/* * xen paravirt block device backend * * (c) Gerd Hoffmann * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; under version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, see . * * Contributions after 2012-01-13 are licensed under the terms of the * GNU GPL, version 2 or (at your option) any later version. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "hw/hw.h" #include "hw/xen/xen_backend.h" #include "xen_blkif.h" #include "sysemu/blockdev.h" #include "sysemu/block-backend.h" /* ------------------------------------------------------------- */ static int batch_maps = 0; static int max_requests = 32; /* ------------------------------------------------------------- */ #define BLOCK_SIZE 512 #define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2) struct PersistentGrant { void *page; struct XenBlkDev *blkdev; }; typedef struct PersistentGrant PersistentGrant; struct ioreq { blkif_request_t req; int16_t status; /* parsed request */ off_t start; QEMUIOVector v; int presync; int postsync; uint8_t mapped; /* grant mapping */ uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST]; uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST]; int prot; void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST]; void *pages; int num_unmap; /* aio status */ int aio_inflight; int aio_errors; struct XenBlkDev *blkdev; QLIST_ENTRY(ioreq) list; BlockAcctCookie acct; }; struct XenBlkDev { struct XenDevice xendev; /* must be first */ char *params; char *mode; char *type; char *dev; char *devtype; bool directiosafe; const char *fileproto; const char *filename; int ring_ref; void *sring; int64_t file_blk; int64_t file_size; int protocol; blkif_back_rings_t rings; int more_work; int cnt_map; /* request lists */ QLIST_HEAD(inflight_head, ioreq) inflight; QLIST_HEAD(finished_head, ioreq) finished; QLIST_HEAD(freelist_head, ioreq) freelist; int requests_total; int requests_inflight; int requests_finished; /* Persistent grants extension */ gboolean feature_discard; gboolean feature_persistent; GTree *persistent_gnts; unsigned int persistent_gnt_count; unsigned int max_grants; /* qemu block driver */ DriveInfo *dinfo; BlockDriverState *bs; QEMUBH *bh; }; /* ------------------------------------------------------------- */ static void ioreq_reset(struct ioreq *ioreq) { memset(&ioreq->req, 0, sizeof(ioreq->req)); ioreq->status = 0; ioreq->start = 0; ioreq->presync = 0; ioreq->postsync = 0; ioreq->mapped = 0; memset(ioreq->domids, 0, sizeof(ioreq->domids)); memset(ioreq->refs, 0, sizeof(ioreq->refs)); ioreq->prot = 0; memset(ioreq->page, 0, sizeof(ioreq->page)); ioreq->pages = NULL; ioreq->aio_inflight = 0; ioreq->aio_errors = 0; ioreq->blkdev = NULL; memset(&ioreq->list, 0, sizeof(ioreq->list)); memset(&ioreq->acct, 0, sizeof(ioreq->acct)); qemu_iovec_reset(&ioreq->v); } static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data) { uint ua = GPOINTER_TO_UINT(a); uint ub = GPOINTER_TO_UINT(b); return (ua > ub) - (ua < ub); } static void destroy_grant(gpointer pgnt) { PersistentGrant *grant = pgnt; XenGnttab gnt = grant->blkdev->xendev.gnttabdev; if (xc_gnttab_munmap(gnt, grant->page, 1) != 0) { xen_be_printf(&grant->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n", strerror(errno)); } grant->blkdev->persistent_gnt_count--; xen_be_printf(&grant->blkdev->xendev, 3, "unmapped grant %p\n", grant->page); g_free(grant); } static struct ioreq *ioreq_start(struct XenBlkDev *blkdev) { struct ioreq *ioreq = NULL; if (QLIST_EMPTY(&blkdev->freelist)) { if (blkdev->requests_total >= max_requests) { goto out; } /* allocate new struct */ ioreq = g_malloc0(sizeof(*ioreq)); ioreq->blkdev = blkdev; blkdev->requests_total++; qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST); } else { /* get one from freelist */ ioreq = QLIST_FIRST(&blkdev->freelist); QLIST_REMOVE(ioreq, list); } QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list); blkdev->requests_inflight++; out: return ioreq; } static void ioreq_finish(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; QLIST_REMOVE(ioreq, list); QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list); blkdev->requests_inflight--; blkdev->requests_finished++; } static void ioreq_release(struct ioreq *ioreq, bool finish) { struct XenBlkDev *blkdev = ioreq->blkdev; QLIST_REMOVE(ioreq, list); ioreq_reset(ioreq); ioreq->blkdev = blkdev; QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list); if (finish) { blkdev->requests_finished--; } else { blkdev->requests_inflight--; } } /* * translate request into iovec + start offset * do sanity checks along the way */ static int ioreq_parse(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; uintptr_t mem; size_t len; int i; xen_be_printf(&blkdev->xendev, 3, "op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n", ioreq->req.operation, ioreq->req.nr_segments, ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number); switch (ioreq->req.operation) { case BLKIF_OP_READ: ioreq->prot = PROT_WRITE; /* to memory */ break; case BLKIF_OP_FLUSH_DISKCACHE: ioreq->presync = 1; if (!ioreq->req.nr_segments) { return 0; } /* fall through */ case BLKIF_OP_WRITE: ioreq->prot = PROT_READ; /* from memory */ break; case BLKIF_OP_DISCARD: return 0; default: xen_be_printf(&blkdev->xendev, 0, "error: unknown operation (%d)\n", ioreq->req.operation); goto err; }; if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') { xen_be_printf(&blkdev->xendev, 0, "error: write req for ro device\n"); goto err; } ioreq->start = ioreq->req.sector_number * blkdev->file_blk; for (i = 0; i < ioreq->req.nr_segments; i++) { if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) { xen_be_printf(&blkdev->xendev, 0, "error: nr_segments too big\n"); goto err; } if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) { xen_be_printf(&blkdev->xendev, 0, "error: first > last sector\n"); goto err; } if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) { xen_be_printf(&blkdev->xendev, 0, "error: page crossing\n"); goto err; } ioreq->domids[i] = blkdev->xendev.dom; ioreq->refs[i] = ioreq->req.seg[i].gref; mem = ioreq->req.seg[i].first_sect * blkdev->file_blk; len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk; qemu_iovec_add(&ioreq->v, (void*)mem, len); } if (ioreq->start + ioreq->v.size > blkdev->file_size) { xen_be_printf(&blkdev->xendev, 0, "error: access beyond end of file\n"); goto err; } return 0; err: ioreq->status = BLKIF_RSP_ERROR; return -1; } static void ioreq_unmap(struct ioreq *ioreq) { XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev; int i; if (ioreq->num_unmap == 0 || ioreq->mapped == 0) { return; } if (batch_maps) { if (!ioreq->pages) { return; } if (xc_gnttab_munmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) { xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n", strerror(errno)); } ioreq->blkdev->cnt_map -= ioreq->num_unmap; ioreq->pages = NULL; } else { for (i = 0; i < ioreq->num_unmap; i++) { if (!ioreq->page[i]) { continue; } if (xc_gnttab_munmap(gnt, ioreq->page[i], 1) != 0) { xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n", strerror(errno)); } ioreq->blkdev->cnt_map--; ioreq->page[i] = NULL; } } ioreq->mapped = 0; } static int ioreq_map(struct ioreq *ioreq) { XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev; uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST]; uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST]; void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST]; int i, j, new_maps = 0; PersistentGrant *grant; /* domids and refs variables will contain the information necessary * to map the grants that are needed to fulfill this request. * * After mapping the needed grants, the page array will contain the * memory address of each granted page in the order specified in ioreq * (disregarding if it's a persistent grant or not). */ if (ioreq->v.niov == 0 || ioreq->mapped == 1) { return 0; } if (ioreq->blkdev->feature_persistent) { for (i = 0; i < ioreq->v.niov; i++) { grant = g_tree_lookup(ioreq->blkdev->persistent_gnts, GUINT_TO_POINTER(ioreq->refs[i])); if (grant != NULL) { page[i] = grant->page; xen_be_printf(&ioreq->blkdev->xendev, 3, "using persistent-grant %" PRIu32 "\n", ioreq->refs[i]); } else { /* Add the grant to the list of grants that * should be mapped */ domids[new_maps] = ioreq->domids[i]; refs[new_maps] = ioreq->refs[i]; page[i] = NULL; new_maps++; } } /* Set the protection to RW, since grants may be reused later * with a different protection than the one needed for this request */ ioreq->prot = PROT_WRITE | PROT_READ; } else { /* All grants in the request should be mapped */ memcpy(refs, ioreq->refs, sizeof(refs)); memcpy(domids, ioreq->domids, sizeof(domids)); memset(page, 0, sizeof(page)); new_maps = ioreq->v.niov; } if (batch_maps && new_maps) { ioreq->pages = xc_gnttab_map_grant_refs (gnt, new_maps, domids, refs, ioreq->prot); if (ioreq->pages == NULL) { xen_be_printf(&ioreq->blkdev->xendev, 0, "can't map %d grant refs (%s, %d maps)\n", new_maps, strerror(errno), ioreq->blkdev->cnt_map); return -1; } for (i = 0, j = 0; i < ioreq->v.niov; i++) { if (page[i] == NULL) { page[i] = ioreq->pages + (j++) * XC_PAGE_SIZE; } } ioreq->blkdev->cnt_map += new_maps; } else if (new_maps) { for (i = 0; i < new_maps; i++) { ioreq->page[i] = xc_gnttab_map_grant_ref (gnt, domids[i], refs[i], ioreq->prot); if (ioreq->page[i] == NULL) { xen_be_printf(&ioreq->blkdev->xendev, 0, "can't map grant ref %d (%s, %d maps)\n", refs[i], strerror(errno), ioreq->blkdev->cnt_map); ioreq->mapped = 1; ioreq_unmap(ioreq); return -1; } ioreq->blkdev->cnt_map++; } for (i = 0, j = 0; i < ioreq->v.niov; i++) { if (page[i] == NULL) { page[i] = ioreq->page[j++]; } } } if (ioreq->blkdev->feature_persistent) { while ((ioreq->blkdev->persistent_gnt_count < ioreq->blkdev->max_grants) && new_maps) { /* Go through the list of newly mapped grants and add as many * as possible to the list of persistently mapped grants. * * Since we start at the end of ioreq->page(s), we only need * to decrease new_maps to prevent this granted pages from * being unmapped in ioreq_unmap. */ grant = g_malloc0(sizeof(*grant)); new_maps--; if (batch_maps) { grant->page = ioreq->pages + (new_maps) * XC_PAGE_SIZE; } else { grant->page = ioreq->page[new_maps]; } grant->blkdev = ioreq->blkdev; xen_be_printf(&ioreq->blkdev->xendev, 3, "adding grant %" PRIu32 " page: %p\n", refs[new_maps], grant->page); g_tree_insert(ioreq->blkdev->persistent_gnts, GUINT_TO_POINTER(refs[new_maps]), grant); ioreq->blkdev->persistent_gnt_count++; } } for (i = 0; i < ioreq->v.niov; i++) { ioreq->v.iov[i].iov_base += (uintptr_t)page[i]; } ioreq->mapped = 1; ioreq->num_unmap = new_maps; return 0; } static int ioreq_runio_qemu_aio(struct ioreq *ioreq); static void qemu_aio_complete(void *opaque, int ret) { struct ioreq *ioreq = opaque; if (ret != 0) { xen_be_printf(&ioreq->blkdev->xendev, 0, "%s I/O error\n", ioreq->req.operation == BLKIF_OP_READ ? "read" : "write"); ioreq->aio_errors++; } ioreq->aio_inflight--; if (ioreq->presync) { ioreq->presync = 0; ioreq_runio_qemu_aio(ioreq); return; } if (ioreq->aio_inflight > 0) { return; } if (ioreq->postsync) { ioreq->postsync = 0; ioreq->aio_inflight++; bdrv_aio_flush(ioreq->blkdev->bs, qemu_aio_complete, ioreq); return; } ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY; ioreq_unmap(ioreq); ioreq_finish(ioreq); switch (ioreq->req.operation) { case BLKIF_OP_WRITE: case BLKIF_OP_FLUSH_DISKCACHE: if (!ioreq->req.nr_segments) { break; } case BLKIF_OP_READ: block_acct_done(bdrv_get_stats(ioreq->blkdev->bs), &ioreq->acct); break; case BLKIF_OP_DISCARD: default: break; } qemu_bh_schedule(ioreq->blkdev->bh); } static int ioreq_runio_qemu_aio(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; if (ioreq->req.nr_segments && ioreq_map(ioreq) == -1) { goto err_no_map; } ioreq->aio_inflight++; if (ioreq->presync) { bdrv_aio_flush(ioreq->blkdev->bs, qemu_aio_complete, ioreq); return 0; } switch (ioreq->req.operation) { case BLKIF_OP_READ: block_acct_start(bdrv_get_stats(blkdev->bs), &ioreq->acct, ioreq->v.size, BLOCK_ACCT_READ); ioreq->aio_inflight++; bdrv_aio_readv(blkdev->bs, ioreq->start / BLOCK_SIZE, &ioreq->v, ioreq->v.size / BLOCK_SIZE, qemu_aio_complete, ioreq); break; case BLKIF_OP_WRITE: case BLKIF_OP_FLUSH_DISKCACHE: if (!ioreq->req.nr_segments) { break; } block_acct_start(bdrv_get_stats(blkdev->bs), &ioreq->acct, ioreq->v.size, BLOCK_ACCT_WRITE); ioreq->aio_inflight++; bdrv_aio_writev(blkdev->bs, ioreq->start / BLOCK_SIZE, &ioreq->v, ioreq->v.size / BLOCK_SIZE, qemu_aio_complete, ioreq); break; case BLKIF_OP_DISCARD: { struct blkif_request_discard *discard_req = (void *)&ioreq->req; ioreq->aio_inflight++; bdrv_aio_discard(blkdev->bs, discard_req->sector_number, discard_req->nr_sectors, qemu_aio_complete, ioreq); break; } default: /* unknown operation (shouldn't happen -- parse catches this) */ goto err; } qemu_aio_complete(ioreq, 0); return 0; err: ioreq_unmap(ioreq); err_no_map: ioreq_finish(ioreq); ioreq->status = BLKIF_RSP_ERROR; return -1; } static int blk_send_response_one(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; int send_notify = 0; int have_requests = 0; blkif_response_t resp; void *dst; resp.id = ioreq->req.id; resp.operation = ioreq->req.operation; resp.status = ioreq->status; /* Place on the response ring for the relevant domain. */ switch (blkdev->protocol) { case BLKIF_PROTOCOL_NATIVE: dst = RING_GET_RESPONSE(&blkdev->rings.native, blkdev->rings.native.rsp_prod_pvt); break; case BLKIF_PROTOCOL_X86_32: dst = RING_GET_RESPONSE(&blkdev->rings.x86_32_part, blkdev->rings.x86_32_part.rsp_prod_pvt); break; case BLKIF_PROTOCOL_X86_64: dst = RING_GET_RESPONSE(&blkdev->rings.x86_64_part, blkdev->rings.x86_64_part.rsp_prod_pvt); break; default: dst = NULL; return 0; } memcpy(dst, &resp, sizeof(resp)); blkdev->rings.common.rsp_prod_pvt++; RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify); if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) { /* * Tail check for pending requests. Allows frontend to avoid * notifications if requests are already in flight (lower * overheads and promotes batching). */ RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests); } else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) { have_requests = 1; } if (have_requests) { blkdev->more_work++; } return send_notify; } /* walk finished list, send outstanding responses, free requests */ static void blk_send_response_all(struct XenBlkDev *blkdev) { struct ioreq *ioreq; int send_notify = 0; while (!QLIST_EMPTY(&blkdev->finished)) { ioreq = QLIST_FIRST(&blkdev->finished); send_notify += blk_send_response_one(ioreq); ioreq_release(ioreq, true); } if (send_notify) { xen_be_send_notify(&blkdev->xendev); } } static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq, RING_IDX rc) { switch (blkdev->protocol) { case BLKIF_PROTOCOL_NATIVE: memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc), sizeof(ioreq->req)); break; case BLKIF_PROTOCOL_X86_32: blkif_get_x86_32_req(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc)); break; case BLKIF_PROTOCOL_X86_64: blkif_get_x86_64_req(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc)); break; } return 0; } static void blk_handle_requests(struct XenBlkDev *blkdev) { RING_IDX rc, rp; struct ioreq *ioreq; blkdev->more_work = 0; rc = blkdev->rings.common.req_cons; rp = blkdev->rings.common.sring->req_prod; xen_rmb(); /* Ensure we see queued requests up to 'rp'. */ blk_send_response_all(blkdev); while (rc != rp) { /* pull request from ring */ if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc)) { break; } ioreq = ioreq_start(blkdev); if (ioreq == NULL) { blkdev->more_work++; break; } blk_get_request(blkdev, ioreq, rc); blkdev->rings.common.req_cons = ++rc; /* parse them */ if (ioreq_parse(ioreq) != 0) { if (blk_send_response_one(ioreq)) { xen_be_send_notify(&blkdev->xendev); } ioreq_release(ioreq, false); continue; } ioreq_runio_qemu_aio(ioreq); } if (blkdev->more_work && blkdev->requests_inflight < max_requests) { qemu_bh_schedule(blkdev->bh); } } /* ------------------------------------------------------------- */ static void blk_bh(void *opaque) { struct XenBlkDev *blkdev = opaque; blk_handle_requests(blkdev); } /* * We need to account for the grant allocations requiring contiguous * chunks; the worst case number would be * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, * but in order to keep things simple just use * 2 * max_req * max_seg. */ #define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) static void blk_alloc(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); QLIST_INIT(&blkdev->inflight); QLIST_INIT(&blkdev->finished); QLIST_INIT(&blkdev->freelist); blkdev->bh = qemu_bh_new(blk_bh, blkdev); if (xen_mode != XEN_EMULATE) { batch_maps = 1; } if (xc_gnttab_set_max_grants(xendev->gnttabdev, MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) { xen_be_printf(xendev, 0, "xc_gnttab_set_max_grants failed: %s\n", strerror(errno)); } } static void blk_parse_discard(struct XenBlkDev *blkdev) { int enable; blkdev->feature_discard = true; if (xenstore_read_be_int(&blkdev->xendev, "discard-enable", &enable) == 0) { blkdev->feature_discard = !!enable; } if (blkdev->feature_discard) { xenstore_write_be_int(&blkdev->xendev, "feature-discard", 1); } } static int blk_init(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); int info = 0; char *directiosafe = NULL; /* read xenstore entries */ if (blkdev->params == NULL) { char *h = NULL; blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params"); if (blkdev->params != NULL) { h = strchr(blkdev->params, ':'); } if (h != NULL) { blkdev->fileproto = blkdev->params; blkdev->filename = h+1; *h = 0; } else { blkdev->fileproto = ""; blkdev->filename = blkdev->params; } } if (!strcmp("aio", blkdev->fileproto)) { blkdev->fileproto = "raw"; } if (blkdev->mode == NULL) { blkdev->mode = xenstore_read_be_str(&blkdev->xendev, "mode"); } if (blkdev->type == NULL) { blkdev->type = xenstore_read_be_str(&blkdev->xendev, "type"); } if (blkdev->dev == NULL) { blkdev->dev = xenstore_read_be_str(&blkdev->xendev, "dev"); } if (blkdev->devtype == NULL) { blkdev->devtype = xenstore_read_be_str(&blkdev->xendev, "device-type"); } directiosafe = xenstore_read_be_str(&blkdev->xendev, "direct-io-safe"); blkdev->directiosafe = (directiosafe && atoi(directiosafe)); /* do we have all we need? */ if (blkdev->params == NULL || blkdev->mode == NULL || blkdev->type == NULL || blkdev->dev == NULL) { goto out_error; } /* read-only ? */ if (strcmp(blkdev->mode, "w")) { info |= VDISK_READONLY; } /* cdrom ? */ if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom")) { info |= VDISK_CDROM; } blkdev->file_blk = BLOCK_SIZE; /* fill info * blk_connect supplies sector-size and sectors */ xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1); xenstore_write_be_int(&blkdev->xendev, "feature-persistent", 1); xenstore_write_be_int(&blkdev->xendev, "info", info); blk_parse_discard(blkdev); g_free(directiosafe); return 0; out_error: g_free(blkdev->params); blkdev->params = NULL; g_free(blkdev->mode); blkdev->mode = NULL; g_free(blkdev->type); blkdev->type = NULL; g_free(blkdev->dev); blkdev->dev = NULL; g_free(blkdev->devtype); blkdev->devtype = NULL; g_free(directiosafe); blkdev->directiosafe = false; return -1; } static int blk_connect(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); int pers, index, qflags; bool readonly = true; /* read-only ? */ if (blkdev->directiosafe) { qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO; } else { qflags = BDRV_O_CACHE_WB; } if (strcmp(blkdev->mode, "w") == 0) { qflags |= BDRV_O_RDWR; readonly = false; } if (blkdev->feature_discard) { qflags |= BDRV_O_UNMAP; } /* init qemu block driver */ index = (blkdev->xendev.dev - 202 * 256) / 16; blkdev->dinfo = drive_get(IF_XEN, 0, index); if (!blkdev->dinfo) { Error *local_err = NULL; BlockBackend *blk; BlockDriver *drv; /* setup via xenbus -> create new block driver instance */ xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n"); blk = blk_new_with_bs(blkdev->dev, NULL); if (!blk) { return -1; } blkdev->bs = blk_bs(blk); drv = bdrv_find_whitelisted_format(blkdev->fileproto, readonly); if (bdrv_open(&blkdev->bs, blkdev->filename, NULL, NULL, qflags, drv, &local_err) != 0) { xen_be_printf(&blkdev->xendev, 0, "error: %s\n", error_get_pretty(local_err)); error_free(local_err); blk_unref(blk); blkdev->bs = NULL; return -1; } } else { /* setup via qemu cmdline -> already setup for us */ xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline setup)\n"); blkdev->bs = blkdev->dinfo->bdrv; if (bdrv_is_read_only(blkdev->bs) && !readonly) { xen_be_printf(&blkdev->xendev, 0, "Unexpected read-only drive"); blkdev->bs = NULL; return -1; } /* blkdev->bs is not create by us, we get a reference * so we can bdrv_unref() unconditionally */ /* Except we don't bdrv_unref() anymore, we blk_unref(). * Conditionally, because we can't easily blk_ref() here. * TODO Clean this up! */ } bdrv_attach_dev_nofail(blkdev->bs, blkdev); blkdev->file_size = bdrv_getlength(blkdev->bs); if (blkdev->file_size < 0) { xen_be_printf(&blkdev->xendev, 1, "bdrv_getlength: %d (%s) | drv %s\n", (int)blkdev->file_size, strerror(-blkdev->file_size), bdrv_get_format_name(blkdev->bs) ?: "-"); blkdev->file_size = 0; } xen_be_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\"," " size %" PRId64 " (%" PRId64 " MB)\n", blkdev->type, blkdev->fileproto, blkdev->filename, blkdev->file_size, blkdev->file_size >> 20); /* Fill in number of sector size and number of sectors */ xenstore_write_be_int(&blkdev->xendev, "sector-size", blkdev->file_blk); xenstore_write_be_int64(&blkdev->xendev, "sectors", blkdev->file_size / blkdev->file_blk); if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev->ring_ref) == -1) { return -1; } if (xenstore_read_fe_int(&blkdev->xendev, "event-channel", &blkdev->xendev.remote_port) == -1) { return -1; } if (xenstore_read_fe_int(&blkdev->xendev, "feature-persistent", &pers)) { blkdev->feature_persistent = FALSE; } else { blkdev->feature_persistent = !!pers; } blkdev->protocol = BLKIF_PROTOCOL_NATIVE; if (blkdev->xendev.protocol) { if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0) { blkdev->protocol = BLKIF_PROTOCOL_X86_32; } if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0) { blkdev->protocol = BLKIF_PROTOCOL_X86_64; } } blkdev->sring = xc_gnttab_map_grant_ref(blkdev->xendev.gnttabdev, blkdev->xendev.dom, blkdev->ring_ref, PROT_READ | PROT_WRITE); if (!blkdev->sring) { return -1; } blkdev->cnt_map++; switch (blkdev->protocol) { case BLKIF_PROTOCOL_NATIVE: { blkif_sring_t *sring_native = blkdev->sring; BACK_RING_INIT(&blkdev->rings.native, sring_native, XC_PAGE_SIZE); break; } case BLKIF_PROTOCOL_X86_32: { blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring; BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, XC_PAGE_SIZE); break; } case BLKIF_PROTOCOL_X86_64: { blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring; BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, XC_PAGE_SIZE); break; } } if (blkdev->feature_persistent) { /* Init persistent grants */ blkdev->max_grants = max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST; blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp, NULL, NULL, (GDestroyNotify)destroy_grant); blkdev->persistent_gnt_count = 0; } xen_be_bind_evtchn(&blkdev->xendev); xen_be_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, " "remote port %d, local port %d\n", blkdev->xendev.protocol, blkdev->ring_ref, blkdev->xendev.remote_port, blkdev->xendev.local_port); return 0; } static void blk_disconnect(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); if (blkdev->bs) { bdrv_detach_dev(blkdev->bs, blkdev); if (!blkdev->dinfo) { blk_unref(blk_by_name(blkdev->dev)); } blkdev->bs = NULL; } xen_be_unbind_evtchn(&blkdev->xendev); if (blkdev->sring) { xc_gnttab_munmap(blkdev->xendev.gnttabdev, blkdev->sring, 1); blkdev->cnt_map--; blkdev->sring = NULL; } } static int blk_free(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); struct ioreq *ioreq; if (blkdev->bs || blkdev->sring) { blk_disconnect(xendev); } /* Free persistent grants */ if (blkdev->feature_persistent) { g_tree_destroy(blkdev->persistent_gnts); } while (!QLIST_EMPTY(&blkdev->freelist)) { ioreq = QLIST_FIRST(&blkdev->freelist); QLIST_REMOVE(ioreq, list); qemu_iovec_destroy(&ioreq->v); g_free(ioreq); } g_free(blkdev->params); g_free(blkdev->mode); g_free(blkdev->type); g_free(blkdev->dev); g_free(blkdev->devtype); qemu_bh_delete(blkdev->bh); return 0; } static void blk_event(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); qemu_bh_schedule(blkdev->bh); } struct XenDevOps xen_blkdev_ops = { .size = sizeof(struct XenBlkDev), .flags = DEVOPS_FLAG_NEED_GNTDEV, .alloc = blk_alloc, .init = blk_init, .initialise = blk_connect, .disconnect = blk_disconnect, .event = blk_event, .free = blk_free, };