Merge remote-tracking branch 'luiz/queue/qmp' into staging

# By Lei Li (3) and others
# Via Luiz Capitulino
* luiz/queue/qmp:
  QAPI: Introduce memchar-read QMP command
  QAPI: Introduce memchar-write QMP command
  qemu-char: Add new char backend CirMemCharDriver
  docs: document virtio-balloon stats
  balloon: re-enable balloon stats
  balloon: drop old stats code & API
  block: Monitor command commit neglects to report some errors

qemu-char.c

@@ -98,6 +98,7 @@
 #include "ui/qemu-spice.h"
 
 #define READ_BUF_LEN 4096
+#define CBUFF_SIZE 65536
 
 /***********************************************************/
 /* character device */
@@ -2643,6 +2644,199 @@ size_t qemu_chr_mem_osize(const CharDriverState *chr)
     return d->outbuf_size;
 }
 
+/*********************************************************/
+/*CircularMemory chardev*/
+
+typedef struct {
+    size_t size;
+    size_t prod;
+    size_t cons;
+    uint8_t *cbuf;
+} CirMemCharDriver;
+
+static bool cirmem_chr_is_empty(const CharDriverState *chr)
+{
+    const CirMemCharDriver *d = chr->opaque;
+
+    return d->cons == d->prod;
+}
+
+static size_t qemu_chr_cirmem_count(const CharDriverState *chr)
+{
+    const CirMemCharDriver *d = chr->opaque;
+
+    return (d->prod - d->cons);
+}
+
+static int cirmem_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
+{
+    CirMemCharDriver *d = chr->opaque;
+    int i;
+
+    if (!buf || (len < 0)) {
+        return -1;
+    }
+
+    for (i = 0; i < len; i++ ) {
+        /* Avoid writing the IAC information to the queue. */
+        if ((unsigned char)buf[i] == IAC) {
+            continue;
+        }
+
+        d->cbuf[d->prod++ % d->size] = buf[i];
+        if ((d->prod - d->cons) > d->size) {
+            d->cons = d->prod - d->size;
+        }
+    }
+
+    return 0;
+}
+
+static int cirmem_chr_read(CharDriverState *chr, uint8_t *buf, int len)
+{
+    CirMemCharDriver *d = chr->opaque;
+    int i;
+
+    for (i = 0; i < len && !cirmem_chr_is_empty(chr); i++) {
+        buf[i] = d->cbuf[d->cons++ % d->size];
+    }
+
+    return i;
+}
+
+static void cirmem_chr_close(struct CharDriverState *chr)
+{
+    CirMemCharDriver *d = chr->opaque;
+
+    g_free(d->cbuf);
+    g_free(d);
+    chr->opaque = NULL;
+}
+
+static CharDriverState *qemu_chr_open_cirmemchr(QemuOpts *opts)
+{
+    CharDriverState *chr;
+    CirMemCharDriver *d;
+
+    chr = g_malloc0(sizeof(CharDriverState));
+    d = g_malloc(sizeof(*d));
+
+    d->size = qemu_opt_get_number(opts, "maxcapacity", 0);
+    if (d->size == 0) {
+        d->size = CBUFF_SIZE;
+    }
+
+    /* The size must be power of 2 */
+    if (d->size & (d->size - 1)) {
+        fprintf(stderr, "chardev: size of memory device must be power of 2\n");
+        goto fail;
+    }
+
+    d->prod = 0;
+    d->cons = 0;
+    d->cbuf = g_malloc0(d->size);
+
+    chr->opaque = d;
+    chr->chr_write = cirmem_chr_write;
+    chr->chr_close = cirmem_chr_close;
+
+    return chr;
+
+fail:
+    g_free(d);
+    g_free(chr);
+    return NULL;
+}
+
+static bool qemu_is_chr(const CharDriverState *chr, const char *filename)
+{
+    return strcmp(chr->filename, filename);
+}
+
+void qmp_memchar_write(const char *device, int64_t size,
+                       const char *data, bool has_format,
+                       enum DataFormat format,
+                       Error **errp)
+{
+    CharDriverState *chr;
+    guchar *write_data;
+    int ret;
+    gsize write_count;
+
+    chr = qemu_chr_find(device);
+    if (!chr) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return;
+    }
+
+    if (qemu_is_chr(chr, "memory")) {
+        error_setg(errp,"%s is not memory char device", device);
+        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 device %s", device);
+        return;
+    }
+}
+
+MemCharRead *qmp_memchar_read(const char *device, int64_t size,
+                              bool has_format, enum DataFormat format,
+                              Error **errp)
+{
+    CharDriverState *chr;
+    guchar *read_data;
+    MemCharRead *meminfo;
+    size_t count;
+
+    chr = qemu_chr_find(device);
+    if (!chr) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return NULL;
+    }
+
+    if (qemu_is_chr(chr, "memory")) {
+        error_setg(errp,"%s is not memory char device", device);
+        return NULL;
+    }
+
+    if (size <= 0) {
+        error_setg(errp, "size must be greater than zero");
+        return NULL;
+    }
+
+    meminfo = g_malloc0(sizeof(MemCharRead));
+
+    count = qemu_chr_cirmem_count(chr);
+    if (count == 0) {
+        meminfo->data = g_strdup("");
+        return meminfo;
+    }
+
+    size = size > count ? count : size;
+    read_data = g_malloc0(size + 1);
+
+    meminfo->count = cirmem_chr_read(chr, read_data, size);
+
+    if (has_format && (format == DATA_FORMAT_BASE64)) {
+        meminfo->data = g_base64_encode(read_data, (size_t)meminfo->count);
+    } else {
+        meminfo->data = (char *)read_data;
+    }
+
+    return meminfo;
+}
+
 QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename)
 {
     char host[65], port[33], width[8], height[8];
@@ -2697,6 +2891,11 @@ QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename)
         qemu_opt_set(opts, "path", filename);
         return opts;
     }
+    if (strstart(filename, "memory", &p)) {
+        qemu_opt_set(opts, "backend", "memory");
+        qemu_opt_set(opts, "maxcapacity", p);
+        return opts;
+    }
     if (strstart(filename, "file:", &p)) {
         qemu_opt_set(opts, "backend", "file");
         qemu_opt_set(opts, "path", p);
@@ -2796,6 +2995,7 @@ static const struct {
     { .name = "udp",       .open = qemu_chr_open_udp },
     { .name = "msmouse",   .open = qemu_chr_open_msmouse },
     { .name = "vc",        .open = text_console_init },
+    { .name = "memory",    .open = qemu_chr_open_cirmemchr },
 #ifdef _WIN32
     { .name = "file",      .open = qemu_chr_open_win_file_out },
     { .name = "pipe",      .open = qemu_chr_open_win_pipe },
@@ -3055,6 +3255,9 @@ QemuOptsList qemu_chardev_opts = {
         },{
             .name = "debug",
             .type = QEMU_OPT_NUMBER,
+        },{
+            .name = "maxcapacity",
+            .type = QEMU_OPT_NUMBER,
         },
         { /* end of list */ }
     },