xen_disk is a pure userspace blkback implementation that can be used to
provided a disk backend called qdisk.
It is particularly useful with a dom0 kernel that doesn't have blktap2
(Linux 2.6.37).
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
diff --git a/hw/xen_backend.h b/hw/xen_backend.h
index 7e89ef4..c48c593 100644
--- a/hw/xen_backend.h
+++ b/hw/xen_backend.h
@@ -89,6 +89,7 @@ void xen_be_printf(struct XenDevice *xendev, int msg_level,
const char *fmt, ...
extern struct XenDevOps xen_console_ops; /* xen_console.c */
extern struct XenDevOps xen_kbdmouse_ops; /* xen_framebuffer.c */
extern struct XenDevOps xen_framebuffer_ops; /* xen_framebuffer.c */
+extern struct XenDevOps xen_blkdev_ops; /* xen_disk.c */
void xen_init_display(int domid);
diff --git a/hw/xen_blkif.h b/hw/xen_blkif.h
new file mode 100644
index 0000000..ca3a65b
--- /dev/null
+++ b/hw/xen_blkif.h
@@ -0,0 +1,103 @@
+#ifndef __XEN_BLKIF_H__
+#define __XEN_BLKIF_H__
+
+#include <xen/io/ring.h>
+#include <xen/io/blkif.h>
+#include <xen/io/protocols.h>
+
+/* Not a real protocol. Used to generate ring structs which contain
+ * the elements common to all protocols only. This way we get a
+ * compiler-checkable way to use common struct elements, so we can
+ * avoid using switch(protocol) in a number of places. */
+struct blkif_common_request {
+ char dummy;
+};
+struct blkif_common_response {
+ char dummy;
+};
+
+/* i386 protocol version */
+#pragma pack(push, 4)
+struct blkif_x86_32_request {
+ uint8_t operation; /* BLKIF_OP_??? */
+ uint8_t nr_segments; /* number of segments */
+ blkif_vdev_t handle; /* only for read/write requests */
+ uint64_t id; /* private guest value, echoed in resp */
+ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
+ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+};
+struct blkif_x86_32_response {
+ uint64_t id; /* copied from request */
+ uint8_t operation; /* copied from request */
+ int16_t status; /* BLKIF_RSP_??? */
+};
+typedef struct blkif_x86_32_request blkif_x86_32_request_t;
+typedef struct blkif_x86_32_response blkif_x86_32_response_t;
+#pragma pack(pop)
+
+/* x86_64 protocol version */
+struct blkif_x86_64_request {
+ uint8_t operation; /* BLKIF_OP_??? */
+ uint8_t nr_segments; /* number of segments */
+ blkif_vdev_t handle; /* only for read/write requests */
+ uint64_t __attribute__((__aligned__(8))) id;
+ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
+ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+};
+struct blkif_x86_64_response {
+ uint64_t __attribute__((__aligned__(8))) id;
+ uint8_t operation; /* copied from request */
+ int16_t status; /* BLKIF_RSP_??? */
+};
+typedef struct blkif_x86_64_request blkif_x86_64_request_t;
+typedef struct blkif_x86_64_response blkif_x86_64_response_t;
+
+DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct
blkif_common_response);
+DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct
blkif_x86_32_response);
+DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct
blkif_x86_64_response);
+
+union blkif_back_rings {
+ blkif_back_ring_t native;
+ blkif_common_back_ring_t common;
+ blkif_x86_32_back_ring_t x86_32;
+ blkif_x86_64_back_ring_t x86_64;
+};
+typedef union blkif_back_rings blkif_back_rings_t;
+
+enum blkif_protocol {
+ BLKIF_PROTOCOL_NATIVE = 1,
+ BLKIF_PROTOCOL_X86_32 = 2,
+ BLKIF_PROTOCOL_X86_64 = 3,
+};
+
+static inline void blkif_get_x86_32_req(blkif_request_t *dst,
blkif_x86_32_request_t *src)
+{
+ int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
+
+ dst->operation = src->operation;
+ dst->nr_segments = src->nr_segments;
+ dst->handle = src->handle;
+ dst->id = src->id;
+ dst->sector_number = src->sector_number;
+ if (n > src->nr_segments)
+ n = src->nr_segments;
+ for (i = 0; i < n; i++)
+ dst->seg[i] = src->seg[i];
+}
+
+static inline void blkif_get_x86_64_req(blkif_request_t *dst,
blkif_x86_64_request_t *src)
+{
+ int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
+
+ dst->operation = src->operation;
+ dst->nr_segments = src->nr_segments;
+ dst->handle = src->handle;
+ dst->id = src->id;
+ dst->sector_number = src->sector_number;
+ if (n > src->nr_segments)
+ n = src->nr_segments;
+ for (i = 0; i < n; i++)
+ dst->seg[i] = src->seg[i];
+}
+
+#endif /* __XEN_BLKIF_H__ */
diff --git a/hw/xen_disk.c b/hw/xen_disk.c
new file mode 100644
index 0000000..38b5fbf
--- /dev/null
+++ b/hw/xen_disk.c
@@ -0,0 +1,783 @@
+/*
+ * xen paravirt block device backend
+ *
+ * (c) Gerd Hoffmann <kraxel@xxxxxxxxxx>
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <inttypes.h>
+#include <time.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/uio.h>
+
+#include <xs.h>
+#include <xenctrl.h>
+#include <xen/io/xenbus.h>
+
+#include "hw.h"
+#include "block_int.h"
+#include "qemu-char.h"
+#include "xen_blkif.h"
+#include "xen_backend.h"
+#include "sysemu.h"
+
+/* ------------------------------------------------------------- */
+
+static int syncwrite = 1;
+static int batch_maps = 0;
+
+static int max_requests = 32;
+static int use_aio = 0;
+
+/* ------------------------------------------------------------- */
+
+#define BLOCK_SIZE 512
+#define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
+
+struct ioreq {
+ blkif_request_t req;
+ int16_t status;
+
+ /* parsed request */
+ off_t start;
+ QEMUIOVector v;
+ int presync;
+ int postsync;
+
+ /* 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;
+
+ /* aio status */
+ int aio_inflight;
+ int aio_errors;
+
+ struct XenBlkDev *blkdev;
+ LIST_ENTRY(ioreq) list;
+};
+
+struct XenBlkDev {
+ struct XenDevice xendev; /* must be first */
+ char *params;
+ char *mode;
+ char *type;
+ char *dev;
+ char *devtype;
+ 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 */
+ LIST_HEAD(inflight_head, ioreq) inflight;
+ LIST_HEAD(finished_head, ioreq) finished;
+ LIST_HEAD(freelist_head, ioreq) freelist;
+ int requests_total;
+ int requests_inflight;
+ int requests_finished;
+
+ /* qemu block driver */
+ int index;
+ BlockDriverState *bs;
+ QEMUBH *bh;
+};
+
+/* ------------------------------------------------------------- */
+
+static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
+{
+ struct ioreq *ioreq = NULL;
+
+ if (LIST_EMPTY(&blkdev->freelist)) {
+ if (blkdev->requests_total >= max_requests)
+ goto out;
+ /* allocate new struct */
+ ioreq = qemu_mallocz(sizeof(*ioreq));
+ ioreq->blkdev = blkdev;
+ blkdev->requests_total++;
+ qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ } else {
+ /* get one from freelist */
+ ioreq = LIST_FIRST(&blkdev->freelist);
+ LIST_REMOVE(ioreq, list);
+ qemu_iovec_reset(&ioreq->v);
+ }
+ LIST_INSERT_HEAD(&blkdev->inflight, ioreq, list);
+ blkdev->requests_inflight++;
+
+out:
+ return ioreq;
+}
+
+static void ioreq_finish(struct ioreq *ioreq)
+{
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+
+ LIST_REMOVE(ioreq, list);
+ LIST_INSERT_HEAD(&blkdev->finished, ioreq, list);
+ blkdev->requests_inflight--;
+ blkdev->requests_finished++;
+}
+
+static void ioreq_release(struct ioreq *ioreq)
+{
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+
+ LIST_REMOVE(ioreq, list);
+ memset(ioreq, 0, sizeof(*ioreq));
+ ioreq->blkdev = blkdev;
+ LIST_INSERT_HEAD(&blkdev->freelist, ioreq, list);
+ blkdev->requests_finished--;
+}
+
+/*
+ * 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_WRITE_BARRIER:
+ if (!syncwrite)
+ ioreq->presync = ioreq->postsync = 1;
+ /* fall through */
+ case BLKIF_OP_WRITE:
+ ioreq->prot = PROT_READ; /* from memory */
+ if (syncwrite)
+ ioreq->postsync = 1;
+ break;
+ 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)
+{
+ int gnt = ioreq->blkdev->xendev.gnttabdev;
+ int i;
+
+ if (ioreq->v.niov == 0)
+ return;
+ if (batch_maps) {
+ if (!ioreq->pages)
+ return;
+ if (xc_gnttab_munmap(xen_xc, gnt, ioreq->pages, ioreq->v.niov) != 0)
+ xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed:
%s\n",
+ strerror(errno));
+ ioreq->blkdev->cnt_map -= ioreq->v.niov;
+ ioreq->pages = NULL;
+ } else {
+ for (i = 0; i < ioreq->v.niov; i++) {
+ if (!ioreq->page[i])
+ continue;
+ if (xc_gnttab_munmap(xen_xc, 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;
+ }
+ }
+}
+
+static int ioreq_map(struct ioreq *ioreq)
+{
+ int gnt = ioreq->blkdev->xendev.gnttabdev;
+ int i;
+
+ if (ioreq->v.niov == 0)
+ return 0;
+ if (batch_maps) {
+ ioreq->pages = xc_gnttab_map_grant_refs
+ (xen_xc, gnt, ioreq->v.niov, ioreq->domids, ioreq->refs,
ioreq->prot);
+ if (ioreq->pages == NULL) {
+ xen_be_printf(&ioreq->blkdev->xendev, 0,
+ "can't map %d grant refs (%s, %d maps)\n",
+ ioreq->v.niov, strerror(errno),
ioreq->blkdev->cnt_map);
+ return -1;
+ }
+ for (i = 0; i < ioreq->v.niov; i++)
+ ioreq->v.iov[i].iov_base = ioreq->pages + i * XC_PAGE_SIZE +
+ (uintptr_t)ioreq->v.iov[i].iov_base;
+ ioreq->blkdev->cnt_map += ioreq->v.niov;
+ } else {
+ for (i = 0; i < ioreq->v.niov; i++) {
+ ioreq->page[i] = xc_gnttab_map_grant_ref
+ (xen_xc, gnt, ioreq->domids[i], ioreq->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",
+ ioreq->refs[i], strerror(errno),
ioreq->blkdev->cnt_map);
+ ioreq_unmap(ioreq);
+ return -1;
+ }
+ ioreq->v.iov[i].iov_base = ioreq->page[i] +
(uintptr_t)ioreq->v.iov[i].iov_base;
+ ioreq->blkdev->cnt_map++;
+ }
+ }
+ return 0;
+}
+
+static int ioreq_runio_qemu_sync(struct ioreq *ioreq)
+{
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+ int i, rc, len = 0;
+ off_t pos;
+
+ if (ioreq_map(ioreq) == -1)
+ goto err;
+ if (ioreq->presync)
+ bdrv_flush(blkdev->bs);
+
+ switch (ioreq->req.operation) {
+ case BLKIF_OP_READ:
+ pos = ioreq->start;
+ for (i = 0; i < ioreq->v.niov; i++) {
+ rc = bdrv_read(blkdev->bs, pos / BLOCK_SIZE,
+ ioreq->v.iov[i].iov_base,
+ ioreq->v.iov[i].iov_len / BLOCK_SIZE);
+ if (rc != 0) {
+ xen_be_printf(&blkdev->xendev, 0, "rd I/O error (%p, len
%zd)\n",
+ ioreq->v.iov[i].iov_base,
+ ioreq->v.iov[i].iov_len);
+ goto err;
+ }
+ len += ioreq->v.iov[i].iov_len;
+ pos += ioreq->v.iov[i].iov_len;
+ }
+ break;
+ case BLKIF_OP_WRITE:
+ case BLKIF_OP_WRITE_BARRIER:
+ pos = ioreq->start;
+ for (i = 0; i < ioreq->v.niov; i++) {
+ rc = bdrv_write(blkdev->bs, pos / BLOCK_SIZE,
+ ioreq->v.iov[i].iov_base,
+ ioreq->v.iov[i].iov_len / BLOCK_SIZE);
+ if (rc != 0) {
+ xen_be_printf(&blkdev->xendev, 0, "wr I/O error (%p, len
%zd)\n",
+ ioreq->v.iov[i].iov_base,
+ ioreq->v.iov[i].iov_len);
+ goto err;
+ }
+ len += ioreq->v.iov[i].iov_len;
+ pos += ioreq->v.iov[i].iov_len;
+ }
+ break;
+ default:
+ /* unknown operation (shouldn't happen -- parse catches this) */
+ goto err;
+ }
+
+ if (ioreq->postsync)
+ bdrv_flush(blkdev->bs);
+ ioreq->status = BLKIF_RSP_OKAY;
+
+ ioreq_unmap(ioreq);
+ ioreq_finish(ioreq);
+ return 0;
+
+err:
+ ioreq->status = BLKIF_RSP_ERROR;
+ return -1;
+}
+
+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->aio_inflight > 0)
+ return;
+
+ ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
+ ioreq_unmap(ioreq);
+ ioreq_finish(ioreq);
+ qemu_bh_schedule(ioreq->blkdev->bh);
+}
+
+static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
+{
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+
+ if (ioreq_map(ioreq) == -1)
+ goto err;
+
+ ioreq->aio_inflight++;
+ if (ioreq->presync)
+ bdrv_flush(blkdev->bs); /* FIXME: aio_flush() ??? */
+
+ switch (ioreq->req.operation) {
+ case BLKIF_OP_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_WRITE_BARRIER:
+ ioreq->aio_inflight++;
+ bdrv_aio_writev(blkdev->bs, ioreq->start / BLOCK_SIZE,
+ &ioreq->v, ioreq->v.size / BLOCK_SIZE,
+ qemu_aio_complete, ioreq);
+ break;
+ default:
+ /* unknown operation (shouldn't happen -- parse catches this) */
+ goto err;
+ }
+
+ if (ioreq->postsync)
+ bdrv_flush(blkdev->bs); /* FIXME: aio_flush() ??? */
+ qemu_aio_complete(ioreq, 0);
+
+ return 0;
+
+err:
+ 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,
blkdev->rings.x86_32.rsp_prod_pvt);
+ break;
+ case BLKIF_PROTOCOL_X86_64:
+ dst = RING_GET_RESPONSE(&blkdev->rings.x86_64,
blkdev->rings.x86_64.rsp_prod_pvt);
+ break;
+ default:
+ dst = NULL;
+ }
+ 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 (!LIST_EMPTY(&blkdev->finished)) {
+ ioreq = LIST_FIRST(&blkdev->finished);
+ send_notify += blk_send_response_one(ioreq);
+ ioreq_release(ioreq);
+ }
+ 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, rc));
+ break;
+ case BLKIF_PROTOCOL_X86_64:
+ blkif_get_x86_64_req(&ioreq->req,
RING_GET_REQUEST(&blkdev->rings.x86_64, 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'. */
+
+ if (use_aio)
+ 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);
+ continue;
+ }
+
+ if (use_aio) {
+ /* run i/o in aio mode */
+ ioreq_runio_qemu_aio(ioreq);
+ } else {
+ /* run i/o in sync mode */
+ ioreq_runio_qemu_sync(ioreq);
+ }
+ }
+ if (!use_aio)
+ blk_send_response_all(blkdev);
+
+ 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);
+}
+
+static void blk_alloc(struct XenDevice *xendev)
+{
+ struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+
+ LIST_INIT(&blkdev->inflight);
+ LIST_INIT(&blkdev->finished);
+ LIST_INIT(&blkdev->freelist);
+ blkdev->bh = qemu_bh_new(blk_bh, blkdev);
+ if (xen_mode != XEN_EMULATE)
+ batch_maps = 1;
+}
+
+static int blk_init(struct XenDevice *xendev)
+{
+ struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+ int mode, qflags, have_barriers, info = 0;
+ char *h;
+
+ /* read xenstore entries */
+ if (blkdev->params == NULL) {
+ blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params");
+ 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 (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");
+
+ /* do we have all we need? */
+ if (blkdev->params == NULL ||
+ blkdev->mode == NULL ||
+ blkdev->type == NULL ||
+ blkdev->dev == NULL)
+ return -1;
+
+ /* read-only ? */
+ if (strcmp(blkdev->mode, "w") == 0) {
+ mode = O_RDWR;
+ qflags = BDRV_O_RDWR;
+ } else {
+ mode = O_RDONLY;
+ qflags = BDRV_O_RDONLY;
+ info |= VDISK_READONLY;
+ }
+
+ /* cdrom ? */
+ if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom"))
+ info |= VDISK_CDROM;
+
+ /* init qemu block driver */
+ blkdev->index = (blkdev->xendev.dev - 202 * 256) / 16;
+ blkdev->index = drive_get_index(IF_XEN, 0, blkdev->index);
+ if (blkdev->index == -1) {
+ /* setup via xenbus -> create new block driver instance */
+ xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");
+ blkdev->bs = bdrv_new(blkdev->dev);
+ if (blkdev->bs) {
+ if (bdrv_open2(blkdev->bs, blkdev->filename, qflags,
+ bdrv_find_format(blkdev->fileproto)) != 0) {
+ bdrv_delete(blkdev->bs);
+ blkdev->bs = NULL;
+ }
+ }
+ if (!blkdev->bs)
+ 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 = drives_table[blkdev->index].bdrv;
+ }
+ blkdev->file_blk = BLOCK_SIZE;
+ 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),
+ blkdev->bs->drv ? blkdev->bs->drv->format_name : "-");
+ blkdev->file_size = 0;
+ }
+ have_barriers = blkdev->bs->drv && blkdev->bs->drv->bdrv_flush ? 1 : 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 info */
+ xenstore_write_be_int(&blkdev->xendev, "feature-barrier", have_barriers);
+ xenstore_write_be_int(&blkdev->xendev, "info", info);
+ xenstore_write_be_int(&blkdev->xendev, "sector-size",
blkdev->file_blk);
+ xenstore_write_be_int(&blkdev->xendev, "sectors",
+ blkdev->file_size / blkdev->file_blk);
+ return 0;
+}
+
+static int blk_connect(struct XenDevice *xendev)
+{
+ struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+
+ 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;
+
+ 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(xen_xc, 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, 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, sring_x86_64, XC_PAGE_SIZE);
+ break;
+ }
+ }
+
+ 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) {
+ if (blkdev->index == -1) {
+ /* close/delete only if we created it ourself */
+ bdrv_close(blkdev->bs);
+ bdrv_delete(blkdev->bs);
+ }
+ blkdev->bs = NULL;
+ }
+ xen_be_unbind_evtchn(&blkdev->xendev);
+
+ if (blkdev->sring) {
+ xc_gnttab_munmap(xen_xc, 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;
+
+ while (!LIST_EMPTY(&blkdev->freelist)) {
+ ioreq = LIST_FIRST(&blkdev->freelist);
+ LIST_REMOVE(ioreq, list);
+ qemu_iovec_destroy(&ioreq->v);
+ qemu_free(ioreq);
+ }
+
+ qemu_free(blkdev->params);
+ qemu_free(blkdev->mode);
+ qemu_free(blkdev->type);
+ qemu_free(blkdev->dev);
+ qemu_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,
+};
diff --git a/hw/xen_machine_fv.c b/hw/xen_machine_fv.c
index 79880a8..7eb3792 100644
--- a/hw/xen_machine_fv.c
+++ b/hw/xen_machine_fv.c
@@ -368,6 +368,7 @@ static void xen_init_fv(ram_addr_t ram_size, int
vga_ram_size,
exit(1);
}
xen_be_register("console", &xen_console_ops);
+ xen_be_register("qdisk", &xen_blkdev_ops);
pc_machine.init(ram_size, vga_ram_size, boot_device,
kernel_filename, kernel_cmdline, initrd_filename,
diff --git a/hw/xen_machine_pv.c b/hw/xen_machine_pv.c
index 34fe4d4..b2475ba 100644
--- a/hw/xen_machine_pv.c
+++ b/hw/xen_machine_pv.c
@@ -69,6 +69,7 @@ static void xen_init_pv(ram_addr_t ram_size, int vga_ram_size,
xen_be_register("console", &xen_console_ops);
xen_be_register("vkbd", &xen_kbdmouse_ops);
xen_be_register("vfb", &xen_framebuffer_ops);
+ xen_be_register("qdisk", &xen_blkdev_ops);
/* setup framebuffer */
xen_init_display(xen_domid);
diff --git a/sysemu.h b/sysemu.h
index 87b278b..66b8ab2 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -127,7 +127,7 @@ extern unsigned int nb_prom_envs;
typedef enum {
IF_BLKTAP,
- IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO
+ IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO, IF_XEN
} BlockInterfaceType;
typedef enum {
diff --git a/vl.c b/vl.c
index a90da8c..2fb5f82 100644
--- a/vl.c
+++ b/vl.c
@@ -2396,6 +2396,9 @@ int drive_init(struct drive_opt *arg, int snapshot, void
*opaque)
} else if (!strcmp(buf, "mtd")) {
type = IF_MTD;
max_devs = 0;
+ } else if (!strcmp(buf, "xen")) {
+ type = IF_XEN;
+ max_devs = 0;
} else if (!strcmp(buf, "sd")) {
type = IF_SD;
max_devs = 0;
@@ -2615,6 +2618,7 @@ int drive_init(struct drive_opt *arg, int snapshot, void
*opaque)
switch(type) {
case IF_IDE:
+ case IF_XEN:
case IF_SCSI:
switch(media) {
case MEDIA_DISK:
diff --git a/xen-hooks.mak b/xen-hooks.mak
index 93f4402..891d1aa 100644
--- a/xen-hooks.mak
+++ b/xen-hooks.mak
@@ -30,6 +30,7 @@ OBJS += xen_machine_pv.o
OBJS += xen_backend.o
OBJS += xenfb.o
OBJS += xen_console.o
+OBJS += xen_disk.o
OBJS += xen_machine_fv.o
OBJS += exec-dm.o
OBJS += pci_emulation.o
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