[Spice-devel] [PATCH 12/12] block: add spice block device backend
Marc-André Lureau
marcandre.lureau at gmail.com
Thu Jun 20 10:46:11 PDT 2013
Signed-off-by: Marc-André Lureau <marcandre.lureau at redhat.com>
---
block/Makefile.objs | 1 +
block/spice.c | 523 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 524 insertions(+)
create mode 100644 block/spice.c
diff --git a/block/Makefile.objs b/block/Makefile.objs
index 5890b5c..0170011 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -16,6 +16,7 @@ block-obj-$(CONFIG_CURL) += curl.o
block-obj-$(CONFIG_RBD) += rbd.o
block-obj-$(CONFIG_GLUSTERFS) += gluster.o
block-obj-$(CONFIG_LIBSSH2) += ssh.o
+common-obj-$(CONFIG_SPICE) += spice.o
endif
common-obj-y += stream.o
diff --git a/block/spice.c b/block/spice.c
new file mode 100644
index 0000000..b2c669d
--- /dev/null
+++ b/block/spice.c
@@ -0,0 +1,523 @@
+/*
+ * Spice block backend for QEMU.
+ *
+ * Copyright (C) 2013 Red Hat, Inc.
+ * Author: Marc-André Lureau <marcandre.lureau at redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <spice/protocol.h>
+
+#include "nbd-client.h"
+#include "ui/qemu-spice.h"
+#include "block/block_int.h"
+#include "qemu/sockets.h"
+#include "qemu/uri.h"
+#include "qapi/qmp/qint.h"
+#include "sysemu/sysemu.h"
+#include "sysemu/char.h"
+
+#ifndef DEBUG_SPICE
+#define DEBUG_SPICE 0
+#endif
+
+#define SOCKET_CHR 0
+#define SOCKET_NBD 1
+
+#define DPRINTF(fmt, ...) \
+ do { \
+ if (DEBUG_SPICE) { \
+ fprintf(stderr, "spice: %-15s " fmt "\n", \
+ __func__, ##__VA_ARGS__); \
+ } \
+ } while (0)
+
+typedef struct Buffer {
+ uint8_t data[4096];
+ uint8_t *p;
+ char left;
+} Buffer;
+
+typedef struct BDRVSpiceState {
+ BlockDriverState *bs;
+ NbdClientSession client;
+ char *export;
+
+ /* our spicechr-fd pipe */
+ int sv[2];
+ Buffer readb;
+ Buffer writeb;
+
+ int aio_count;
+ CharDriverState *chr;
+ guint chr_watch;
+
+ Coroutine *coroutine;
+ bool need_read;
+ bool need_write;
+ bool opened;
+} BDRVSpiceState;
+
+static void nbd_read_handler(void *opaque);
+static void update_chr_handlers(BDRVSpiceState *s);
+
+static int parse_uri(const char *filename, QDict *options, Error **errp)
+{
+ URI *uri = NULL;
+
+ uri = uri_parse(filename);
+ if (!uri) {
+ return -EINVAL;
+ }
+
+ if (strcmp(uri->scheme, "spicebd") != 0) {
+ error_setg(errp, "URI scheme must be 'spicebd'");
+ goto err;
+ }
+
+ if (uri->path && *uri->path) {
+ qdict_put(options, "export", qstring_from_str(uri->path));
+ }
+
+ uri_free(uri);
+ return 0;
+
+ err:
+ if (uri) {
+ uri_free(uri);
+ }
+ return -EINVAL;
+}
+
+static void spice_parse_filename(const char *filename, QDict *options,
+ Error **errp)
+{
+ if (qdict_haskey(options, "export")) {
+ error_setg(errp, "export cannot be used at the same time "
+ "as a file option");
+ return;
+ }
+
+ parse_uri(filename, options, errp);
+}
+
+static void co_restart(void *opaque)
+{
+ BDRVSpiceState *s = opaque;
+
+ qemu_coroutine_enter(s->coroutine, NULL);
+}
+
+static void close_socketpair(BDRVSpiceState *s)
+{
+ /* this is catching various error paths, and deals with it by
+ closing socketpair, so that both ends can cleanup. It may need
+ more specific error handling. */
+ DPRINTF("closing socketpair");
+ if (!s->opened) {
+ return;
+ }
+
+ if (s->sv[SOCKET_NBD] >= 0) {
+ qemu_aio_set_fd_handler(s->sv[SOCKET_NBD], NULL, NULL, NULL, NULL);
+ closesocket(s->sv[SOCKET_NBD]);
+ s->sv[SOCKET_NBD] = -1;
+ }
+
+ if (s->sv[SOCKET_CHR] >= 0) {
+ qemu_aio_set_fd_handler(s->sv[SOCKET_CHR], NULL, NULL, NULL, NULL);
+ closesocket(s->sv[SOCKET_CHR]);
+ s->sv[SOCKET_CHR] = -1;
+ }
+
+ s->opened = FALSE;
+ if (s->coroutine && s->coroutine != qemu_coroutine_self()) {
+ co_restart(s);
+ }
+}
+
+static int chardev_can_read(void *opaque)
+{
+ BDRVSpiceState *s = opaque;
+ int retval = 0;
+
+ GPollFD pfd = {
+ .fd = s->sv[SOCKET_CHR],
+ .events = G_IO_OUT
+ };
+ g_poll(&pfd, 1, 0);
+ if (pfd.revents & G_IO_OUT) {
+ retval = s->writeb.left == 0 ? sizeof(s->writeb.data) : 0;
+ }
+
+ return retval;
+}
+
+static void chardev_read(void *opaque, const uint8_t *buf, int size)
+{
+ BDRVSpiceState *s = opaque;
+ int written;
+
+ DPRINTF("reply from client %d", size);
+ written = write(s->sv[SOCKET_CHR], buf, size);
+ if (written == -1) {
+ if (errno != EAGAIN) {
+ close_socketpair(s);
+ return;
+ } else {
+ written = 0;
+ }
+ }
+
+ if (s->writeb.left == 0) {
+ size -= written;
+ assert(size <= sizeof(s->writeb.data));
+ memcpy(s->writeb.data, buf, size);
+ s->writeb.p = s->writeb.data;
+ s->writeb.left = size;
+ } else {
+ s->writeb.left -= written;
+ s->writeb.p += written;
+ }
+
+ s->need_write = s->writeb.left > 0;
+ update_chr_handlers(s);
+}
+
+static void coroutine_fn co_init(void *opaque)
+{
+ BDRVSpiceState *s = opaque;
+ BlockDriverState *bs = s->bs;
+ int bdrv_flags;
+
+ DPRINTF("temporary coroutine for session initialization %p", s);
+
+ qemu_set_nonblock(s->sv[SOCKET_NBD]);
+ /* After session_init, the fd_handler is managed by nbd-client */
+ qemu_aio_set_fd_handler(s->sv[SOCKET_NBD], co_restart, NULL, NULL, s);
+ if (nbd_client_session_init(&s->client, bs,
+ s->sv[SOCKET_NBD], s->export) < 0) {
+ goto error;
+ }
+
+ bs->opaque = NULL;
+
+ while (bs->child) {
+ bs = bs->child;
+ }
+
+ if (bdrv_in_use(bs)) {
+ goto error;
+ }
+ if (!bdrv_dev_has_removable_media(bs)) {
+ goto error;
+ }
+ if (bdrv_dev_is_medium_locked(bs) && !bdrv_dev_is_tray_open(bs)) {
+ bdrv_dev_eject_request(bs, true);
+ }
+
+ /* could the switch be racy with other threads and need to be
+ called from main loop ? */
+ bdrv_close(bs);
+
+ QDict *options = NULL;
+ bs->opaque = s;
+
+ bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
+ if (bdrv_is_snapshot(bs)) {
+ bdrv_flags |= BDRV_O_SNAPSHOT;
+ options = qdict_new();
+ qdict_put(options, "snapshot.size", qint_from_int(s->client.size));
+ }
+
+ DPRINTF("reopen %p", s);
+ if (bdrv_open(bs, "spicebd:", options, bdrv_flags, NULL) < 0) {
+ DPRINTF("failed to re-open spicebd");
+ goto error;
+ }
+
+ goto end;
+
+error:
+ close_socketpair(s);
+end:
+ s->coroutine = NULL;
+ DPRINTF("end of temporary coroutine");
+}
+
+static void spice_init(BDRVSpiceState *s)
+{
+ if (s->opened) {
+ return;
+ }
+
+ s->opened = TRUE;
+ /* gosh that sucks :) */
+ if (socketpair(PF_UNIX, SOCK_STREAM, 0, s->sv) == -1) {
+ fprintf(stderr, "failed to create socketpair\n");
+ return;
+ }
+
+ s->need_read = TRUE;
+ update_chr_handlers(s);
+
+ /* tell server we are ready */
+ qemu_chr_fe_event(s->chr, SPICE_PORT_EVENT_OPENED);
+ s->coroutine = qemu_coroutine_create(co_init);
+ qemu_coroutine_enter(s->coroutine, s);
+}
+
+static void chardev_event(void *opaque, int event)
+{
+ BDRVSpiceState *s = opaque;
+ DPRINTF("chardev_event %d", event);
+
+ switch (event) {
+ case CHR_EVENT_CLOSED:
+ DPRINTF("chardev close");
+ close_socketpair(s);
+ break;
+ case CHR_EVENT_BREAK:
+ DPRINTF("chardev break");
+ if (s->coroutine) {
+ DPRINTF("already waiting for incoming session");
+ return;
+ }
+ close_socketpair(s);
+ /* fall-through */
+ case CHR_EVENT_OPENED:
+ spice_init(s);
+ break;
+ default:
+ DPRINTF("unhandled chardev event %d", event);
+ }
+}
+
+static gboolean write_to_chr(GIOChannel *chan, GIOCondition cond,
+ void *opaque)
+{
+ BDRVSpiceState *s = opaque;
+ int r;
+
+ r = qemu_chr_fe_write(s->chr, s->readb.p, s->readb.left);
+ DPRINTF("write_to_chr %d/%d", r, s->readb.left);
+ if (r <= 0) {
+ close_socketpair(s);
+ return FALSE;
+ }
+
+ s->readb.p += r;
+ s->readb.left -= r;
+
+ if (s->readb.left > 0) {
+ if (!s->chr_watch) {
+ s->chr_watch = qemu_chr_fe_add_watch(s->chr, G_IO_OUT,
+ write_to_chr, s);
+ }
+ return TRUE;
+ } else {
+ s->need_read = TRUE;
+ update_chr_handlers(s);
+ }
+
+ return FALSE;
+}
+
+static void nbd_read_handler(void *opaque)
+{
+ BDRVSpiceState *s = opaque;
+
+ DPRINTF("read from nbd");
+
+ if (s->readb.left > 0) {
+ abort();
+ }
+
+ do {
+ s->readb.left = recv(s->sv[SOCKET_CHR], s->readb.data,
+ sizeof(s->readb.data), MSG_DONTWAIT);
+ } while (s->readb.left == -1 && errno == EAGAIN);
+
+ if (s->readb.left <= 0) {
+ close_socketpair(s);
+ return;
+ }
+
+ s->need_read = FALSE;
+ update_chr_handlers(s);
+
+ s->readb.p = s->readb.data;
+ write_to_chr(NULL, 0, s);
+}
+
+static void nbd_write_handler(void *opaque)
+{
+ BDRVSpiceState *s = opaque;
+
+ DPRINTF("resuming chardev_read left: %d", s->writeb.left);
+
+ chardev_read(s, s->writeb.data, s->writeb.left);
+}
+
+static void update_chr_handlers(BDRVSpiceState *s)
+{
+ qemu_aio_set_fd_handler(s->sv[SOCKET_CHR],
+ s->need_read ? nbd_read_handler : NULL,
+ s->need_write ? nbd_write_handler : NULL,
+ NULL, s);
+}
+
+static int spice_file_open(BlockDriverState *bs, QDict *options, int bdrv_flags)
+{
+ BDRVSpiceState *s = bs->opaque;
+ int ret = -1;
+
+ s->bs = bs;
+ if (s->opened) {
+ DPRINTF("re-open spicebd");
+ s->client.bs = bs;
+ return 0;
+ }
+
+ if (qdict_haskey(options, "export")) {
+ s->export = strdup(qdict_get_str(options, "export"));
+ qdict_del(options, "export");
+ }
+
+ DPRINTF("open %p flags=0x%x export=%s", s, bdrv_flags, s->export);
+ if (bdrv_flags & BDRV_O_RDWR) {
+ fprintf(stderr, "spicebd: only read-only supported\n");
+ return -1;
+ }
+
+ s->chr = qemu_chr_open_spice_vmc("nbd");
+ if (!s->chr) {
+ goto err;
+ }
+
+ qemu_chr_add_handlers(s->chr, chardev_can_read,
+ chardev_read, chardev_event, s);
+ spice_init(s);
+
+ return 0;
+
+ err:
+ return ret;
+}
+
+static void spice_close(BlockDriverState *bs)
+{
+ BDRVSpiceState *s = bs->opaque;
+
+ DPRINTF("spice close %p\n", s);
+
+ if (s == NULL) {
+ /* changing bd */
+ return;
+ }
+
+ s->bs = NULL;
+
+ nbd_client_session_close(&s->client);
+ close_socketpair(s);
+ assert(!s->coroutine); /* after close_socketpair */
+
+ if (s->chr) {
+ s->chr->chr_close(s->chr);
+ g_free(s->chr);
+ s->chr = NULL;
+ }
+
+ g_free(s->export);
+ s->export = NULL;
+}
+
+static coroutine_fn int spice_co_readv(BlockDriverState *bs,
+ int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov)
+{
+ BDRVSpiceState *s = bs->opaque;
+
+ return nbd_client_session_co_readv(&s->client, sector_num,
+ nb_sectors, qiov);
+}
+
+static coroutine_fn int spice_co_writev(BlockDriverState *bs,
+ int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov)
+{
+ BDRVSpiceState *s = bs->opaque;
+
+ return nbd_client_session_co_writev(&s->client, sector_num,
+ nb_sectors, qiov);
+}
+
+static coroutine_fn int spice_co_flush(BlockDriverState *bs)
+{
+ BDRVSpiceState *s = bs->opaque;
+
+ if (s == NULL) {
+ /* changing bd */
+ return -1;
+ }
+
+ return nbd_client_session_co_flush(&s->client);
+}
+
+static coroutine_fn int spice_co_discard(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors)
+{
+ BDRVSpiceState *s = bs->opaque;
+
+ return nbd_client_session_co_discard(&s->client, sector_num, nb_sectors);
+}
+
+static coroutine_fn int64_t spice_getlength(BlockDriverState *bs)
+{
+ BDRVSpiceState *s = bs->opaque;
+
+ DPRINTF("length=%" PRIi64, s->client.size);
+
+ return s->client.size;
+}
+
+static BlockDriver bdrv_spice = {
+ .format_name = "spicebd",
+ .protocol_name = "spicebd",
+ .instance_size = sizeof(BDRVSpiceState),
+ .bdrv_parse_filename = spice_parse_filename,
+ .bdrv_file_open = spice_file_open,
+ .bdrv_close = spice_close,
+ .bdrv_co_readv = spice_co_readv,
+ .bdrv_co_writev = spice_co_writev,
+ .bdrv_getlength = spice_getlength,
+ .bdrv_co_flush_to_os = spice_co_flush,
+ .bdrv_co_discard = spice_co_discard,
+};
+
+static void bdrv_spice_init(void)
+{
+ bdrv_register(&bdrv_spice);
+}
+
+block_init(bdrv_spice_init);
--
1.8.3.rc1.49.g8d97506
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