERSION, .d_open = gntdev_open, .d_ioctl = gntdev_ioctl, .d_mmap_single = gntdev_mmap_single, .d_name = "gntdev", }; static device_t gntdev_dev = NULL; struct gntdev_gref; struct gntdev_gmap; STAILQ_HEAD(gref_list_head, gntdev_gref); STAILQ_HEAD(gmap_list_head, gntdev_gmap); RB_HEAD(gref_tree_head, gntdev_gref); RB_HEAD(gmap_tree_head, gntdev_gmap); struct file_offset_struct { RB_ENTRY(file_offset_struct) next; uint64_t file_offset; uint64_t count; }; static int offset_cmp(struct file_offset_struct *f1, struct file_offset_struct *f2) { return (f1->file_offset - f2->file_offset); } RB_HEAD(file_offset_head, file_offset_struct); RB_GENERATE_STATIC(file_offset_head, file_offset_struct, next, offset_cmp); struct per_user_data { struct mtx user_data_lock; struct gref_tree_head gref_tree; struct gmap_tree_head gmap_tree; struct file_offset_head file_offset; }; /* * Get offset into the file which will be used while mmapping the * appropriate pages by the userspace program. */ static int get_file_offset(struct per_user_data *priv_user, uint32_t count, uint64_t *file_offset) { struct file_offset_struct *offset, *offset_tmp; if (count == 0) return (EINVAL); mtx_lock(&priv_user->user_data_lock); RB_FOREACH_SAFE(offset, file_offset_head, &priv_user->file_offset, offset_tmp) { if (offset->count >= count) { offset->count -= count; *file_offset = offset->file_offset + offset->count * PAGE_SIZE; if (offset->count == 0) { RB_REMOVE(file_offset_head, &priv_user->file_offset, offset); free(offset, M_GNTDEV); } mtx_unlock(&priv_user->user_data_lock); return (0); } } mtx_unlock(&priv_user->user_data_lock); return (ENOSPC); } static void put_file_offset(struct per_user_data *priv_user, uint32_t count, uint64_t file_offset) { struct file_offset_struct *offset, *offset_nxt, *offset_prv; offset = malloc(sizeof(*offset), M_GNTDEV, M_WAITOK | M_ZERO); offset->file_offset = file_offset; offset->count = count; mtx_lock(&priv_user->user_data_lock); RB_INSERT(file_offset_head, &priv_user->file_offset, offset); offset_nxt = RB_NEXT(file_offset_head, &priv_user->file_offset, offset); offset_prv = RB_PREV(file_offset_head, &priv_user->file_offset, offset); if (offset_nxt != NULL && offset_nxt->file_offset == offset->file_offset + offset->count * PAGE_SIZE) { offset->count += offset_nxt->count; RB_REMOVE(file_offset_head, &priv_user->file_offset, offset_nxt); free(offset_nxt, M_GNTDEV); } if (offset_prv != NULL && offset->file_offset == offset_prv->file_offset + offset_prv->count * PAGE_SIZE) { offset_prv->count += offset->count; RB_REMOVE(file_offset_head, &priv_user->file_offset, offset); free(offset, M_GNTDEV); } mtx_unlock(&priv_user->user_data_lock); } static int gntdev_gmap_pg_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred, u_short *color); static void gntdev_gmap_pg_dtor(void *handle); static int gntdev_gmap_pg_fault(vm_object_t object, vm_ooffset_t offset, int prot, vm_page_t *mres); static struct cdev_pager_ops gntdev_gmap_pg_ops = { .cdev_pg_fault = gntdev_gmap_pg_fault, .cdev_pg_ctor = gntdev_gmap_pg_ctor, .cdev_pg_dtor = gntdev_gmap_pg_dtor, }; struct cleanup_data_struct { struct mtx to_kill_grefs_mtx; struct mtx to_kill_gmaps_mtx; struct gref_list_head to_kill_grefs; struct gmap_list_head to_kill_gmaps; }; static struct cleanup_data_struct cleanup_data = { .to_kill_grefs = STAILQ_HEAD_INITIALIZER(cleanup_data.to_kill_grefs), .to_kill_gmaps = STAILQ_HEAD_INITIALIZER(cleanup_data.to_kill_gmaps), }; MTX_SYSINIT(to_kill_grefs_mtx, &cleanup_data.to_kill_grefs_mtx, "gntdev to_kill_grefs mutex", MTX_DEF); MTX_SYSINIT(to_kill_gmaps_mtx, &cleanup_data.to_kill_gmaps_mtx, "gntdev to_kill_gmaps mutex", MTX_DEF); static void cleanup_function(void *arg, __unused int pending); static struct task cleanup_task = TASK_INITIALIZER(0, cleanup_function, &cleanup_data); struct notify_data { uint64_t index; uint32_t action; uint32_t event_channel_port; xen_intr_handle_t notify_evtchn_handle; }; static void notify(struct notify_data *notify, vm_page_t page); /*-------------------- Grant Allocation Methods -----------------------------*/ struct gntdev_gref { union gref_next_union { STAILQ_ENTRY(gntdev_gref) list; RB_ENTRY(gntdev_gref) tree; } gref_next; uint64_t file_index; grant_ref_t gref_id; vm_page_t page; struct notify_data *notify; }; static int gref_cmp(struct gntdev_gref *g1, struct gntdev_gref *g2) { return (g1->file_index - g2->file_index); } RB_GENERATE_STATIC(gref_tree_head, gntdev_gref, gref_next.tree, gref_cmp); /* * Traverse over the device-list of to-be-deleted grants allocated, and * if all accesses, both local mmaps and foreign maps, to them have ended, * destroy them. */ static void gref_list_dtor(struct cleanup_data_struct *cleanup_data) { struct gref_list_head tmp_grefs; struct gntdev_gref *gref, *gref_tmp, *gref_previous; STAILQ_INIT(&tmp_grefs); mtx_lock(&cleanup_data->to_kill_grefs_mtx); STAILQ_SWAP(&cleanup_data->to_kill_grefs, &tmp_grefs, gntdev_gref); mtx_unlock(&cleanup_data->to_kill_grefs_mtx); gref_previous = NULL; STAILQ_FOREACH_SAFE(gref, &tmp_grefs, gref_next.list, gref_tmp) { if (gref->page && gref->page->object == NULL) { if (gref->notify) { notify(gref->notify, gref->page); } if (gref->gref_id != GRANT_REF_INVALID) { if (gnttab_query_foreign_access(gref->gref_id)) continue; if (gnttab_end_foreign_access_ref(gref->gref_id) == 0) continue; gnttab_free_grant_reference(gref->gref_id); } vm_page_unwire_noq(gref->page); vm_page_free(gref->page); gref->page = NULL; } if (gref->page == NULL) { if (gref_previous == NULL) STAILQ_REMOVE_HEAD(&tmp_grefs, gref_next.list); else STAILQ_REMOVE_AFTER(&tmp_grefs, gref_previous, gref_next.list); if (gref->notify) free(gref->notify, M_GNTDEV); free(gref, M_GNTDEV); } else gref_previous = gref; } if (!STAILQ_EMPTY(&tmp_grefs)) { mtx_lock(&cleanup_data->to_kill_grefs_mtx); STAILQ_CONCAT(&cleanup_data->to_kill_grefs, &tmp_grefs); mtx_unlock(&cleanup_data->to_kill_grefs_mtx); } } /* * Find count number of contiguous allocated grants for a given userspace * program by file-offset (index). */ static struct gntdev_gref* gntdev_find_grefs(struct per_user_data *priv_user, uint64_t index, uint32_t count) { struct gntdev_gref find_gref, *gref, *gref_start = NULL; find_gref.file_index = index; mtx_lock(&priv_user->user_data_lock); gref_start = RB_FIND(gref_tree_head, &priv_user->gref_tree, &find_gref); for (gref = gref_start; gref != NULL && count > 0; gref = RB_NEXT(gref_tree_head, &priv_user->gref_tree, gref)) { if (index != gref->file_index) break; index += PAGE_SIZE; count--; } mtx_unlock(&priv_user->user_data_lock); if (count) return (NULL); return (gref_start); } /* * IOCTL_GNTDEV_ALLOC_GREF * Allocate required number of wired pages for the request, grant foreign * access to the physical frames for these pages, and add details about * this allocation to the per user private data, so that these pages can * be mmapped by the userspace program. */ static int gntdev_alloc_gref(struct ioctl_gntdev_alloc_gref *arg) { uint32_t i; int error, readonly; uint64_t file_offset; struct gntdev_gref *grefs; struct per_user_data *priv_user; readonly = !(arg->flags & GNTDEV_ALLOC_FLAG_WRITABLE); error = devfs_get_cdevpriv((void**) &priv_user); if (error != 0) return (EINVAL); /* Cleanup grefs and free pages. */ taskqueue_enqueue(taskqueue_thread, &cleanup_task); /* Get file offset for this request. */ error = get_file_offset(priv_user, arg->count, &file_offset); if (error != 0) return (error); /* Allocate grefs. */ grefs = malloc(sizeof(*grefs) * arg->count, M_GNTDEV, M_WAITOK); for (i = 0; i < arg->count; i++) { grefs[i].file_index = file_offset + i * PAGE_SIZE; grefs[i].gref_id = GRANT_REF_INVALID; grefs[i].notify = NULL; grefs[i].page = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO); if (grefs[i].page == NULL) { log(LOG_ERR, "Page allocation failed."); error = ENOMEM; break; } if ((grefs[i].page->flags & PG_ZERO) == 0) { /* * Zero the allocated page, as we don't want to * leak our memory to other domains. */ pmap_zero_page(grefs[i].page); } grefs[i].page->valid = VM_PAGE_BITS_ALL; error = gnttab_grant_foreign_access(arg->domid, (VM_PAGE_TO_PHYS(grefs[i].page) >> PAGE_SHIFT), readonly, &grefs[i].gref_id); if (error != 0) { log(LOG_ERR, "Grant Table Hypercall failed."); break; } } if (error != 0) { /* * If target domain maps the gref (by guessing the gref-id), * then we can't clean it up yet and we have to leave the * page in place so as to not leak our memory to that domain. * Add it to a global list to be cleaned up later. */ mtx_lock(&cleanup_data.to_kill_grefs_mtx); for (i = 0; i < arg->count; i++) STAILQ_INSERT_TAIL(&cleanup_data.to_kill_grefs, &grefs[i], gref_next.list); mtx_unlock(&cleanup_data.to_kill_grefs_mtx); taskqueue_enqueue(taskqueue_thread, &cleanup_task); return (error); } /* Copy the output values. */ arg->index = file_offset; for (i = 0; i < arg->count; i++) suword32(&arg->gref_ids[i], grefs[i].gref_id); /* Modify the per user private data. */ mtx_lock(&priv_user->user_data_lock); for (i = 0; i < arg->count; i++) RB_INSERT(gref_tree_head, &priv_user->gref_tree, &grefs[i]); mtx_unlock(&priv_user->user_data_lock); return (error); } /* * IOCTL_GNTDEV_DEALLOC_GREF * Remove grant allocation information from the per user private data, so * that it can't be mmapped anymore by the userspace program, and add it * to the to-be-deleted grants global device-list. */ static int gntdev_dealloc_gref(struct ioctl_gntdev_dealloc_gref *arg) { int error; uint32_t count; struct gntdev_gref *gref, *gref_tmp; struct per_user_data *priv_user; error = devfs_get_cdevpriv((void**) &priv_user); if (error != 0) return (EINVAL); gref = gntdev_find_grefs(priv_user, arg->index, arg->count); if (gref == NULL) { log(LOG_ERR, "Can't find requested grant-refs."); return (EINVAL); } /* Remove the grefs from user private data. */ count = arg->count; mtx_lock(&priv_user->user_data_lock); mtx_lock(&cleanup_data.to_kill_grefs_mtx); for (; gref != NULL && count > 0; gref = gref_tmp) { gref_tmp = RB_NEXT(gref_tree_head, &priv_user->gref_tree, gref); RB_REMOVE(gref_tree_head, &priv_user->gref_tree, gref); STAILQ_INSERT_TAIL(&cleanup_data.to_kill_grefs, gref, gref_next.list); count--; } mtx_unlock(&cleanup_data.to_kill_grefs_mtx); mtx_unlock(&priv_user->user_data_lock); taskqueue_enqueue(taskqueue_thread, &cleanup_task); put_file_offset(priv_user, arg->count, arg->index); return (0); } /*-------------------- Grant Mapping Methods --------------------------------*/ struct gntdev_gmap_map { vm_object_t mem; struct resource *pseudo_phys_res; int pseudo_phys_res_id; vm_paddr_t phys_base_addr; }; struct gntdev_gmap { union gmap_next_union { STAILQ_ENTRY(gntdev_gmap) list; RB_ENTRY(gntdev_gmap) tree; } gmap_next; uint64_t file_index; uint32_t count; struct gnttab_map_grant_ref *grant_map_ops; struct gntdev_gmap_map *map; struct notify_data *notify; }; static int gmap_cmp(struct gntdev_gmap *g1, struct gntdev_gmap *g2) { return (g1->file_index - g2->file_index); } RB_GENERATE_STATIC(gmap_tree_head, gntdev_gmap, gmap_next.tree, gmap_cmp); /* * Traverse over the device-list of to-be-deleted grant mappings, and if * the region is no longer mmapped by anyone, free the memory used to * store information about the mapping. */ static void gmap_list_dtor(struct cleanup_data_struct *cleanup_data) { struct gmap_list_head tmp_gmaps; struct gntdev_gmap *gmap, *gmap_tmp, *gmap_previous; STAILQ_INIT(&tmp_gmaps); mtx_lock(&cleanup_data->to_kill_gmaps_mtx); STAILQ_SWAP(&cleanup_data->to_kill_gmaps, &tmp_gmaps, gntdev_gmap); mtx_unlock(&cleanup_data->to_kill_gmaps_mtx); gmap_previous = NULL; STAILQ_FOREACH_SAFE(gmap, &tmp_gmaps, gmap_next.list, gmap_tmp) { if (gmap->map == NULL) { if (gmap_previous == NULL) STAILQ_REMOVE_HEAD(&tmp_gmaps, gmap_next.list); else STAILQ_REMOVE_AFTER(&tmp_gmaps, gmap_previous, gmap_next.list); if (gmap->notify) free(gmap->notify, M_GNTDEV); free(gmap->grant_map_ops, M_GNTDEV); free(gmap, M_GNTDEV); } else gmap_previous = gmap; } if (!STAILQ_EMPTY(&tmp_gmaps)) { mtx_lock(&cleanup_data->to_kill_gmaps_mtx); STAILQ_CONCAT(&cleanup_data->to_kill_gmaps, &tmp_gmaps); mtx_unlock(&cleanup_data->to_kill_gmaps_mtx); } } /* * Find mapped grants for a given userspace program, by file-offset (index) * and count, as supplied during the map-ioctl. */ static struct gntdev_gmap* gntdev_find_gmap(struct per_user_data *priv_user, uint64_t index, uint32_t count) { struct gntdev_gmap find_gmap, *gmap; find_gmap.file_index = index; mtx_lock(&priv_user->user_data_lock); gmap = RB_FIND(gmap_tree_head, &priv_user->gmap_tree, &find_gmap); mtx_unlock(&priv_user->user_data_lock); if (gmap != NULL && gmap->count == count) return (gmap); return (NULL); } /* * Remove the pages from the mgtdevice pager, call the unmap hypercall, * free the xenmem resource. This function is called during the * destruction of the mgtdevice pager, which happens when all mmaps to * it have been removed, and the unmap-ioctl has been performed. */ static int notify_unmap_cleanup(struct gntdev_gmap *gmap) { uint32_t i; int error, count; vm_page_t m; struct gnttab_unmap_grant_ref *unmap_ops; unmap_ops = malloc(sizeof(struct gnttab_unmap_grant_ref) * gmap->count, M_GNTDEV, M_WAITOK); /* Enumerate freeable maps. */ count = 0; for (i = 0; i < gmap->count; i++) { if (gmap->grant_map_ops[i].handle != -1) { unmap_ops[count].handle = gmap->grant_map_ops[i].handle; unmap_ops[count].host_addr = gmap->grant_map_ops[i].host_addr; unmap_ops[count].dev_bus_addr = 0; count++; } } /* Perform notification. */ if (count > 0 && gmap->notify) { vm_page_t page; uint64_t page_offset; page_offset = gmap->notify->index - gmap->file_index; page = PHYS_TO_VM_PAGE(gmap->map->phys_base_addr + page_offset); notify(gmap->notify, page); } /* Free the pages. */ VM_OBJECT_WLOCK(gmap->map->mem); retry: for (i = 0; i < gmap->count; i++) { m = vm_page_lookup(gmap->map->mem, i); if (m == NULL) continue; if (vm_page_busy_acquire(m, VM_ALLOC_WAITFAIL) == 0) goto retry; cdev_pager_free_page(gmap->map->mem, m); } VM_OBJECT_WUNLOCK(gmap->map->mem); /* Perform unmap hypercall. */ error = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count); for (i = 0; i < gmap->count; i++) { gmap->grant_map_ops[i].handle = -1; gmap->grant_map_ops[i].host_addr = 0; } if (gmap->map) { error = xenmem_free(gntdev_dev, gmap->map->pseudo_phys_res_id, gmap->map->pseudo_phys_res); KASSERT(error == 0, ("Unable to release memory resource: %d", error)); free(gmap->map, M_GNTDEV); gmap->map = NULL; } free(unmap_ops, M_GNTDEV); return (error); } /* * IOCTL_GNTDEV_MAP_GRANT_REF * Populate structures for mapping the grant reference in the per user * private data. Actual resource allocation and map hypercall is performed * during the mmap. */ static int gntdev_map_grant_ref(struct ioctl_gntdev_map_grant_ref *arg) { uint32_t i; int error; struct gntdev_gmap *gmap; struct per_user_data *priv_user; error = devfs_get_cdevpriv((void**) &priv_user); if (error != 0) return (EINVAL); gmap = malloc(sizeof(*gmap), M_GNTDEV, M_WAITOK | M_ZERO); gmap->count = arg->count; gmap->grant_map_ops = malloc(sizeof(struct gnttab_map_grant_ref) * arg->count, M_GNTDEV, M_WAITOK | M_ZERO); for (i = 0; i < arg->count; i++) { struct ioctl_gntdev_grant_ref ref; error = copyin(&arg->refs[i], &ref, sizeof(ref)); if (error != 0) { free(gmap->grant_map_ops, M_GNTDEV); free(gmap, M_GNTDEV); return (error); } gmap->grant_map_ops[i].dom = ref.domid; gmap->grant_map_ops[i].ref = ref.ref; gmap->grant_map_ops[i].handle = -1; gmap->grant_map_ops[i].flags = GNTMAP_host_map; } error = get_file_offset(priv_user, arg->count, &gmap->file_index); if (error != 0) { free(gmap->grant_map_ops, M_GNTDEV); free(gmap, M_GNTDEV); return (error); } mtx_lock(&priv_user->user_data_lock); RB_INSERT(gmap_tree_head, &priv_user->gmap_tree, gmap); mtx_unlock(&priv_user->user_data_lock); arg->index = gmap->file_index; return (error); } /* * IOCTL_GNTDEV_UNMAP_GRANT_REF * Remove the map information from the per user private data and add it * to the global device-list of mappings to be deleted. A reference to * the mgtdevice pager is also decreased, the reason for which is * explained in mmap_gmap(). */ static int gntdev_unmap_grant_ref(struct ioctl_gntdev_unmap_grant_ref *arg) { int error; struct gntdev_gmap *gmap; struct per_user_data *priv_user; error = devfs_get_cdevpriv((void**) &priv_user); if (error != 0) return (EINVAL); gmap = gntdev_find_gmap(priv_user, arg->index, arg->count); if (gmap == NULL) { log(LOG_ERR, "Can't find requested grant-map."); return (EINVAL); } mtx_lock(&priv_user->user_data_lock); mtx_lock(&cleanup_data.to_kill_gmaps_mtx); RB_REMOVE(gmap_tree_head, &priv_user->gmap_tree, gmap); STAILQ_INSERT_TAIL(&cleanup_data.to_kill_gmaps, gmap, gmap_next.list); mtx_unlock(&cleanup_data.to_kill_gmaps_mtx); mtx_unlock(&priv_user->user_data_lock); if (gmap->map) vm_object_deallocate(gmap->map->mem); taskqueue_enqueue(taskqueue_thread, &cleanup_task); put_file_offset(priv_user, arg->count, arg->index); return (0); } /* * IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR * Get file-offset and count for a given mapping, from the virtual address * where the mapping is mmapped. * Please note, this only works for grants mapped by this domain, and not * grants allocated. Count doesn't make much sense in reference to grants * allocated. Also, because this function is present in the linux gntdev * device, but not in the linux gntalloc one, most userspace code only use * it for mapped grants. */ static int gntdev_get_offset_for_vaddr(struct ioctl_gntdev_get_offset_for_vaddr *arg, struct thread *td) { int error; vm_map_t map; vm_map_entry_t entry; vm_object_t mem; vm_pindex_t pindex; vm_prot_t prot; boolean_t wired; struct gntdev_gmap *gmap; int rc; map = &td->td_proc->p_vmspace->vm_map; error = vm_map_lookup(&map, arg->vaddr, VM_PROT_NONE, &entry, &mem, &pindex, &prot, &wired); if (error != KERN_SUCCESS) return (EINVAL); if ((mem->type != OBJT_MGTDEVICE) || (mem->un_pager.devp.ops != &gntdev_gmap_pg_ops)) { rc = EINVAL; goto out; } gmap = mem->handle; if (gmap == NULL || (entry->end - entry->start) != (gmap->count * PAGE_SIZE)) { rc = EINVAL; goto out; } arg->count = gmap->count; arg->offset = gmap->file_index; rc = 0; out: vm_map_lookup_done(map, entry); return (rc); } /*-------------------- Grant Mapping Pager ----------------------------------*/ static int gntdev_gmap_pg_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred, u_short *color) { return (0); } static void gntdev_gmap_pg_dtor(void *handle) { notify_unmap_cleanup((struct gntdev_gmap *)handle); } static int gntdev_gmap_pg_fault(vm_object_t object, vm_ooffset_t offset, int prot, vm_page_t *mres) { struct gntdev_gmap *gmap = object->handle; vm_pindex_t pidx, ridx; vm_page_t page; vm_ooffset_t relative_offset; if (gmap->map == NULL) return (VM_PAGER_FAIL); relative_offset = offset - gmap->file_index; pidx = OFF_TO_IDX(offset); ridx = OFF_TO_IDX(relative_offset); if (ridx >= gmap->count || gmap->grant_map_ops[ridx].status != GNTST_okay) return (VM_PAGER_FAIL); page = PHYS_TO_VM_PAGE(gmap->map->phys_base_addr + relative_offset); if (page == NULL) return (VM_PAGER_FAIL); KASSERT((page->flags & PG_FICTITIOUS) != 0, ("not fictitious %p", page)); KASSERT(vm_page_wired(page), ("page %p is not wired", page)); KASSERT(!vm_page_busied(page), ("page %p is busy", page)); vm_page_busy_acquire(page, 0); vm_page_valid(page); if (*mres != NULL) vm_page_replace(page, object, pidx, *mres); else vm_page_insert(page, object, pidx); *mres = page; return (VM_PAGER_OK); } /*------------------ Grant Table Methods ------------------------------------*/ static void notify(struct notify_data *notify, vm_page_t page) { if (notify->action & UNMAP_NOTIFY_CLEAR_BYTE) { uint8_t *mem; uint64_t offset; offset = notify->index & PAGE_MASK; mem = (uint8_t *)pmap_quick_enter_page(page); mem[offset] = 0; pmap_quick_remove_page((vm_offset_t)mem); } if (notify->action & UNMAP_NOTIFY_SEND_EVENT) { xen_intr_signal(notify->notify_evtchn_handle); xen_intr_unbind(¬ify->notify_evtchn_handle); } notify->action = 0; } /* * Helper to copy new arguments from the notify ioctl into * the existing notify data. */ static int copy_notify_helper(struct notify_data *destination, struct ioctl_gntdev_unmap_notify *source) { xen_intr_handle_t handlep = NULL; /* * "Get" before "Put"ting previous reference, as we might be * holding the last reference to the event channel port. */ if (source->action & UNMAP_NOTIFY_SEND_EVENT) if (xen_intr_get_evtchn_from_port(source->event_channel_port, &handlep) != 0) return (EINVAL); if (destination->action & UNMAP_NOTIFY_SEND_EVENT) xen_intr_unbind(&destination->notify_evtchn_handle); destination->action = source->action; destination->event_channel_port = source->event_channel_port; destination->index = source->index; destination->notify_evtchn_handle = handlep; return (0); } /* * IOCTL_GNTDEV_SET_UNMAP_NOTIFY * Set unmap notification inside the appropriate grant. It sends a * notification when the grant is completely munmapped by this domain * and ready for destruction. */ static int gntdev_set_unmap_notify(struct ioctl_gntdev_unmap_notify *arg) { int error; uint64_t index; struct per_user_data *priv_user; struct gntdev_gref *gref = NULL; struct gntdev_gmap *gmap; error = devfs_get_cdevpriv((void**) &priv_user); if (error != 0) return (EINVAL); if (arg->action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) return (EINVAL); index = arg->index & ~PAGE_MASK; gref = gntdev_find_grefs(priv_user, index, 1); if (gref) { if (gref->notify == NULL) gref->notify = malloc(sizeof(*arg), M_GNTDEV, M_WAITOK | M_ZERO); return (copy_notify_helper(gref->notify, arg)); } error = EINVAL; mtx_lock(&priv_user->user_data_lock); RB_FOREACH(gmap, gmap_tree_head, &priv_user->gmap_tree) { if (arg->index >= gmap->file_index && arg->index < gmap->file_index + gmap->count * PAGE_SIZE) { if (gmap->notify == NULL) gmap->notify = malloc(sizeof(*arg), M_GNTDEV, M_WAITOK | M_ZERO); error = copy_notify_helper(gmap->notify, arg); break; } } mtx_unlock(&priv_user->user_data_lock); return (error); } /*------------------ Gntdev Char Device Methods -----------------------------*/ static void cleanup_function(void *arg, __unused int pending) { gref_list_dtor((struct cleanup_data_struct *) arg); gmap_list_dtor((struct cleanup_data_struct *) arg); } static void per_user_data_dtor(void *arg) { struct gntdev_gref *gref, *gref_tmp; struct gntdev_gmap *gmap, *gmap_tmp; struct file_offset_struct *offset, *offset_tmp; struct per_user_data *priv_user; priv_user = (struct per_user_data *) arg; mtx_lock(&priv_user->user_data_lock); mtx_lock(&cleanup_data.to_kill_grefs_mtx); RB_FOREACH_SAFE(gref, gref_tree_head, &priv_user->gref_tree, gref_tmp) { RB_REMOVE(gref_tree_head, &priv_user->gref_tree, gref); STAILQ_INSERT_TAIL(&cleanup_data.to_kill_grefs, gref, gref_next.list); } mtx_unlock(&cleanup_data.to_kill_grefs_mtx); mtx_lock(&cleanup_data.to_kill_gmaps_mtx); RB_FOREACH_SAFE(gmap, gmap_tree_head, &priv_user->gmap_tree, gmap_tmp) { RB_REMOVE(gmap_tree_head, &priv_user->gmap_tree, gmap); STAILQ_INSERT_TAIL(&cleanup_data.to_kill_gmaps, gmap, gmap_next.list); if (gmap->map) vm_object_deallocate(gmap->map->mem); } mtx_unlock(&cleanup_data.to_kill_gmaps_mtx); RB_FOREACH_SAFE(offset, file_offset_head, &priv_user->file_offset, offset_tmp) { RB_REMOVE(file_offset_head, &priv_user->file_offset, offset); free(offset, M_GNTDEV); } mtx_unlock(&priv_user->user_data_lock); taskqueue_enqueue(taskqueue_thread, &cleanup_task); mtx_destroy(&priv_user->user_data_lock); free(priv_user, M_GNTDEV); } static int gntdev_open(struct cdev *dev, int flag, int otyp, struct thread *td) { int error; struct per_user_data *priv_user; struct file_offset_struct *offset; priv_user = malloc(sizeof(*priv_user), M_GNTDEV, M_WAITOK | M_ZERO); RB_INIT(&priv_user->gref_tree); RB_INIT(&priv_user->gmap_tree); RB_INIT(&priv_user->file_offset); offset = malloc(sizeof(*offset), M_GNTDEV, M_WAITOK | M_ZERO); offset->file_offset = 0; offset->count = MAX_OFFSET_COUNT; RB_INSERT(file_offset_head, &priv_user->file_offset, offset); mtx_init(&priv_user->user_data_lock, "per user data mutex", NULL, MTX_DEF); error = devfs_set_cdevpriv(priv_user, per_user_data_dtor); if (error != 0) per_user_data_dtor(priv_user); return (error); } static int gntdev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td) { int error; switch (cmd) { case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: error = gntdev_set_unmap_notify( (struct ioctl_gntdev_unmap_notify*) data); break; case IOCTL_GNTDEV_ALLOC_GREF: error = gntdev_alloc_gref( (struct ioctl_gntdev_alloc_gref*) data); break; case IOCTL_GNTDEV_DEALLOC_GREF: error = gntdev_dealloc_gref( (struct ioctl_gntdev_dealloc_gref*) data); break; case IOCTL_GNTDEV_MAP_GRANT_REF: error = gntdev_map_grant_ref( (struct ioctl_gntdev_map_grant_ref*) data); break; case IOCTL_GNTDEV_UNMAP_GRANT_REF: error = gntdev_unmap_grant_ref( (struct ioctl_gntdev_unmap_grant_ref*) data); break; case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: error = gntdev_get_offset_for_vaddr( (struct ioctl_gntdev_get_offset_for_vaddr*) data, td); break; default: error = ENOSYS; break; } return (error); } /* * MMAP an allocated grant into user memory. * Please note, that the grants must not already be mmapped, otherwise * this function will fail. */ static int mmap_gref(struct per_user_data *priv_user, struct gntdev_gref *gref_start, uint32_t count, vm_size_t size, struct vm_object **object) { vm_object_t mem_obj; struct gntdev_gref *gref; mem_obj = vm_pager_allocate(OBJT_PHYS, NULL, size, VM_PROT_ALL, 0, curthread->td_ucred); if (mem_obj == NULL) return (ENOMEM); mtx_lock(&priv_user->user_data_lock); VM_OBJECT_WLOCK(mem_obj); for (gref = gref_start; gref != NULL && count > 0; gref = RB_NEXT(gref_tree_head, &priv_user->gref_tree, gref)) { if (gref->page->object) break; vm_page_insert(gref->page, mem_obj, OFF_TO_IDX(gref->file_index)); count--; } VM_OBJECT_WUNLOCK(mem_obj); mtx_unlock(&priv_user->user_data_lock); if (count) { vm_object_deallocate(mem_obj); return (EINVAL); } *object = mem_obj; return (0); } /* * MMAP a mapped grant into user memory. */ static int mmap_gmap(struct per_user_data *priv_user, struct gntdev_gmap *gmap_start, vm_ooffset_t *offset, vm_size_t size, struct vm_object **object, int nprot) { uint32_t i; int error; /* * The grant map hypercall might already be done. * If that is the case, increase a reference to the * vm object and return the already allocated object. */ if (gmap_start->map) { vm_object_reference(gmap_start->map->mem); *object = gmap_start->map->mem; return (0); } gmap_start->map = malloc(sizeof(*(gmap_start->map)), M_GNTDEV, M_WAITOK | M_ZERO); /* Allocate the xen pseudo physical memory resource. */ gmap_start->map->pseudo_phys_res_id = 0; gmap_start->map->pseudo_phys_res = xenmem_alloc(gntdev_dev, &gmap_start->map->pseudo_phys_res_id, size); if (gmap_start->map->pseudo_phys_res == NULL) { free(gmap_start->map, M_GNTDEV); gmap_start->map = NULL; return (ENOMEM); } gmap_start->map->phys_base_addr = rman_get_start(gmap_start->map->pseudo_phys_res); /* Allocate the mgtdevice pager. */ gmap_start->map->mem = cdev_pager_allocate(gmap_start, OBJT_MGTDEVICE, &gntdev_gmap_pg_ops, size, nprot, *offset, NULL); if (gmap_start->map->mem == NULL) { xenmem_free(gntdev_dev, gmap_start->map->pseudo_phys_res_id, gmap_start->map->pseudo_phys_res); free(gmap_start->map, M_GNTDEV); gmap_start->map = NULL; return (ENOMEM); } for (i = 0; i < gmap_start->count; i++) { gmap_start->grant_map_ops[i].host_addr = gmap_start->map->phys_base_addr + i * PAGE_SIZE; if ((nprot & PROT_WRITE) == 0) gmap_start->grant_map_ops[i].flags |= GNTMAP_readonly; } /* Make the MAP hypercall. */ error = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, gmap_start->grant_map_ops, gmap_start->count); if (error != 0) { /* * Deallocate pager. * Pager deallocation will automatically take care of * xenmem deallocation, etc. */ vm_object_deallocate(gmap_start->map->mem); return (EINVAL); } /* Retry EAGAIN maps. */ for (i = 0; i < gmap_start->count; i++) { int delay = 1; while (delay < 256 && gmap_start->grant_map_ops[i].status == GNTST_eagain) { HYPERVISOR_grant_table_op( GNTTABOP_map_grant_ref, &gmap_start->grant_map_ops[i], 1); pause(("gntmap"), delay * SBT_1MS); delay++; } if (gmap_start->grant_map_ops[i].status == GNTST_eagain) gmap_start->grant_map_ops[i].status = GNTST_bad_page; if (gmap_start->grant_map_ops[i].status != GNTST_okay) { /* * Deallocate pager. * Pager deallocation will automatically take care of * xenmem deallocation, notification, unmap hypercall, * etc. */ vm_object_deallocate(gmap_start->map->mem); return (EINVAL); } } /* * Add a reference to the vm object. We do not want * the vm object to be deleted when all the mmaps are * unmapped, because it may be re-mmapped. Instead, * we want the object to be deleted, when along with * munmaps, we have also processed the unmap-ioctl. */ vm_object_reference(gmap_start->map->mem); *object = gmap_start->map->mem; return (0); } static int gntdev_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size, struct vm_object **object, int nprot) { int error; uint32_t count; struct gntdev_gref *gref_start; struct gntdev_gmap *gmap_start; struct per_user_data *priv_user; error = devfs_get_cdevpriv((void**) &priv_user); if (error != 0) return (EINVAL); count = OFF_TO_IDX(size); gref_start = gntdev_find_grefs(priv_user, *offset, count); if (gref_start) { error = mmap_gref(priv_user, gref_start, count, size, object); return (error); } gmap_start = gntdev_find_gmap(priv_user, *offset, count); if (gmap_start) { error = mmap_gmap(priv_user, gmap_start, offset, size, object, nprot); return (error); } return (EINVAL); } /*------------------ Private Device Attachment Functions --------------------*/ static void gntdev_identify(driver_t *driver, device_t parent) { KASSERT((xen_domain()), ("Trying to attach gntdev device on non Xen domain")); if (BUS_ADD_CHILD(parent, 0, "gntdev", 0) == NULL) panic("unable to attach gntdev user-space device"); } static int gntdev_probe(device_t dev) { gntdev_dev = dev; device_set_desc(dev, "Xen grant-table user-space device"); return (BUS_PROBE_NOWILDCARD); } static int gntdev_attach(device_t dev) { make_dev_credf(MAKEDEV_ETERNAL, &gntdev_devsw, 0, NULL, UID_ROOT, GID_WHEEL, 0600, "xen/gntdev"); return (0); } /*-------------------- Private Device Attachment Data -----------------------*/ static device_method_t gntdev_methods[] = { DEVMETHOD(device_identify, gntdev_identify), DEVMETHOD(device_probe, gntdev_probe), DEVMETHOD(device_attach, gntdev_attach), DEVMETHOD_END }; static driver_t gntdev_driver = { "gntdev", gntdev_methods, 0, }; devclass_t gntdev_devclass; DRIVER_MODULE(gntdev, xenpv, gntdev_driver, gntdev_devclass, 0, 0); MODULE_DEPEND(gntdev, xenpv, 1, 1, 1);
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