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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 20/27] tools/libxl: Infrastructure for writing a v2 stream
From: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
---
tools/libxl/Makefile | 2 +-
tools/libxl/libxl_internal.h | 33 +++
tools/libxl/libxl_stream_write.c | 536 ++++++++++++++++++++++++++++++++++++++
3 files changed, 570 insertions(+), 1 deletion(-)
create mode 100644 tools/libxl/libxl_stream_write.c
diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
index ca0ae3e..63e32f7 100644
--- a/tools/libxl/Makefile
+++ b/tools/libxl/Makefile
@@ -94,7 +94,7 @@ LIBXL_OBJS = flexarray.o libxl.o libxl_create.o libxl_dm.o
libxl_pci.o \
libxl_dom.o libxl_exec.o libxl_xshelp.o libxl_device.o \
libxl_internal.o libxl_utils.o libxl_uuid.o \
libxl_json.o libxl_aoutils.o libxl_numa.o libxl_vnuma.o
\
- libxl_stream_read.o \
+ libxl_stream_read.o libxl_stream_write.o \
libxl_save_callout.o _libxl_save_msgs_callout.o \
libxl_convert_callout.o \
libxl_qmp.o libxl_event.o libxl_fork.o $(LIBXL_OBJS-y)
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 5482950..82cd792 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -2868,6 +2868,38 @@ typedef void libxl__domain_suspend_cb(libxl__egc*,
typedef void libxl__save_device_model_cb(libxl__egc*,
libxl__domain_suspend_state*, int rc);
+/* State for writing a libxl migration v2 stream */
+typedef struct libxl__stream_write_state libxl__stream_write_state;
+
+struct libxl__stream_write_state {
+ /* filled by the user */
+ libxl__ao *ao;
+ int fd;
+ uint32_t domid;
+ void (*completion_callback)(libxl__egc *egc,
+ libxl__domain_suspend_state *dss,
+ int rc);
+ /* Private */
+ int rc;
+ int joined_rc;
+ size_t padding;
+ bool running;
+ libxl__datacopier_state dc;
+};
+
+_hidden void libxl__stream_write_start(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+
+_hidden void libxl__stream_write_abort(libxl__egc *egc,
+ libxl__stream_write_state *stream,
+ int rc);
+
+static inline bool libxl__stream_write_inuse(
+ const libxl__stream_write_state *stream)
+{
+ return stream->running;
+}
+
typedef struct libxl__logdirty_switch {
const char *cmd;
const char *cmd_path;
@@ -2907,6 +2939,7 @@ struct libxl__domain_suspend_state {
/* private for libxl__domain_save_device_model */
libxl__save_device_model_cb *save_dm_callback;
libxl__datacopier_state save_dm_datacopier;
+ libxl__stream_write_state sws;
};
diff --git a/tools/libxl/libxl_stream_write.c b/tools/libxl/libxl_stream_write.c
new file mode 100644
index 0000000..856d72e
--- /dev/null
+++ b/tools/libxl/libxl_stream_write.c
@@ -0,0 +1,536 @@
+/*
+ * Copyright (C) 2015 Citrix Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file 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 Lesser General Public License for more details.
+ */
+
+#include "libxl_osdeps.h" /* must come before any other headers */
+
+#include "libxl_internal.h"
+
+/*
+ * Infrastructure for writing a domain to a libxl migration v2 stream.
+ *
+ * Entry points from outside:
+ * - libxl__stream_write_start()
+ * - Start writing a stream from the start.
+ *
+ * In normal operation, there are two tasks running at once; this stream
+ * processing, and the the libxl-save-helper. check_stream_finished() is used
+ * to join all the tasks in both success and error cases.
+ *
+ * Nomenclature for event callbacks:
+ * - $FOO_done(): Completion callback for $FOO
+ * - write_$FOO(): Set up writing a $FOO
+ * - $BAR_header(): A $BAR record header only
+ * - $BAR_record(): A complete $BAR record with header and content
+ *
+ * The main loop for a plain VM writes:
+ * - Stream header
+ * - Libxc record
+ * - Toolstack record
+ * - if (hvm), Qemu record
+ * - End record
+ */
+
+static const uint8_t zero_padding[1U << REC_ALIGN_ORDER] = { 0 };
+
+static void stream_success(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void stream_failed(libxl__egc *egc,
+ libxl__stream_write_state *stream, int ret);
+static void stream_done(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+
+static void check_stream_finished(libxl__egc *egc,
+ libxl__domain_suspend_state *dcs,
+ int rc, const char *what);
+
+/* Event callbacks for plain VM. */
+static void stream_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+static void libxc_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+/* libxl__xc_domain_save_done() lives here, event-order wise. */
+static void write_toolstack_record(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void toolstack_record_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+static void write_emulator_record(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void emulator_body_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+static void emulator_padding_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+static void write_end_record(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void end_record_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+
+void libxl__stream_write_start(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__datacopier_state *dc = &stream->dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_hdr hdr = { 0 };
+ int ret = 0;
+
+ assert(!stream->running);
+ stream->running = true;
+
+ memset(dc, 0, sizeof(*dc));
+ dc->readwhat = "";
+ dc->copywhat = "suspend header";
+ dc->writewhat = "save/migration stream";
+ dc->ao = ao;
+ dc->readfd = -1;
+ dc->writefd = stream->fd;
+ dc->maxsz = INT_MAX;
+ dc->bytes_to_read = INT_MAX;
+ dc->callback = stream_header_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ hdr.ident = htobe64(RESTORE_STREAM_IDENT);
+ hdr.version = htobe32(RESTORE_STREAM_VERSION);
+ hdr.options = htobe32(0);
+
+ libxl__datacopier_prefixdata(egc, dc, &hdr, sizeof(hdr));
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+void libxl__stream_write_abort(libxl__egc *egc,
+ libxl__stream_write_state *stream, int rc)
+{
+ stream_failed(egc, stream, rc);
+}
+
+static void stream_success(libxl__egc *egc, libxl__stream_write_state *stream)
+{
+ stream->rc = 0;
+ stream->running = false;
+
+ stream_done(egc, stream);
+}
+
+static void stream_failed(libxl__egc *egc,
+ libxl__stream_write_state *stream, int rc)
+{
+ assert(rc);
+ stream->rc = rc;
+
+ if (stream->running) {
+ stream->running = false;
+ stream_done(egc, stream);
+ }
+}
+
+static void stream_done(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+
+ assert(!stream->running);
+
+ check_stream_finished(egc, dss, stream->rc, "stream");
+}
+
+static void check_stream_finished(libxl__egc *egc,
+ libxl__domain_suspend_state *dss,
+ int rc, const char *what)
+{
+ libxl__stream_write_state *stream = &dss->sws;
+ STATE_AO_GC(dss->ao);
+
+ LOG(INFO, "Task '%s' joining (rc %d)", what, rc);
+
+ if (rc && !stream->joined_rc) {
+ bool skip = false;
+ /* First reported failure from joining tasks. Tear everything down */
+ stream->joined_rc = rc;
+
+ if (libxl__stream_write_inuse(&dss->sws)) {
+ skip = true;
+ libxl__stream_write_abort(egc, &dss->sws, rc);
+ }
+
+ if (libxl__save_helper_inuse(&dss->shs)) {
+ skip = true;
+ libxl__save_helper_abort(egc, &dss->shs);
+ }
+
+ /* There is at least one more active task to join - wait for its
+ callback */
+ if ( skip )
+ return;
+ }
+
+ if (libxl__stream_write_inuse(&dss->sws))
+ LOG(DEBUG, "stream still in use");
+ else if (libxl__save_helper_inuse(&dss->shs))
+ LOG(DEBUG, "save/restore still in use");
+ else {
+ LOG(INFO, "Join complete: result %d", stream->joined_rc);
+ stream->completion_callback(egc, dss, stream->joined_rc);
+ }
+}
+
+static void stream_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_rec_hdr rec = { REC_TYPE_LIBXC_CONTEXT, 0 };
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ dc->copywhat = "suspend footer";
+ dc->writewhat = "save/migration stream";
+ dc->callback = libxc_header_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ libxl__datacopier_prefixdata(egc, dc, &rec, sizeof(rec));
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void libxc_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ libxl__xc_domain_save(egc, dss);
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void __attribute__((used))
+will_be_libxl__xc_domain_save_done(libxl__egc *egc, void *dss_void,
+ int rc, int retval, int errnoval)
+{
+ libxl__domain_suspend_state *dss = dss_void;
+ libxl__stream_write_state *stream = &dss->sws;
+ STATE_AO_GC(dss->ao);
+
+ if (rc)
+ goto err;
+
+ if (retval) {
+ LOGEV(ERROR, errnoval, "saving domain: %s",
+ dss->guest_responded ?
+ "domain responded to suspend request" :
+ "domain did not respond to suspend request");
+ if ( !dss->guest_responded )
+ rc = ERROR_GUEST_TIMEDOUT;
+ else
+ rc = ERROR_FAIL;
+ goto err;
+ }
+
+ write_toolstack_record(egc, stream);
+ return;
+
+ err:
+ assert(rc);
+ check_stream_finished(egc, dss, rc, "save/restore helper");
+}
+
+static void write_toolstack_record(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+ libxl__datacopier_state *dc = &stream->dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_rec_hdr rec = { REC_TYPE_XENSTORE_DATA, 0 };
+ int ret = 0;
+ uint8_t *toolstack_buf = NULL; /* We must free this. */
+ uint32_t toolstack_len, padding_len;
+
+ ret = libxl__toolstack_save(dss->domid, &toolstack_buf,
+ &toolstack_len, dss);
+ if (ret)
+ goto err;
+
+ dc->copywhat = "toolstack record";
+ dc->writewhat = "save/migration stream";
+ dc->callback = toolstack_record_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ rec.length = toolstack_len;
+
+ libxl__datacopier_prefixdata(egc, dc, &rec, sizeof(rec));
+ libxl__datacopier_prefixdata(egc, dc, toolstack_buf, toolstack_len);
+
+ padding_len = ROUNDUP(rec.length, REC_ALIGN_ORDER) - rec.length;
+ if (padding_len)
+ libxl__datacopier_prefixdata(egc, dc, zero_padding, padding_len);
+
+ free(toolstack_buf);
+ return;
+
+ err:
+ assert(ret);
+ free(toolstack_buf);
+ stream_failed(egc, stream, ret);
+}
+
+static void toolstack_record_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ if (dss->type == LIBXL_DOMAIN_TYPE_HVM)
+ write_emulator_record(egc, stream);
+ else
+ write_end_record(egc, stream);
+
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void write_emulator_record(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+ libxl__datacopier_state *dc = &stream->dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_rec_hdr rec = { REC_TYPE_EMULATOR_CONTEXT, 0 };
+ struct libxl_sr_emulator_hdr ehdr = { 0 };
+ struct stat st;
+ int ret = 0;
+ uint32_t qemu_state_len;
+
+ assert(dss->type == LIBXL_DOMAIN_TYPE_HVM);
+
+ /* Convenience aliases */
+ const char *const filename = dss->dm_savefile;
+ const uint32_t domid = dss->domid;
+
+ switch(libxl__device_model_version_running(gc, domid)) {
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
+ ehdr.id = EMULATOR_QEMU_TRADITIONAL;
+ break;
+
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
+ ehdr.id = EMULATOR_QEMU_UPSTREAM;
+ break;
+
+ default:
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ ret = libxl__domain_suspend_device_model(gc, dss);
+ if (ret)
+ goto err;
+
+ dc->readwhat = GCSPRINTF("qemu save file %s", filename);
+ dc->copywhat = "emulator record";
+ dc->writewhat = "save/migration stream";
+ dc->callback = emulator_body_done;
+
+ dc->readfd = open(filename, O_RDONLY);
+ if (dc->readfd < 0) {
+ LOGE(ERROR, "unable to open %s", dc->readwhat);
+ goto err;
+ }
+
+ if (fstat(dc->readfd, &st))
+ {
+ LOGE(ERROR, "unable to fstat %s", dc->readwhat);
+ goto err;
+ }
+
+ if (!S_ISREG(st.st_mode)) {
+ LOG(ERROR, "%s is not a plain file!", dc->readwhat);
+ goto err;
+ }
+
+ qemu_state_len = st.st_size;
+ rec.length = qemu_state_len + sizeof(ehdr);
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ libxl__datacopier_prefixdata(egc, dc, &rec, sizeof(rec));
+ libxl__datacopier_prefixdata(egc, dc, &ehdr, sizeof(ehdr));
+
+ stream->padding = ROUNDUP(qemu_state_len, REC_ALIGN_ORDER) -
qemu_state_len;
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void emulator_body_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ dc->readwhat = "";
+ dc->readfd = -1;
+
+ if (stream->padding) {
+ assert(stream->padding < (1U << REC_ALIGN_ORDER));
+
+ dc->copywhat = "emulator padding";
+ dc->writewhat = "save/migration stream";
+ dc->callback = emulator_padding_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ libxl__datacopier_prefixdata(egc, dc, zero_padding, stream->padding);
+ return;
+ }
+
+ emulator_padding_done(egc, dc, 0, 0);
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void emulator_padding_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ write_end_record(egc, stream);
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void write_end_record(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__datacopier_state *dc = &stream->dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_rec_hdr rec = { REC_TYPE_END, 0 };
+ int ret = 0;
+
+ dc->copywhat = "suspend footer";
+ dc->writewhat = "save/migration stream";
+ dc->callback = end_record_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ libxl__datacopier_prefixdata(egc, dc, &rec, sizeof(rec));
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void end_record_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ stream_success(egc, stream);
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
1.7.10.4
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