Merge remote-tracking branch 'quintela/migration.next' into staging

# By Orit Wasserman
# Via Juan Quintela
* quintela/migration.next:
  Fix error message in migrate_set_capability HMP command
  Allow XBZRLE decoding without enabling the capability
  Fix example for query-migrate-capabilities
  Add XBZRLE testing
  Move XBZRLE encoding code to a separate file to allow testing

8 files changed, 376 insertions, 168 deletions

diff --git a/Makefile.objs b/Makefile.objs
index 68eb0cef1a..21e9c911f5 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -59,7 +59,7 @@ common-obj-$(CONFIG_LINUX) += fsdev/
 common-obj-y += migration.o migration-tcp.o
 common-obj-y += qemu-char.o #aio.o
 common-obj-y += block-migration.o
-common-obj-y += page_cache.o
+common-obj-y += page_cache.o xbzrle.o
 
 common-obj-$(CONFIG_POSIX) += migration-exec.o migration-unix.o migration-fd.o
 
diff --git a/arch_init.c b/arch_init.c
index dada6ded1a..8da868b988 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -851,9 +851,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
 
             qemu_get_buffer(f, host, TARGET_PAGE_SIZE);
         } else if (flags & RAM_SAVE_FLAG_XBZRLE) {
-            if (!migrate_use_xbzrle()) {
-                return -EINVAL;
-            }
             void *host = host_from_stream_offset(f, addr, flags);
             if (!host) {
                 return -EINVAL;
diff --git a/hmp.c b/hmp.c
index 249b89b7e3..1689e6f1fd 100644
--- a/hmp.c
+++ b/hmp.c
@@ -892,7 +892,7 @@ void hmp_migrate_set_capability(Monitor *mon, const QDict *qdict)
     qapi_free_MigrationCapabilityStatusList(caps);
 
     if (err) {
-        monitor_printf(mon, "migrate_set_parameter: %s\n",
+        monitor_printf(mon, "migrate_set_capability: %s\n",
                        error_get_pretty(err));
         error_free(err);
     }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index f90efe590c..bbb21f3583 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -2601,10 +2601,8 @@ Arguments:
 Example:
 
 -> { "execute": "query-migrate-capabilities" }
-<- { "return": {
-        "capabilities" :  [ { "capability" : "xbzrle", "state" : false } ]
-     }
-   }
+<- { "return": [ { "state": false, "capability": "xbzrle" } ] }
+
 EQMP
 
     {
diff --git a/savevm.c b/savevm.c
index 304d1effe5..b947e6a303 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2388,162 +2388,3 @@ void vmstate_register_ram_global(MemoryRegion *mr)
 {
     vmstate_register_ram(mr, NULL);
 }
-
-/*
-  page = zrun nzrun
-       | zrun nzrun page
-
-  zrun = length
-
-  nzrun = length byte...
-
-  length = uleb128 encoded integer
- */
-int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
-                         uint8_t *dst, int dlen)
-{
-    uint32_t zrun_len = 0, nzrun_len = 0;
-    int d = 0, i = 0;
-    long res, xor;
-    uint8_t *nzrun_start = NULL;
-
-    g_assert(!(((uintptr_t)old_buf | (uintptr_t)new_buf | slen) %
-               sizeof(long)));
-
-    while (i < slen) {
-        /* overflow */
-        if (d + 2 > dlen) {
-            return -1;
-        }
-
-        /* not aligned to sizeof(long) */
-        res = (slen - i) % sizeof(long);
-        while (res && old_buf[i] == new_buf[i]) {
-            zrun_len++;
-            i++;
-            res--;
-        }
-
-        /* word at a time for speed */
-        if (!res) {
-            while (i < slen &&
-                   (*(long *)(old_buf + i)) == (*(long *)(new_buf + i))) {
-                i += sizeof(long);
-                zrun_len += sizeof(long);
-            }
-
-            /* go over the rest */
-            while (i < slen && old_buf[i] == new_buf[i]) {
-                zrun_len++;
-                i++;
-            }
-        }
-
-        /* buffer unchanged */
-        if (zrun_len == slen) {
-            return 0;
-        }
-
-        /* skip last zero run */
-        if (i == slen) {
-            return d;
-        }
-
-        d += uleb128_encode_small(dst + d, zrun_len);
-
-        zrun_len = 0;
-        nzrun_start = new_buf + i;
-
-        /* overflow */
-        if (d + 2 > dlen) {
-            return -1;
-        }
-        /* not aligned to sizeof(long) */
-        res = (slen - i) % sizeof(long);
-        while (res && old_buf[i] != new_buf[i]) {
-            i++;
-            nzrun_len++;
-            res--;
-        }
-
-        /* word at a time for speed, use of 32-bit long okay */
-        if (!res) {
-            /* truncation to 32-bit long okay */
-            long mask = (long)0x0101010101010101ULL;
-            while (i < slen) {
-                xor = *(long *)(old_buf + i) ^ *(long *)(new_buf + i);
-                if ((xor - mask) & ~xor & (mask << 7)) {
-                    /* found the end of an nzrun within the current long */
-                    while (old_buf[i] != new_buf[i]) {
-                        nzrun_len++;
-                        i++;
-                    }
-                    break;
-                } else {
-                    i += sizeof(long);
-                    nzrun_len += sizeof(long);
-                }
-            }
-        }
-
-        d += uleb128_encode_small(dst + d, nzrun_len);
-        /* overflow */
-        if (d + nzrun_len > dlen) {
-            return -1;
-        }
-        memcpy(dst + d, nzrun_start, nzrun_len);
-        d += nzrun_len;
-        nzrun_len = 0;
-    }
-
-    return d;
-}
-
-int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen)
-{
-    int i = 0, d = 0;
-    int ret;
-    uint32_t count = 0;
-
-    while (i < slen) {
-
-        /* zrun */
-        if ((slen - i) < 2) {
-            return -1;
-        }
-
-        ret = uleb128_decode_small(src + i, &count);
-        if (ret < 0 || (i && !count)) {
-            return -1;
-        }
-        i += ret;
-        d += count;
-
-        /* overflow */
-        if (d > dlen) {
-            return -1;
-        }
-
-        /* nzrun */
-        if ((slen - i) < 2) {
-            return -1;
-        }
-
-        ret = uleb128_decode_small(src + i, &count);
-        if (ret < 0 || !count) {
-            return -1;
-        }
-        i += ret;
-
-        /* overflow */
-        if (d + count > dlen || i + count > slen) {
-            return -1;
-        }
-
-        memcpy(dst + d, src + i, count);
-        d += count;
-        i += count;
-    }
-
-    return d;
-}
diff --git a/tests/Makefile b/tests/Makefile
index c681cebd18..abe9c2a6c4 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -50,6 +50,8 @@ check-unit-y += tests/test-hbitmap$(EXESUF)
 check-unit-y += tests/test-x86-cpuid$(EXESUF)
 # all code tested by test-x86-cpuid is inside topology.h
 gcov-files-test-x86-cpuid-y =
+check-unit-y += tests/test-xbzrle$(EXESUF)
+gcov-files-test-xbzrle-y = xbzrle.c
 
 check-block-$(CONFIG_POSIX) += tests/qemu-iotests-quick.sh
 
@@ -98,6 +100,7 @@ tests/test-thread-pool$(EXESUF): tests/test-thread-pool.o $(block-obj-y) libqemu
 tests/test-iov$(EXESUF): tests/test-iov.o libqemuutil.a
 tests/test-hbitmap$(EXESUF): tests/test-hbitmap.o libqemuutil.a libqemustub.a
 tests/test-x86-cpuid$(EXESUF): tests/test-x86-cpuid.o
+tests/test-xbzrle$(EXESUF): tests/test-xbzrle.o xbzrle.o page_cache.o libqemuutil.a
 
 tests/test-qapi-types.c tests/test-qapi-types.h :\
 $(SRC_PATH)/qapi-schema-test.json $(SRC_PATH)/scripts/qapi-types.py
diff --git a/tests/test-xbzrle.c b/tests/test-xbzrle.c
new file mode 100644
index 0000000000..db93b0a3d2
--- /dev/null
+++ b/tests/test-xbzrle.c
@@ -0,0 +1,196 @@
+/*
+ * Xor Based Zero Run Length Encoding unit tests.
+ *
+ * Copyright 2013 Red Hat, Inc. and/or its affiliates
+ *
+ * Authors:
+ *  Orit Wasserman  <owasserm@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <strings.h>
+#include <string.h>
+#include <sys/time.h>
+#include <assert.h>
+#include "qemu-common.h"
+#include "include/migration/migration.h"
+
+#define PAGE_SIZE 4096
+
+static void test_uleb(void)
+{
+    uint32_t i, val;
+    uint8_t buf[2];
+    int encode_ret, decode_ret;
+
+    for (i = 0; i <= 0x3fff; i++) {
+        encode_ret = uleb128_encode_small(&buf[0], i);
+        decode_ret = uleb128_decode_small(&buf[0], &val);
+        g_assert(encode_ret == decode_ret);
+        g_assert(i == val);
+    }
+
+    /* decode invalid value */
+    buf[0] = 0x80;
+    buf[1] = 0x80;
+
+    decode_ret = uleb128_decode_small(&buf[0], &val);
+    g_assert(decode_ret == -1);
+    g_assert(val == 0);
+}
+
+static void test_encode_decode_zero(void)
+{
+    uint8_t *buffer = g_malloc0(PAGE_SIZE);
+    uint8_t *compressed = g_malloc0(PAGE_SIZE);
+    int i = 0;
+    int dlen = 0;
+    int diff_len = g_test_rand_int_range(0, PAGE_SIZE - 1006);
+
+    for (i = diff_len; i > 0; i--) {
+        buffer[1000 + i] = i;
+    }
+
+    buffer[1000 + diff_len + 3] = 103;
+    buffer[1000 + diff_len + 5] = 105;
+
+    /* encode zero page */
+    dlen = xbzrle_encode_buffer(buffer, buffer, PAGE_SIZE, compressed,
+                       PAGE_SIZE);
+    g_assert(dlen == 0);
+
+    g_free(buffer);
+    g_free(compressed);
+}
+
+static void test_encode_decode_unchanged(void)
+{
+    uint8_t *compressed = g_malloc0(PAGE_SIZE);
+    uint8_t *test = g_malloc0(PAGE_SIZE);
+    int i = 0;
+    int dlen = 0;
+    int diff_len = g_test_rand_int_range(0, PAGE_SIZE - 1006);
+
+    for (i = diff_len; i > 0; i--) {
+        test[1000 + i] = i + 4;
+    }
+
+    test[1000 + diff_len + 3] = 107;
+    test[1000 + diff_len + 5] = 109;
+
+    /* test unchanged buffer */
+    dlen = xbzrle_encode_buffer(test, test, PAGE_SIZE, compressed,
+                                PAGE_SIZE);
+    g_assert(dlen == 0);
+
+    g_free(test);
+    g_free(compressed);
+}
+
+static void test_encode_decode_1_byte(void)
+{
+    uint8_t *buffer = g_malloc0(PAGE_SIZE);
+    uint8_t *test = g_malloc0(PAGE_SIZE);
+    uint8_t *compressed = g_malloc(PAGE_SIZE);
+    int dlen = 0, rc = 0;
+    uint8_t buf[2];
+
+    test[PAGE_SIZE - 1] = 1;
+
+    dlen = xbzrle_encode_buffer(buffer, test, PAGE_SIZE, compressed,
+                       PAGE_SIZE);
+    g_assert(dlen == (uleb128_encode_small(&buf[0], 4095) + 2));
+
+    rc = xbzrle_decode_buffer(compressed, dlen, buffer, PAGE_SIZE);
+    g_assert(rc == PAGE_SIZE);
+    g_assert(memcmp(test, buffer, PAGE_SIZE) == 0);
+
+    g_free(buffer);
+    g_free(compressed);
+    g_free(test);
+}
+
+static void test_encode_decode_overflow(void)
+{
+    uint8_t *compressed = g_malloc0(PAGE_SIZE);
+    uint8_t *test = g_malloc0(PAGE_SIZE);
+    uint8_t *buffer = g_malloc0(PAGE_SIZE);
+    int i = 0, rc = 0;
+
+    for (i = 0; i < PAGE_SIZE / 2 - 1; i++) {
+        test[i * 2] = 1;
+    }
+
+    /* encode overflow */
+    rc = xbzrle_encode_buffer(buffer, test, PAGE_SIZE, compressed,
+                              PAGE_SIZE);
+    g_assert(rc == -1);
+
+    g_free(buffer);
+    g_free(compressed);
+    g_free(test);
+}
+
+static void encode_decode_range(void)
+{
+    uint8_t *buffer = g_malloc0(PAGE_SIZE);
+    uint8_t *compressed = g_malloc(PAGE_SIZE);
+    uint8_t *test = g_malloc0(PAGE_SIZE);
+    int i = 0, rc = 0;
+    int dlen = 0;
+
+    int diff_len = g_test_rand_int_range(0, PAGE_SIZE - 1006);
+
+    for (i = diff_len; i > 0; i--) {
+        buffer[1000 + i] = i;
+        test[1000 + i] = i + 4;
+    }
+
+    buffer[1000 + diff_len + 3] = 103;
+    test[1000 + diff_len + 3] = 107;
+
+    buffer[1000 + diff_len + 5] = 105;
+    test[1000 + diff_len + 5] = 109;
+
+    /* test encode/decode */
+    dlen = xbzrle_encode_buffer(test, buffer, PAGE_SIZE, compressed,
+                                PAGE_SIZE);
+
+    rc = xbzrle_decode_buffer(compressed, dlen, test, PAGE_SIZE);
+    g_assert(rc < PAGE_SIZE);
+    g_assert(memcmp(test, buffer, PAGE_SIZE) == 0);
+
+    g_free(buffer);
+    g_free(compressed);
+    g_free(test);
+}
+
+static void test_encode_decode(void)
+{
+    int i;
+
+    for (i = 0; i < 10000; i++) {
+        encode_decode_range();
+    }
+}
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+    g_test_rand_int();
+    g_test_add_func("/xbzrle/uleb", test_uleb);
+    g_test_add_func("/xbzrle/encode_decode_zero", test_encode_decode_zero);
+    g_test_add_func("/xbzrle/encode_decode_unchanged",
+                    test_encode_decode_unchanged);
+    g_test_add_func("/xbzrle/encode_decode_1_byte", test_encode_decode_1_byte);
+    g_test_add_func("/xbzrle/encode_decode_overflow",
+                    test_encode_decode_overflow);
+    g_test_add_func("/xbzrle/encode_decode", test_encode_decode);
+
+    return g_test_run();
+}
diff --git a/xbzrle.c b/xbzrle.c
new file mode 100644
index 0000000000..fbcb35d0e3
--- /dev/null
+++ b/xbzrle.c
@@ -0,0 +1,173 @@
+/*
+ * Xor Based Zero Run Length Encoding
+ *
+ * Copyright 2013 Red Hat, Inc. and/or its affiliates
+ *
+ * Authors:
+ *  Orit Wasserman  <owasserm@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+#include "qemu-common.h"
+#include "include/migration/migration.h"
+
+/*
+  page = zrun nzrun
+       | zrun nzrun page
+
+  zrun = length
+
+  nzrun = length byte...
+
+  length = uleb128 encoded integer
+ */
+int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
+                         uint8_t *dst, int dlen)
+{
+    uint32_t zrun_len = 0, nzrun_len = 0;
+    int d = 0, i = 0;
+    long res, xor;
+    uint8_t *nzrun_start = NULL;
+
+    g_assert(!(((uintptr_t)old_buf | (uintptr_t)new_buf | slen) %
+               sizeof(long)));
+
+    while (i < slen) {
+        /* overflow */
+        if (d + 2 > dlen) {
+            return -1;
+        }
+
+        /* not aligned to sizeof(long) */
+        res = (slen - i) % sizeof(long);
+        while (res && old_buf[i] == new_buf[i]) {
+            zrun_len++;
+            i++;
+            res--;
+        }
+
+        /* word at a time for speed */
+        if (!res) {
+            while (i < slen &&
+                   (*(long *)(old_buf + i)) == (*(long *)(new_buf + i))) {
+                i += sizeof(long);
+                zrun_len += sizeof(long);
+            }
+
+            /* go over the rest */
+            while (i < slen && old_buf[i] == new_buf[i]) {
+                zrun_len++;
+                i++;
+            }
+        }
+
+        /* buffer unchanged */
+        if (zrun_len == slen) {
+            return 0;
+        }
+
+        /* skip last zero run */
+        if (i == slen) {
+            return d;
+        }
+
+        d += uleb128_encode_small(dst + d, zrun_len);
+
+        zrun_len = 0;
+        nzrun_start = new_buf + i;
+
+        /* overflow */
+        if (d + 2 > dlen) {
+            return -1;
+        }
+        /* not aligned to sizeof(long) */
+        res = (slen - i) % sizeof(long);
+        while (res && old_buf[i] != new_buf[i]) {
+            i++;
+            nzrun_len++;
+            res--;
+        }
+
+        /* word at a time for speed, use of 32-bit long okay */
+        if (!res) {
+            /* truncation to 32-bit long okay */
+            long mask = (long)0x0101010101010101ULL;
+            while (i < slen) {
+                xor = *(long *)(old_buf + i) ^ *(long *)(new_buf + i);
+                if ((xor - mask) & ~xor & (mask << 7)) {
+                    /* found the end of an nzrun within the current long */
+                    while (old_buf[i] != new_buf[i]) {
+                        nzrun_len++;
+                        i++;
+                    }
+                    break;
+                } else {
+                    i += sizeof(long);
+                    nzrun_len += sizeof(long);
+                }
+            }
+        }
+
+        d += uleb128_encode_small(dst + d, nzrun_len);
+        /* overflow */
+        if (d + nzrun_len > dlen) {
+            return -1;
+        }
+        memcpy(dst + d, nzrun_start, nzrun_len);
+        d += nzrun_len;
+        nzrun_len = 0;
+    }
+
+    return d;
+}
+
+int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen)
+{
+    int i = 0, d = 0;
+    int ret;
+    uint32_t count = 0;
+
+    while (i < slen) {
+
+        /* zrun */
+        if ((slen - i) < 2) {
+            return -1;
+        }
+
+        ret = uleb128_decode_small(src + i, &count);
+        if (ret < 0 || (i && !count)) {
+            return -1;
+        }
+        i += ret;
+        d += count;
+
+        /* overflow */
+        if (d > dlen) {
+            return -1;
+        }
+
+        /* nzrun */
+        if ((slen - i) < 2) {
+            return -1;
+        }
+
+        ret = uleb128_decode_small(src + i, &count);
+        if (ret < 0 || !count) {
+            return -1;
+        }
+        i += ret;
+
+        /* overflow */
+        if (d + count > dlen || i + count > slen) {
+            return -1;
+        }
+
+        memcpy(dst + d, src + i, count);
+        d += count;
+        i += count;
+    }
+
+    return d;
+}