[Qemu-devel] [PATCH 3/5] QAPI: Introduce memchar-write QMP command

[Lei Li]

Signed-off-by: Lei Li <address@hidden>
---
 hmp-commands.hx  |   23 ++++++++++++++++++
 hmp.c            |   19 +++++++++++++++
 hmp.h            |    1 +
 qapi-schema.json |   69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qemu-char.c      |   48 +++++++++++++++++++++++++++++++++++++
 qmp-commands.hx  |   39 ++++++++++++++++++++++++++++++
 6 files changed, 199 insertions(+), 0 deletions(-)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index ed67e99..fe11926 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -796,6 +796,29 @@ Inject an NMI on the given CPU (x86 only).
 ETEXI
 
     {
+        .name       = "memchar_write",
+        .args_type  = "chardev:s,size:i,data:s,format:s?,control:s?",
+        .params     = "chardev size data [format] [control]",
+        .help       = "Provide writing interface for CirMemCharDriver. Write"
+                      "'data' to it with size 'size'",
+        .mhandler.cmd = hmp_memchar_write,
+    },
+
+STEXI
address@hidden memchar_write @var{chardev} @var{size} @var{data} address@hidden 
address@hidden
address@hidden memchar_write
+Provide writing interface for CirMemCharDriver. Write @var{data}
+to cirmemchr char device with size @var{size}.
+
address@hidden is the format of the data write to CirMemCharDriver.
+Support 'utf8' and 'base64', by default is 'utf8'.
+
address@hidden is option('block', 'drop') for read and write command
+that specifies behavior when the queue is full/empty. By default is
+'drop'. Note that the 'block' option is not supported now.
+ETEXI
+
+    {
         .name       = "migrate",
         .args_type  = "detach:-d,blk:-b,inc:-i,uri:s",
         .params     = "[-d] [-b] [-i] uri",
diff --git a/hmp.c b/hmp.c
index ba6fbd3..97f5058 100644
--- a/hmp.c
+++ b/hmp.c
@@ -671,6 +671,25 @@ void hmp_pmemsave(Monitor *mon, const QDict *qdict)
     hmp_handle_error(mon, &errp);
 }
 
+void hmp_memchar_write(Monitor *mon, const QDict *qdict)
+{
+    uint32_t size = qdict_get_int(qdict, "size");
+    const char *chardev = qdict_get_str(qdict, "chardev");
+    const char *data = qdict_get_str(qdict, "data");
+    int val = qdict_get_try_bool(qdict, "base64", 0);
+    enum DataFormat format;
+    int con = qdict_get_try_bool(qdict, "block", 0);
+    enum CongestionControl control;
+    Error *errp = NULL;
+
+    format = val ? DATA_FORMAT_BASE64 : DATA_FORMAT_UTF8;
+    control = con ? CONGESTION_CONTROL_BLOCK : CONGESTION_CONTROL_DROP;
+    qmp_memchar_write(chardev, size, data, true, format,
+                      true, control, &errp);
+
+    hmp_handle_error(mon, &errp);
+}
+
 static void hmp_cont_cb(void *opaque, int err)
 {
     if (!err) {
diff --git a/hmp.h b/hmp.h
index 48b9c59..44b6463 100644
--- a/hmp.h
+++ b/hmp.h
@@ -43,6 +43,7 @@ void hmp_system_powerdown(Monitor *mon, const QDict *qdict);
 void hmp_cpu(Monitor *mon, const QDict *qdict);
 void hmp_memsave(Monitor *mon, const QDict *qdict);
 void hmp_pmemsave(Monitor *mon, const QDict *qdict);
+void hmp_memchar_write(Monitor *mon, const QDict *qdict);
 void hmp_cont(Monitor *mon, const QDict *qdict);
 void hmp_system_wakeup(Monitor *mon, const QDict *qdict);
 void hmp_inject_nmi(Monitor *mon, const QDict *qdict);
diff --git a/qapi-schema.json b/qapi-schema.json
index a9f465a..371239a 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -236,6 +236,75 @@
 { 'command': 'query-chardev', 'returns': ['ChardevInfo'] }
 
 ##
+# @DataFormat:
+#
+# An enumeration of data format write to or read from
+# memchardev. The default value would be utf8.
+#
+# @utf8: The data format is 'utf8'.
+#
+# @base64: The data format is 'base64'.
+#
+# Note: The data format start with 'utf8' and 'base64', will support
+#       other data format as well.
+#
+# Since: 1.3
+##
+{ 'enum': 'DataFormat'
+  'data': [ 'utf8', 'base64' ] }
+
+##
+# @CongestionControl
+#
+# An enumeration of options for the read and write command that
+# specifies behavior when the queue is full/empty. The default
+# option would be dropped.
+#
+# @drop: Would result in reads returning empty strings and writes
+#        dropping queued data.
+#
+# @block: Would make the session block until data was available
+#         or the queue had space available.
+#
+# Note: The option 'block' is not supported now due to the miss
+#       feature in qmp. Will add it later when we gain the necessary
+#       infrastructure enhancement.
+#
+# Since: 1.3
+##
+{'enum': 'CongestionControl'
+ 'data': [ 'drop', 'block' ] }
+
+##
+# @memchar-write:
+#
+# Provide writing interface for CirMemCharDriver. Write data to cirmemchar
+# char device.
+#
+# @chardev: the name of the cirmemchar char device.
+#
+# @size: the size to write in bytes.
+#
+# @data: the source data write to cirmemchar.
+#
+# @format: #optional the format of the data write to cirmemchar, by
+#          default is 'utf8'.
+#
+# @control: #optional options for read and write command that specifies
+#           behavior when the queue is full/empty.
+#
+# Returns: Nothing on success
+#          If @chardev is not a valid cirmemchr device, DeviceNotFound
+#          If an I/O error occurs while writing, IOError
+#
+# Since: 1.3
+##
+{ 'command': 'memchar-write',
+  'data': {'chardev': 'str', 'size': 'int', 'data': 'str',
+           '*format': 'DataFormat',
+           '*control': 'CongestionControl'} }
+
+##
 # @CommandInfo:
 #
 # Information about a QMP command
diff --git a/qemu-char.c b/qemu-char.c
index 6e84acc..be1d79a 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2700,6 +2700,54 @@ static CharDriverState *qemu_chr_open_cirmemchr(QemuOpts 
*opts)
     return chr;
 }
 
+void qmp_memchar_write(const char *chardev, int64_t size,
+                       const char *data, bool has_format,
+                       enum DataFormat format, bool has_control,
+                       enum CongestionControl control,
+                       Error **errp)
+{
+    CharDriverState *chr;
+    guchar *write_data;
+    int ret;
+    gsize write_count;
+
+    chr = qemu_chr_find(chardev);
+
+    if(!chr) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, chardev);
+        return;
+    }
+
+    /* XXX: For the sync command as 'block', waiting for the qmp
+ *      * to support necessary feature. Now just act as 'drop'. */
+    if (cirmem_chr_is_full(chr)) {
+        if (has_control && (control == CONGESTION_CONTROL_BLOCK)) {
+            g_free((char *)data);
+            return;
+        } else {
+            g_free((char *)data);
+            error_setg(errp, "Failed to write to memchr %s", chardev);
+            return;
+        }
+    }
+
+    write_count = (gsize)size;
+
+    if (has_format && (format == DATA_FORMAT_BASE64)) {
+        write_data = g_base64_decode(data, &write_count);
+    } else {
+        write_data = (uint8_t *)data;
+    }
+
+    ret = cirmem_chr_write(chr, write_data, write_count);
+    /* */
+    if (ret <= 0) {
+        error_setg(errp, "Failed to write to memchr %s", chardev);
+    }
+
+    g_free(write_data);
+}
+
 QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename)
 {
     char host[65], port[33], width[8], height[8];
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 6e21ddb..5a1b86b 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -466,6 +466,45 @@ Note: inject-nmi fails when the guest doesn't support 
injecting.
 EQMP
 
     {
+        .name       = "memchar-write",
+        .args_type  = "chardev:s,size:i,data:s,format:s?,control:s?",
+        .mhandler.cmd_new = qmp_marshal_input_memchar_write,
+    },
+
+SQMP
+memchar-write
+-------------
+
+Provide writing interface for CirMemCharDriver. Write data to cirmemchar
+char device.
+
+Arguments:
+
+- "chardev": the name of the char device, must be unique (json-string)
+- "size": the memory size, in bytes (json-int)
+- "data": the source data writed to cirmemchar (json-string)
+- "format": the data format write to CirMemCharDriver, default is
+            utf8. (json-string, optional)
+          - Possible values: "utf8", "base64"
+
+- "control": options for read and write command that specifies
+             behavior when the queue is full/empty, default is
+             drop. (json-string, optional)
+          - Possible values: "drop", "block"
+
+Example:
+
+-> { "execute": "memchar-write",
+                "arguments": { "chardev": foo,
+                               "size": 7,
+                               "data": "abcdefg",
+                               "format": "utf8",
+                               "control": "drop" } }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "xen-save-devices-state",
         .args_type  = "filename:F",
     .mhandler.cmd_new = qmp_marshal_input_xen_save_devices_state,
-- 
1.7.7.6