| /* |
| * xen paravirt block device backend |
| * |
| * (c) Gerd Hoffmann <kraxel@redhat.com> |
| * |
| * 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 <http://www.gnu.org/licenses/>. |
| * |
| * Contributions after 2012-01-13 are licensed under the terms of the |
| * GNU GPL, version 2 or (at your option) any later version. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include <sys/ioctl.h> |
| #include <sys/uio.h> |
| |
| #include "hw/hw.h" |
| #include "hw/xen/xen_backend.h" |
| #include "xen_blkif.h" |
| #include "sysemu/blockdev.h" |
| #include "sysemu/block-backend.h" |
| #include "qapi/error.h" |
| #include "qapi/qmp/qdict.h" |
| #include "qapi/qmp/qstring.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 PersistentRegion { |
| void *addr; |
| int num; |
| }; |
| |
| typedef struct PersistentRegion PersistentRegion; |
| |
| struct ioreq { |
| blkif_request_t req; |
| int16_t status; |
| |
| /* parsed request */ |
| off_t start; |
| QEMUIOVector v; |
| int presync; |
| 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; |
| GSList *persistent_regions; |
| unsigned int persistent_gnt_count; |
| unsigned int max_grants; |
| |
| /* qemu block driver */ |
| DriveInfo *dinfo; |
| BlockBackend *blk; |
| 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->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_handle *gnt = grant->blkdev->xendev.gnttabdev; |
| |
| if (xengnttab_unmap(gnt, grant->page, 1) != 0) { |
| xen_be_printf(&grant->blkdev->xendev, 0, |
| "xengnttab_unmap 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 void remove_persistent_region(gpointer data, gpointer dev) |
| { |
| PersistentRegion *region = data; |
| struct XenBlkDev *blkdev = dev; |
| xengnttab_handle *gnt = blkdev->xendev.gnttabdev; |
| |
| if (xengnttab_unmap(gnt, region->addr, region->num) != 0) { |
| xen_be_printf(&blkdev->xendev, 0, |
| "xengnttab_unmap region %p failed: %s\n", |
| region->addr, strerror(errno)); |
| } |
| xen_be_printf(&blkdev->xendev, 3, |
| "unmapped grant region %p with %d pages\n", |
| region->addr, region->num); |
| g_free(region); |
| } |
| |
| 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_handle *gnt = ioreq->blkdev->xendev.gnttabdev; |
| int i; |
| |
| if (ioreq->num_unmap == 0 || ioreq->mapped == 0) { |
| return; |
| } |
| if (batch_maps) { |
| if (!ioreq->pages) { |
| return; |
| } |
| if (xengnttab_unmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) { |
| xen_be_printf(&ioreq->blkdev->xendev, 0, |
| "xengnttab_unmap 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 (xengnttab_unmap(gnt, ioreq->page[i], 1) != 0) { |
| xen_be_printf(&ioreq->blkdev->xendev, 0, |
| "xengnttab_unmap failed: %s\n", |
| strerror(errno)); |
| } |
| ioreq->blkdev->cnt_map--; |
| ioreq->page[i] = NULL; |
| } |
| } |
| ioreq->mapped = 0; |
| } |
| |
| static int ioreq_map(struct ioreq *ioreq) |
| { |
| xengnttab_handle *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; |
| PersistentRegion *region; |
| /* 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 = xengnttab_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] = xengnttab_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 && new_maps != 0 && |
| (!batch_maps || (ioreq->blkdev->persistent_gnt_count + new_maps <= |
| ioreq->blkdev->max_grants))) { |
| /* |
| * If we are using persistent grants and batch mappings only |
| * add the new maps to the list of persistent grants if the whole |
| * area can be persistently mapped. |
| */ |
| if (batch_maps) { |
| region = g_malloc0(sizeof(*region)); |
| region->addr = ioreq->pages; |
| region->num = new_maps; |
| ioreq->blkdev->persistent_regions = g_slist_append( |
| ioreq->blkdev->persistent_regions, |
| region); |
| } |
| 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++; |
| } |
| assert(!batch_maps || new_maps == 0); |
| } |
| 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; |
| } |
| |
| 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: |
| if (ioreq->status == BLKIF_RSP_OKAY) { |
| block_acct_done(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct); |
| } else { |
| block_acct_failed(blk_get_stats(ioreq->blkdev->blk), &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) { |
| blk_aio_flush(ioreq->blkdev->blk, qemu_aio_complete, ioreq); |
| return 0; |
| } |
| |
| switch (ioreq->req.operation) { |
| case BLKIF_OP_READ: |
| block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct, |
| ioreq->v.size, BLOCK_ACCT_READ); |
| ioreq->aio_inflight++; |
| blk_aio_preadv(blkdev->blk, ioreq->start, &ioreq->v, 0, |
| qemu_aio_complete, ioreq); |
| break; |
| case BLKIF_OP_WRITE: |
| case BLKIF_OP_FLUSH_DISKCACHE: |
| if (!ioreq->req.nr_segments) { |
| break; |
| } |
| |
| block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct, |
| ioreq->v.size, |
| ioreq->req.operation == BLKIF_OP_WRITE ? |
| BLOCK_ACCT_WRITE : BLOCK_ACCT_FLUSH); |
| ioreq->aio_inflight++; |
| blk_aio_pwritev(blkdev->blk, ioreq->start, &ioreq->v, 0, |
| qemu_aio_complete, ioreq); |
| break; |
| case BLKIF_OP_DISCARD: |
| { |
| struct blkif_request_discard *discard_req = (void *)&ioreq->req; |
| ioreq->aio_inflight++; |
| blk_aio_pdiscard(blkdev->blk, |
| discard_req->sector_number << BDRV_SECTOR_BITS, |
| discard_req->nr_sectors << BDRV_SECTOR_BITS, |
| 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; |
| } |
| /* Prevent the compiler from accessing the on-ring fields instead. */ |
| barrier(); |
| 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) { |
| |
| switch (ioreq->req.operation) { |
| case BLKIF_OP_READ: |
| block_acct_invalid(blk_get_stats(blkdev->blk), |
| BLOCK_ACCT_READ); |
| break; |
| case BLKIF_OP_WRITE: |
| block_acct_invalid(blk_get_stats(blkdev->blk), |
| BLOCK_ACCT_WRITE); |
| break; |
| case BLKIF_OP_FLUSH_DISKCACHE: |
| block_acct_invalid(blk_get_stats(blkdev->blk), |
| BLOCK_ACCT_FLUSH); |
| default: |
| break; |
| }; |
| |
| 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 (xengnttab_set_max_grants(xendev->gnttabdev, |
| MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) { |
| xen_be_printf(xendev, 0, "xengnttab_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 = "<unset>"; |
| blkdev->filename = blkdev->params; |
| } |
| } |
| if (!strcmp("aio", blkdev->fileproto)) { |
| blkdev->fileproto = "raw"; |
| } |
| if (!strcmp("vhd", blkdev->fileproto)) { |
| blkdev->fileproto = "vpc"; |
| } |
| 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; |
| bool writethrough = true; |
| |
| /* read-only ? */ |
| if (blkdev->directiosafe) { |
| qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO; |
| } else { |
| qflags = 0; |
| writethrough = false; |
| } |
| 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; |
| QDict *options = NULL; |
| |
| if (strcmp(blkdev->fileproto, "<unset>")) { |
| options = qdict_new(); |
| qdict_put(options, "driver", qstring_from_str(blkdev->fileproto)); |
| } |
| |
| /* setup via xenbus -> create new block driver instance */ |
| xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n"); |
| blkdev->blk = blk_new_open(blkdev->filename, NULL, options, |
| qflags, &local_err); |
| if (!blkdev->blk) { |
| xen_be_printf(&blkdev->xendev, 0, "error: %s\n", |
| error_get_pretty(local_err)); |
| error_free(local_err); |
| return -1; |
| } |
| blk_set_enable_write_cache(blkdev->blk, !writethrough); |
| } else { |
| /* setup via qemu cmdline -> already setup for us */ |
| xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline setup)\n"); |
| blkdev->blk = blk_by_legacy_dinfo(blkdev->dinfo); |
| if (blk_is_read_only(blkdev->blk) && !readonly) { |
| xen_be_printf(&blkdev->xendev, 0, "Unexpected read-only drive"); |
| blkdev->blk = NULL; |
| return -1; |
| } |
| /* blkdev->blk is not create by us, we get a reference |
| * so we can blk_unref() unconditionally */ |
| blk_ref(blkdev->blk); |
| } |
| blk_attach_dev_nofail(blkdev->blk, blkdev); |
| blkdev->file_size = blk_getlength(blkdev->blk); |
| if (blkdev->file_size < 0) { |
| BlockDriverState *bs = blk_bs(blkdev->blk); |
| const char *drv_name = bs ? bdrv_get_format_name(bs) : NULL; |
| xen_be_printf(&blkdev->xendev, 1, "blk_getlength: %d (%s) | drv %s\n", |
| (int)blkdev->file_size, strerror(-blkdev->file_size), |
| drv_name ?: "-"); |
| 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 = xengnttab_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, |
| batch_maps ? |
| (GDestroyNotify)g_free : |
| (GDestroyNotify)destroy_grant); |
| blkdev->persistent_regions = NULL; |
| 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->blk) { |
| blk_detach_dev(blkdev->blk, blkdev); |
| blk_unref(blkdev->blk); |
| blkdev->blk = NULL; |
| } |
| xen_be_unbind_evtchn(&blkdev->xendev); |
| |
| if (blkdev->sring) { |
| xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, 1); |
| blkdev->cnt_map--; |
| blkdev->sring = NULL; |
| } |
| |
| /* |
| * Unmap persistent grants before switching to the closed state |
| * so the frontend can free them. |
| * |
| * In the !batch_maps case g_tree_destroy will take care of unmapping |
| * the grant, but in the batch_maps case we need to iterate over every |
| * region in persistent_regions and unmap it. |
| */ |
| if (blkdev->feature_persistent) { |
| g_tree_destroy(blkdev->persistent_gnts); |
| assert(batch_maps || blkdev->persistent_gnt_count == 0); |
| if (batch_maps) { |
| blkdev->persistent_gnt_count = 0; |
| g_slist_foreach(blkdev->persistent_regions, |
| (GFunc)remove_persistent_region, blkdev); |
| g_slist_free(blkdev->persistent_regions); |
| } |
| blkdev->feature_persistent = false; |
| } |
| } |
| |
| static int blk_free(struct XenDevice *xendev) |
| { |
| struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); |
| struct ioreq *ioreq; |
| |
| if (blkdev->blk || blkdev->sring) { |
| blk_disconnect(xendev); |
| } |
| |
| 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, |
| }; |
