[libvirt] [PATCH 1/3] qemu: implement qemu's dump-guest-memory

[Wen Congyang]

dump-guest-memory is a new dump mechanism, and it can work when the
guest uses host devices. This patch adds a API to use this new
monitor command.

---
 src/qemu/qemu_monitor.c      |   38 ++++++++++++++++++++++++++++++++++++++
 src/qemu/qemu_monitor.h      |   12 ++++++++++++
 src/qemu/qemu_monitor_json.c |   34 ++++++++++++++++++++++++++++++++++
 src/qemu/qemu_monitor_json.h |    6 ++++++
 4 files changed, 90 insertions(+), 0 deletions(-)

diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index 2f66c46..a5d3eec 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -2018,6 +2018,44 @@ int qemuMonitorMigrateCancel(qemuMonitorPtr mon)
     return ret;
 }
 
+int qemuMonitorDumpToFd(qemuMonitorPtr mon,
+                        unsigned int flags,
+                        int fd,
+                        unsigned long long begin,
+                        unsigned long long length)
+{
+    int ret;
+    VIR_DEBUG("mon=%p fd=%d flags=%x begin=%llx length=%llx",
+              mon, fd, flags, begin, length);
+
+    if (!mon) {
+        qemuReportError(VIR_ERR_INVALID_ARG, "%s",
+                        _("monitor must not be NULL"));
+        return -1;
+    }
+
+    if (!mon->json) {
+        /* dump-guest-memory is supported after qemu-1.0, and we always use json
+         * if qemu's version is >= 0.15. So if we use text mode, the qemu is
+         * old, and it does not support dump-guest-memory.
+         */
+        qemuReportError(VIR_ERR_NO_SUPPORT, "%s",
+                        _("dump-guest-memory is not supported in text mode"));
+        return -1;
+    }
+
+    if (qemuMonitorSendFileHandle(mon, "dump", fd) < 0)
+        return -1;
+
+    ret = qemuMonitorJSONDump(mon, flags, "fd:dump", begin, length);
+
+    if (ret < 0) {
+        if (qemuMonitorCloseFileHandle(mon, "dump") < 0)
+            VIR_WARN("failed to close dumping handle");
+    }
+
+    return ret;
+}
 
 int qemuMonitorGraphicsRelocate(qemuMonitorPtr mon,
                                 int type,
diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
index f3cdcdd..7df52ad 100644
--- a/src/qemu/qemu_monitor.h
+++ b/src/qemu/qemu_monitor.h
@@ -379,6 +379,18 @@ int qemuMonitorMigrateToUnix(qemuMonitorPtr mon,
 
 int qemuMonitorMigrateCancel(qemuMonitorPtr mon);
 
+typedef enum {
+  QEMU_MONITOR_DUMP_HAVE_FILTER  = 1 << 0,
+  QEMU_MONITOR_DUMP_PAGING       = 1 << 1,
+  QEMU_MONITOR_DUMP_FLAGS_LAST
+} QEMU_MONITOR_DUMP;
+
+int qemuMonitorDumpToFd(qemuMonitorPtr mon,
+                        unsigned int flags,
+                        int fd,
+                        unsigned long long begin,
+                        unsigned long long length);
+
 int qemuMonitorGraphicsRelocate(qemuMonitorPtr mon,
                                 int type,
                                 const char *hostname,
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index eb58f13..b229a31 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -2461,6 +2461,40 @@ int qemuMonitorJSONMigrateCancel(qemuMonitorPtr mon)
     return ret;
 }
 
+int qemuMonitorJSONDump(qemuMonitorPtr mon,
+                        unsigned int flags,
+                        const char *protocol,
+                        unsigned long long begin,
+                        unsigned long long length)
+{
+    int ret;
+    virJSONValuePtr cmd = NULL;
+    virJSONValuePtr reply = NULL;
+
+    if (flags & QEMU_MONITOR_DUMP_HAVE_FILTER)
+        cmd = qemuMonitorJSONMakeCommand("dump-guest-memory",
+                                         "b:paging", flags & QEMU_MONITOR_DUMP_PAGING ? 1 : 0,
+                                         "s:protocol", protocol,
+                                         "U:begin", begin,
+                                         "U:length", length,
+                                         NULL);
+    else
+        cmd = qemuMonitorJSONMakeCommand("dump-guest-memory",
+                                         "b:paging", flags & QEMU_MONITOR_DUMP_PAGING ? 1 : 0,
+                                         "s:protocol", protocol,
+                                         NULL);
+    if (!cmd)
+        return -1;
+
+    ret = qemuMonitorJSONCommand(mon, cmd, &reply);
+
+    if (ret == 0)
+        ret = qemuMonitorJSONCheckError(cmd, reply);
+
+    virJSONValueFree(cmd);
+    virJSONValueFree(reply);
+    return ret;
+}
 
 int qemuMonitorJSONGraphicsRelocate(qemuMonitorPtr mon,
                                     int type,
diff --git a/src/qemu/qemu_monitor_json.h b/src/qemu/qemu_monitor_json.h
index aacbb5f..ccb2624 100644
--- a/src/qemu/qemu_monitor_json.h
+++ b/src/qemu/qemu_monitor_json.h
@@ -136,6 +136,12 @@ int qemuMonitorJSONMigrate(qemuMonitorPtr mon,
 
 int qemuMonitorJSONMigrateCancel(qemuMonitorPtr mon);
 
+int qemuMonitorJSONDump(qemuMonitorPtr mon,
+                        unsigned int flags,
+                        const char *protocol,
+                        unsigned long long begin,
+                        unsigned long long length);
+
 int qemuMonitorJSONGraphicsRelocate(qemuMonitorPtr mon,
                                     int type,
                                     const char *hostname,
-- 
1.7.1