Merge remote-tracking branch 'remotes/qmp-unstable/queue/qmp' into staging

* remotes/qmp-unstable/queue/qmp:
  json-parser: drop superfluous assignment for token variable
  readline: Clear screen on form feed.
  monitor: Add delvm and loadvm argument completion
  monitor: Add host_net_remove arguments completion
  readline: Make completion strings always unique
  monitor: Add host_net_add device argument completion
  net: Export valid host network devices list
  monitor: Add migrate_set_capability completion
  monitor: Add watchdog_action argument completion
  monitor: Add ringbuf_write and ringbuf_read argument completion
  dump: simplify get_len_buf_out()
  dump: hoist lzo_init() from get_len_buf_out() to dump_init()
  dump: select header bitness based on ELF class, not ELF architecture
  dump: eliminate DumpState.page_size ("guest's page size")
  dump: eliminate DumpState.page_shift ("guest's page shift")
  dump: simplify write_start_flat_header()
  dump: fill in the flat header signature more pleasingly to the eye

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

11 files changed, 301 insertions, 116 deletions

diff --git a/dump.c b/dump.c
index e56b7cfc25..97d2c8dcef 100644
--- a/dump.c
+++ b/dump.c
@@ -90,8 +90,6 @@ typedef struct DumpState {
     uint8_t *note_buf;          /* buffer for notes */
     size_t note_buf_offset;     /* the writing place in note_buf */
     uint32_t nr_cpus;           /* number of guest's cpu */
-    size_t page_size;           /* guest's page size */
-    uint32_t page_shift;        /* guest's page shift */
     uint64_t max_mapnr;         /* the biggest guest's phys-mem's number */
     size_t len_dump_bitmap;     /* the size of the place used to store
                                    dump_bitmap in vmcore */
@@ -711,27 +709,25 @@ static int create_vmcore(DumpState *s)
 
 static int write_start_flat_header(int fd)
 {
-    uint8_t *buf;
-    MakedumpfileHeader mh;
+    MakedumpfileHeader *mh;
     int ret = 0;
 
-    memset(&mh, 0, sizeof(mh));
-    strncpy(mh.signature, MAKEDUMPFILE_SIGNATURE,
-            strlen(MAKEDUMPFILE_SIGNATURE));
+    QEMU_BUILD_BUG_ON(sizeof *mh > MAX_SIZE_MDF_HEADER);
+    mh = g_malloc0(MAX_SIZE_MDF_HEADER);
 
-    mh.type = cpu_to_be64(TYPE_FLAT_HEADER);
-    mh.version = cpu_to_be64(VERSION_FLAT_HEADER);
+    memcpy(mh->signature, MAKEDUMPFILE_SIGNATURE,
+           MIN(sizeof mh->signature, sizeof MAKEDUMPFILE_SIGNATURE));
 
-    buf = g_malloc0(MAX_SIZE_MDF_HEADER);
-    memcpy(buf, &mh, sizeof(mh));
+    mh->type = cpu_to_be64(TYPE_FLAT_HEADER);
+    mh->version = cpu_to_be64(VERSION_FLAT_HEADER);
 
     size_t written_size;
-    written_size = qemu_write_full(fd, buf, MAX_SIZE_MDF_HEADER);
+    written_size = qemu_write_full(fd, mh, MAX_SIZE_MDF_HEADER);
     if (written_size != MAX_SIZE_MDF_HEADER) {
         ret = -1;
     }
 
-    g_free(buf);
+    g_free(mh);
     return ret;
 }
 
@@ -808,7 +804,7 @@ static int create_header32(DumpState *s)
 
     strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
     dh->header_version = cpu_convert_to_target32(6, endian);
-    block_size = s->page_size;
+    block_size = TARGET_PAGE_SIZE;
     dh->block_size = cpu_convert_to_target32(block_size, endian);
     sub_hdr_size = sizeof(struct KdumpSubHeader32) + s->note_size;
     sub_hdr_size = DIV_ROUND_UP(sub_hdr_size, block_size);
@@ -915,7 +911,7 @@ static int create_header64(DumpState *s)
 
     strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
     dh->header_version = cpu_convert_to_target32(6, endian);
-    block_size = s->page_size;
+    block_size = TARGET_PAGE_SIZE;
     dh->block_size = cpu_convert_to_target32(block_size, endian);
     sub_hdr_size = sizeof(struct KdumpSubHeader64) + s->note_size;
     sub_hdr_size = DIV_ROUND_UP(sub_hdr_size, block_size);
@@ -1004,7 +1000,7 @@ out:
 
 static int write_dump_header(DumpState *s)
 {
-    if (s->dump_info.d_machine == EM_386) {
+    if (s->dump_info.d_class == ELFCLASS32) {
         return create_header32(s);
     } else {
         return create_header64(s);
@@ -1086,9 +1082,9 @@ static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr,
     if (!block) {
         block = QTAILQ_FIRST(&s->guest_phys_blocks.head);
         *blockptr = block;
-        assert(block->target_start % s->page_size == 0);
-        assert(block->target_end % s->page_size == 0);
-        *pfnptr = paddr_to_pfn(block->target_start, s->page_shift);
+        assert((block->target_start & ~TARGET_PAGE_MASK) == 0);
+        assert((block->target_end & ~TARGET_PAGE_MASK) == 0);
+        *pfnptr = paddr_to_pfn(block->target_start);
         if (bufptr) {
             *bufptr = block->host_addr;
         }
@@ -1096,10 +1092,10 @@ static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr,
     }
 
     *pfnptr = *pfnptr + 1;
-    addr = pfn_to_paddr(*pfnptr, s->page_shift);
+    addr = pfn_to_paddr(*pfnptr);
 
     if ((addr >= block->target_start) &&
-        (addr + s->page_size <= block->target_end)) {
+        (addr + TARGET_PAGE_SIZE <= block->target_end)) {
         buf = block->host_addr + (addr - block->target_start);
     } else {
         /* the next page is in the next block */
@@ -1108,9 +1104,9 @@ static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr,
         if (!block) {
             return false;
         }
-        assert(block->target_start % s->page_size == 0);
-        assert(block->target_end % s->page_size == 0);
-        *pfnptr = paddr_to_pfn(block->target_start, s->page_shift);
+        assert((block->target_start & ~TARGET_PAGE_MASK) == 0);
+        assert((block->target_end & ~TARGET_PAGE_MASK) == 0);
+        *pfnptr = paddr_to_pfn(block->target_start);
         buf = block->host_addr;
     }
 
@@ -1224,42 +1220,24 @@ static void free_data_cache(DataCache *data_cache)
 
 static size_t get_len_buf_out(size_t page_size, uint32_t flag_compress)
 {
-    size_t len_buf_out_zlib, len_buf_out_lzo, len_buf_out_snappy;
-    size_t len_buf_out;
-
-    /* init buf_out */
-    len_buf_out_zlib = len_buf_out_lzo = len_buf_out_snappy = 0;
-
-    /* buf size for zlib */
-    len_buf_out_zlib = compressBound(page_size);
-
-    /* buf size for lzo */
-#ifdef CONFIG_LZO
-    if (flag_compress & DUMP_DH_COMPRESSED_LZO) {
-        if (lzo_init() != LZO_E_OK) {
-            /* return 0 to indicate lzo is unavailable */
-            return 0;
-        }
-    }
-
-    /*
-     * LZO will expand incompressible data by a little amount. please check the
-     * following URL to see the expansion calculation:
-     * http://www.oberhumer.com/opensource/lzo/lzofaq.php
-     */
-    len_buf_out_lzo = page_size + page_size / 16 + 64 + 3;
-#endif
+    switch (flag_compress) {
+    case DUMP_DH_COMPRESSED_ZLIB:
+        return compressBound(page_size);
+
+    case DUMP_DH_COMPRESSED_LZO:
+        /*
+         * LZO will expand incompressible data by a little amount. Please check
+         * the following URL to see the expansion calculation:
+         * http://www.oberhumer.com/opensource/lzo/lzofaq.php
+         */
+        return page_size + page_size / 16 + 64 + 3;
 
 #ifdef CONFIG_SNAPPY
-    /* buf size for snappy */
-    len_buf_out_snappy = snappy_max_compressed_length(page_size);
+    case DUMP_DH_COMPRESSED_SNAPPY:
+        return snappy_max_compressed_length(page_size);
 #endif
-
-    /* get the biggest that can store all kinds of compressed page */
-    len_buf_out = MAX(len_buf_out_zlib,
-                      MAX(len_buf_out_lzo, len_buf_out_snappy));
-
-    return len_buf_out;
+    }
+    return 0;
 }
 
 /*
@@ -1294,11 +1272,8 @@ static int write_dump_pages(DumpState *s)
     prepare_data_cache(&page_data, s, offset_data);
 
     /* prepare buffer to store compressed data */
-    len_buf_out = get_len_buf_out(s->page_size, s->flag_compress);
-    if (len_buf_out == 0) {
-        dump_error(s, "dump: failed to get length of output buffer.\n");
-        goto out;
-    }
+    len_buf_out = get_len_buf_out(TARGET_PAGE_SIZE, s->flag_compress);
+    assert(len_buf_out != 0);
 
 #ifdef CONFIG_LZO
     wrkmem = g_malloc(LZO1X_1_MEM_COMPRESS);
@@ -1310,19 +1285,19 @@ static int write_dump_pages(DumpState *s)
      * init zero page's page_desc and page_data, because every zero page
      * uses the same page_data
      */
-    pd_zero.size = cpu_convert_to_target32(s->page_size, endian);
+    pd_zero.size = cpu_convert_to_target32(TARGET_PAGE_SIZE, endian);
     pd_zero.flags = cpu_convert_to_target32(0, endian);
     pd_zero.offset = cpu_convert_to_target64(offset_data, endian);
     pd_zero.page_flags = cpu_convert_to_target64(0, endian);
-    buf = g_malloc0(s->page_size);
-    ret = write_cache(&page_data, buf, s->page_size, false);
+    buf = g_malloc0(TARGET_PAGE_SIZE);
+    ret = write_cache(&page_data, buf, TARGET_PAGE_SIZE, false);
     g_free(buf);
     if (ret < 0) {
         dump_error(s, "dump: failed to write page data(zero page).\n");
         goto out;
     }
 
-    offset_data += s->page_size;
+    offset_data += TARGET_PAGE_SIZE;
 
     /*
      * dump memory to vmcore page by page. zero page will all be resided in the
@@ -1330,7 +1305,7 @@ static int write_dump_pages(DumpState *s)
      */
     while (get_next_page(&block_iter, &pfn_iter, &buf, s)) {
         /* check zero page */
-        if (is_zero_page(buf, s->page_size)) {
+        if (is_zero_page(buf, TARGET_PAGE_SIZE)) {
             ret = write_cache(&page_desc, &pd_zero, sizeof(PageDescriptor),
                               false);
             if (ret < 0) {
@@ -1351,8 +1326,9 @@ static int write_dump_pages(DumpState *s)
              */
              size_out = len_buf_out;
              if ((s->flag_compress & DUMP_DH_COMPRESSED_ZLIB) &&
-                    (compress2(buf_out, (uLongf *)&size_out, buf, s->page_size,
-                    Z_BEST_SPEED) == Z_OK) && (size_out < s->page_size)) {
+                 (compress2(buf_out, (uLongf *)&size_out, buf,
+                            TARGET_PAGE_SIZE, Z_BEST_SPEED) == Z_OK) &&
+                 (size_out < TARGET_PAGE_SIZE)) {
                 pd.flags = cpu_convert_to_target32(DUMP_DH_COMPRESSED_ZLIB,
                                                    endian);
                 pd.size  = cpu_convert_to_target32(size_out, endian);
@@ -1364,9 +1340,9 @@ static int write_dump_pages(DumpState *s)
                 }
 #ifdef CONFIG_LZO
             } else if ((s->flag_compress & DUMP_DH_COMPRESSED_LZO) &&
-                    (lzo1x_1_compress(buf, s->page_size, buf_out,
+                    (lzo1x_1_compress(buf, TARGET_PAGE_SIZE, buf_out,
                     (lzo_uint *)&size_out, wrkmem) == LZO_E_OK) &&
-                    (size_out < s->page_size)) {
+                    (size_out < TARGET_PAGE_SIZE)) {
                 pd.flags = cpu_convert_to_target32(DUMP_DH_COMPRESSED_LZO,
                                                    endian);
                 pd.size  = cpu_convert_to_target32(size_out, endian);
@@ -1379,9 +1355,9 @@ static int write_dump_pages(DumpState *s)
 #endif
 #ifdef CONFIG_SNAPPY
             } else if ((s->flag_compress & DUMP_DH_COMPRESSED_SNAPPY) &&
-                    (snappy_compress((char *)buf, s->page_size,
+                    (snappy_compress((char *)buf, TARGET_PAGE_SIZE,
                     (char *)buf_out, &size_out) == SNAPPY_OK) &&
-                    (size_out < s->page_size)) {
+                    (size_out < TARGET_PAGE_SIZE)) {
                 pd.flags = cpu_convert_to_target32(
                                         DUMP_DH_COMPRESSED_SNAPPY, endian);
                 pd.size  = cpu_convert_to_target32(size_out, endian);
@@ -1395,13 +1371,13 @@ static int write_dump_pages(DumpState *s)
             } else {
                 /*
                  * fall back to save in plaintext, size_out should be
-                 * assigned to s->page_size
+                 * assigned TARGET_PAGE_SIZE
                  */
                 pd.flags = cpu_convert_to_target32(0, endian);
-                size_out = s->page_size;
+                size_out = TARGET_PAGE_SIZE;
                 pd.size = cpu_convert_to_target32(size_out, endian);
 
-                ret = write_cache(&page_data, buf, s->page_size, false);
+                ret = write_cache(&page_data, buf, TARGET_PAGE_SIZE, false);
                 if (ret < 0) {
                     dump_error(s, "dump: failed to write page data.\n");
                     goto out;
@@ -1536,7 +1512,7 @@ static void get_max_mapnr(DumpState *s)
     GuestPhysBlock *last_block;
 
     last_block = QTAILQ_LAST(&s->guest_phys_blocks.head, GuestPhysBlockHead);
-    s->max_mapnr = paddr_to_pfn(last_block->target_end, s->page_shift);
+    s->max_mapnr = paddr_to_pfn(last_block->target_end);
 }
 
 static int dump_init(DumpState *s, int fd, bool has_format,
@@ -1613,14 +1589,12 @@ static int dump_init(DumpState *s, int fd, bool has_format,
     }
 
     s->nr_cpus = nr_cpus;
-    s->page_size = TARGET_PAGE_SIZE;
-    s->page_shift = ffs(s->page_size) - 1;
 
     get_max_mapnr(s);
 
     uint64_t tmp;
-    tmp = DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT), s->page_size);
-    s->len_dump_bitmap = tmp * s->page_size;
+    tmp = DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT), TARGET_PAGE_SIZE);
+    s->len_dump_bitmap = tmp * TARGET_PAGE_SIZE;
 
     /* init for kdump-compressed format */
     if (has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) {
@@ -1630,6 +1604,12 @@ static int dump_init(DumpState *s, int fd, bool has_format,
             break;
 
         case DUMP_GUEST_MEMORY_FORMAT_KDUMP_LZO:
+#ifdef CONFIG_LZO
+            if (lzo_init() != LZO_E_OK) {
+                error_setg(errp, "failed to initialize the LZO library");
+                goto cleanup;
+            }
+#endif
             s->flag_compress = DUMP_DH_COMPRESSED_LZO;
             break;
 
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 2e462c04aa..5f1a677b85 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -335,6 +335,7 @@ ETEXI
         .params     = "tag|id",
         .help       = "restore a VM snapshot from its tag or id",
         .mhandler.cmd = do_loadvm,
+        .command_completion = loadvm_completion,
     },
 
 STEXI
@@ -350,6 +351,7 @@ ETEXI
         .params     = "tag|id",
         .help       = "delete a VM snapshot from its tag or id",
         .mhandler.cmd = do_delvm,
+        .command_completion = delvm_completion,
     },
 
 STEXI
@@ -852,6 +854,7 @@ ETEXI
         .params     = "device data",
         .help       = "Write to a ring buffer character device",
         .mhandler.cmd = hmp_ringbuf_write,
+        .command_completion = ringbuf_write_completion,
     },
 
 STEXI
@@ -868,6 +871,7 @@ ETEXI
         .params     = "device size",
         .help       = "Read from a ring buffer character device",
         .mhandler.cmd = hmp_ringbuf_read,
+        .command_completion = ringbuf_write_completion,
     },
 
 STEXI
@@ -973,6 +977,7 @@ ETEXI
         .params     = "capability state",
         .help       = "Enable/Disable the usage of a capability for migration",
         .mhandler.cmd = hmp_migrate_set_capability,
+        .command_completion = migrate_set_capability_completion,
     },
 
 STEXI
@@ -1206,9 +1211,10 @@ ETEXI
     {
         .name       = "host_net_add",
         .args_type  = "device:s,opts:s?",
-        .params     = "tap|user|socket|vde|netmap|dump [options]",
+        .params     = "tap|user|socket|vde|netmap|bridge|dump [options]",
         .help       = "add host VLAN client",
         .mhandler.cmd = net_host_device_add,
+        .command_completion = host_net_add_completion,
     },
 
 STEXI
@@ -1223,6 +1229,7 @@ ETEXI
         .params     = "vlan_id name",
         .help       = "remove host VLAN client",
         .mhandler.cmd = net_host_device_remove,
+        .command_completion = host_net_remove_completion,
     },
 
 STEXI
@@ -1357,6 +1364,7 @@ ETEXI
         .params     = "[reset|shutdown|poweroff|pause|debug|none]",
         .help       = "change watchdog action",
         .mhandler.cmd = do_watchdog_action,
+        .command_completion = watchdog_action_completion,
     },
 
 STEXI
diff --git a/hmp.h b/hmp.h
index aba59e95f0..2d9b0a2b0b 100644
--- a/hmp.h
+++ b/hmp.h
@@ -103,5 +103,16 @@ void chardev_add_completion(ReadLineState *rs, int nb_args, const char *str);
 void set_link_completion(ReadLineState *rs, int nb_args, const char *str);
 void netdev_add_completion(ReadLineState *rs, int nb_args, const char *str);
 void netdev_del_completion(ReadLineState *rs, int nb_args, const char *str);
+void ringbuf_write_completion(ReadLineState *rs, int nb_args, const char *str);
+void ringbuf_read_completion(ReadLineState *rs, int nb_args, const char *str);
+void watchdog_action_completion(ReadLineState *rs, int nb_args,
+                                const char *str);
+void migrate_set_capability_completion(ReadLineState *rs, int nb_args,
+                                       const char *str);
+void host_net_add_completion(ReadLineState *rs, int nb_args, const char *str);
+void host_net_remove_completion(ReadLineState *rs, int nb_args,
+                                const char *str);
+void delvm_completion(ReadLineState *rs, int nb_args, const char *str);
+void loadvm_completion(ReadLineState *rs, int nb_args, const char *str);
 
 #endif
diff --git a/include/net/net.h b/include/net/net.h
index 8166345a13..8b189da5ee 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -177,6 +177,7 @@ struct NICInfo {
 extern int nb_nics;
 extern NICInfo nd_table[MAX_NICS];
 extern int default_net;
+extern const char *host_net_devices[];
 
 /* from net.c */
 extern const char *legacy_tftp_prefix;
diff --git a/include/sysemu/char.h b/include/sysemu/char.h
index b81a6ff185..7f5eeb38b0 100644
--- a/include/sysemu/char.h
+++ b/include/sysemu/char.h
@@ -286,9 +286,8 @@ void qemu_chr_add_handlers(CharDriverState *s,
 void qemu_chr_be_generic_open(CharDriverState *s);
 void qemu_chr_accept_input(CharDriverState *s);
 int qemu_chr_add_client(CharDriverState *s, int fd);
-void qemu_chr_info_print(Monitor *mon, const QObject *ret_data);
-void qemu_chr_info(Monitor *mon, QObject **ret_data);
 CharDriverState *qemu_chr_find(const char *name);
+bool chr_is_ringbuf(const CharDriverState *chr);
 
 QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename);
 
diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h
index efab7a32f3..12af557b55 100644
--- a/include/sysemu/dump.h
+++ b/include/sysemu/dump.h
@@ -22,10 +22,10 @@
 
 #define ARCH_PFN_OFFSET             (0)
 
-#define paddr_to_pfn(X, page_shift) \
-    (((unsigned long long)(X) >> (page_shift)) - ARCH_PFN_OFFSET)
-#define pfn_to_paddr(X, page_shift) \
-    (((unsigned long long)(X) + ARCH_PFN_OFFSET) << (page_shift))
+#define paddr_to_pfn(X) \
+    (((unsigned long long)(X) >> TARGET_PAGE_BITS) - ARCH_PFN_OFFSET)
+#define pfn_to_paddr(X) \
+    (((unsigned long long)(X) + ARCH_PFN_OFFSET) << TARGET_PAGE_BITS)
 
 /*
  * flag for compressed format
diff --git a/monitor.c b/monitor.c
index 0565816910..ee9390f659 100644
--- a/monitor.c
+++ b/monitor.c
@@ -70,6 +70,7 @@
 #include "qmp-commands.h"
 #include "hmp.h"
 #include "qemu/thread.h"
+#include "block/qapi.h"
 
 /* for pic/irq_info */
 #if defined(TARGET_SPARC)
@@ -4412,6 +4413,45 @@ void chardev_remove_completion(ReadLineState *rs, int nb_args, const char *str)
     qapi_free_ChardevInfoList(start);
 }
 
+static void ringbuf_completion(ReadLineState *rs, const char *str)
+{
+    size_t len;
+    ChardevInfoList *list, *start;
+
+    len = strlen(str);
+    readline_set_completion_index(rs, len);
+
+    start = list = qmp_query_chardev(NULL);
+    while (list) {
+        ChardevInfo *chr_info = list->value;
+
+        if (!strncmp(chr_info->label, str, len)) {
+            CharDriverState *chr = qemu_chr_find(chr_info->label);
+            if (chr && chr_is_ringbuf(chr)) {
+                readline_add_completion(rs, chr_info->label);
+            }
+        }
+        list = list->next;
+    }
+    qapi_free_ChardevInfoList(start);
+}
+
+void ringbuf_read_completion(ReadLineState *rs, int nb_args, const char *str)
+{
+    if (nb_args != 2) {
+        return;
+    }
+    ringbuf_completion(rs, str);
+}
+
+void ringbuf_write_completion(ReadLineState *rs, int nb_args, const char *str)
+{
+    if (nb_args != 2) {
+        return;
+    }
+    ringbuf_completion(rs, str);
+}
+
 void device_del_completion(ReadLineState *rs, int nb_args, const char *str)
 {
     size_t len;
@@ -4520,6 +4560,142 @@ void netdev_del_completion(ReadLineState *rs, int nb_args, const char *str)
     }
 }
 
+void watchdog_action_completion(ReadLineState *rs, int nb_args, const char *str)
+{
+    if (nb_args != 2) {
+        return;
+    }
+    readline_set_completion_index(rs, strlen(str));
+    add_completion_option(rs, str, "reset");
+    add_completion_option(rs, str, "shutdown");
+    add_completion_option(rs, str, "poweroff");
+    add_completion_option(rs, str, "pause");
+    add_completion_option(rs, str, "debug");
+    add_completion_option(rs, str, "none");
+}
+
+void migrate_set_capability_completion(ReadLineState *rs, int nb_args,
+                                       const char *str)
+{
+    size_t len;
+
+    len = strlen(str);
+    readline_set_completion_index(rs, len);
+    if (nb_args == 2) {
+        int i;
+        for (i = 0; i < MIGRATION_CAPABILITY_MAX; i++) {
+            const char *name = MigrationCapability_lookup[i];
+            if (!strncmp(str, name, len)) {
+                readline_add_completion(rs, name);
+            }
+        }
+    } else if (nb_args == 3) {
+        add_completion_option(rs, str, "on");
+        add_completion_option(rs, str, "off");
+    }
+}
+
+void host_net_add_completion(ReadLineState *rs, int nb_args, const char *str)
+{
+    int i;
+    size_t len;
+    if (nb_args != 2) {
+        return;
+    }
+    len = strlen(str);
+    readline_set_completion_index(rs, len);
+    for (i = 0; host_net_devices[i]; i++) {
+        if (!strncmp(host_net_devices[i], str, len)) {
+            readline_add_completion(rs, host_net_devices[i]);
+        }
+    }
+}
+
+void host_net_remove_completion(ReadLineState *rs, int nb_args, const char *str)
+{
+    NetClientState *ncs[255];
+    int count, i, len;
+
+    len = strlen(str);
+    readline_set_completion_index(rs, len);
+    if (nb_args == 2) {
+        count = qemu_find_net_clients_except(NULL, ncs,
+                                             NET_CLIENT_OPTIONS_KIND_NONE, 255);
+        for (i = 0; i < count; i++) {
+            int id;
+            char name[16];
+
+            if (net_hub_id_for_client(ncs[i], &id)) {
+                continue;
+            }
+            snprintf(name, sizeof(name), "%d", id);
+            if (!strncmp(str, name, len)) {
+                readline_add_completion(rs, name);
+            }
+        }
+        return;
+    } else if (nb_args == 3) {
+        count = qemu_find_net_clients_except(NULL, ncs,
+                                             NET_CLIENT_OPTIONS_KIND_NIC, 255);
+        for (i = 0; i < count; i++) {
+            const char *name;
+
+            name = ncs[i]->name;
+            if (!strncmp(str, name, len)) {
+                readline_add_completion(rs, name);
+            }
+        }
+        return;
+    }
+}
+
+static void vm_completion(ReadLineState *rs, const char *str)
+{
+    size_t len;
+    BlockDriverState *bs = NULL;
+
+    len = strlen(str);
+    readline_set_completion_index(rs, len);
+    while ((bs = bdrv_next(bs))) {
+        SnapshotInfoList *snapshots, *snapshot;
+
+        if (!bdrv_can_snapshot(bs)) {
+            continue;
+        }
+        if (bdrv_query_snapshot_info_list(bs, &snapshots, NULL)) {
+            continue;
+        }
+        snapshot = snapshots;
+        while (snapshot) {
+            char *completion = snapshot->value->name;
+            if (!strncmp(str, completion, len)) {
+                readline_add_completion(rs, completion);
+            }
+            completion = snapshot->value->id;
+            if (!strncmp(str, completion, len)) {
+                readline_add_completion(rs, completion);
+            }
+            snapshot = snapshot->next;
+        }
+        qapi_free_SnapshotInfoList(snapshots);
+    }
+
+}
+
+void delvm_completion(ReadLineState *rs, int nb_args, const char *str)
+{
+    if (nb_args == 2) {
+        vm_completion(rs, str);
+    }
+}
+
+void loadvm_completion(ReadLineState *rs, int nb_args, const char *str)
+{
+    if (nb_args == 2) {
+        vm_completion(rs, str);
+    }
+}
+
 static void monitor_find_completion_by_table(Monitor *mon,
                                              const mon_cmd_t *cmd_table,
                                              char **args,
diff --git a/net/net.c b/net/net.c
index 0ff2e40f35..6344160403 100644
--- a/net/net.c
+++ b/net/net.c
@@ -49,6 +49,22 @@
 
 static QTAILQ_HEAD(, NetClientState) net_clients;
 
+const char *host_net_devices[] = {
+    "tap",
+    "socket",
+    "dump",
+#ifdef CONFIG_NET_BRIDGE
+    "bridge",
+#endif
+#ifdef CONFIG_SLIRP
+    "user",
+#endif
+#ifdef CONFIG_VDE
+    "vde",
+#endif
+    NULL,
+};
+
 int default_net = 1;
 
 /***********************************************************/
@@ -897,21 +913,11 @@ int net_client_init(QemuOpts *opts, int is_netdev, Error **errp)
 static int net_host_check_device(const char *device)
 {
     int i;
-    const char *valid_param_list[] = { "tap", "socket", "dump"
-#ifdef CONFIG_NET_BRIDGE
-                                       , "bridge"
-#endif
-#ifdef CONFIG_SLIRP
-                                       ,"user"
-#endif
-#ifdef CONFIG_VDE
-                                       ,"vde"
-#endif
-    };
-    for (i = 0; i < ARRAY_SIZE(valid_param_list); i++) {
-        if (!strncmp(valid_param_list[i], device,
-                     strlen(valid_param_list[i])))
+    for (i = 0; host_net_devices[i]; i++) {
+        if (!strncmp(host_net_devices[i], device,
+                     strlen(host_net_devices[i]))) {
             return 1;
+        }
     }
 
     return 0;
diff --git a/qemu-char.c b/qemu-char.c
index 17b476edf0..4c04bbc24e 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2849,7 +2849,7 @@ fail:
     return NULL;
 }
 
-static bool chr_is_ringbuf(const CharDriverState *chr)
+bool chr_is_ringbuf(const CharDriverState *chr)
 {
     return chr->chr_write == ringbuf_chr_write;
 }
diff --git a/qobject/json-parser.c b/qobject/json-parser.c
index e46c26448e..4288267bd3 100644
--- a/qobject/json-parser.c
+++ b/qobject/json-parser.c
@@ -423,7 +423,6 @@ static QObject *parse_object(JSONParserContext *ctxt, va_list *ap)
     if (!token_is_operator(token, '{')) {
         goto out;
     }
-    token = NULL;
 
     dict = qdict_new();
 
@@ -449,7 +448,6 @@ static QObject *parse_object(JSONParserContext *ctxt, va_list *ap)
                 parse_error(ctxt, token, "expected separator in dict");
                 goto out;
             }
-            token = NULL;
 
             if (parse_pair(ctxt, dict, ap) == -1) {
                 goto out;
@@ -461,10 +459,8 @@ static QObject *parse_object(JSONParserContext *ctxt, va_list *ap)
                 goto out;
             }
         }
-        token = NULL;
     } else {
-        token = parser_context_pop_token(ctxt);
-        token = NULL;
+        (void)parser_context_pop_token(ctxt);
     }
 
     return QOBJECT(dict);
@@ -487,10 +483,8 @@ static QObject *parse_array(JSONParserContext *ctxt, va_list *ap)
     }
 
     if (!token_is_operator(token, '[')) {
-        token = NULL;
         goto out;
     }
-    token = NULL;
 
     list = qlist_new();
 
@@ -523,8 +517,6 @@ static QObject *parse_array(JSONParserContext *ctxt, va_list *ap)
                 goto out;
             }
 
-            token = NULL;
-
             obj = parse_value(ctxt, ap);
             if (obj == NULL) {
                 parse_error(ctxt, token, "expecting value");
@@ -539,11 +531,8 @@ static QObject *parse_array(JSONParserContext *ctxt, va_list *ap)
                 goto out;
             }
         }
-
-        token = NULL;
     } else {
-        token = parser_context_pop_token(ctxt);
-        token = NULL;
+        (void)parser_context_pop_token(ctxt);
     }
 
     return QOBJECT(list);
diff --git a/util/readline.c b/util/readline.c
index 8baec55509..cc1302ac0a 100644
--- a/util/readline.c
+++ b/util/readline.c
@@ -263,6 +263,12 @@ static void readline_hist_add(ReadLineState *rs, const char *cmdline)
 void readline_add_completion(ReadLineState *rs, const char *str)
 {
     if (rs->nb_completions < READLINE_MAX_COMPLETIONS) {
+        int i;
+        for (i = 0; i < rs->nb_completions; i++) {
+            if (!strcmp(rs->completions[i], str)) {
+                return;
+            }
+        }
         rs->completions[rs->nb_completions++] = g_strdup(str);
     }
 }
@@ -345,6 +351,12 @@ static void readline_completion(ReadLineState *rs)
     }
 }
 
+static void readline_clear_screen(ReadLineState *rs)
+{
+    rs->printf_func(rs->opaque, "\033[2J\033[1;1H");
+    readline_show_prompt(rs);
+}
+
 /* return true if command handled */
 void readline_handle_byte(ReadLineState *rs, int ch)
 {
@@ -363,6 +375,9 @@ void readline_handle_byte(ReadLineState *rs, int ch)
         case 9:
             readline_completion(rs);
             break;
+        case 12:
+            readline_clear_screen(rs);
+            break;
         case 10:
         case 13:
             rs->cmd_buf[rs->cmd_buf_size] = '\0';