dump: Add command interface for kdump-raw formats

The QMP dump API represents the dump format as an enumeration. Add three
new enumerators, one for each supported kdump compression, each named
"kdump-raw-*".

For the HMP command line, rather than adding a new flag corresponding to
each format, it seems more human-friendly to add a single flag "-R" to
switch the kdump formats to "raw" mode. The choice of "-R" also
correlates nicely to the "makedumpfile -R" option, which would serve to
reassemble a flattened vmcore.

Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
[ Marc-André: replace loff_t with off_t, indent fixes ]
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230918233233.1431858-4-stephen.s.brennan@oracle.com>

dump/dump-hmp-cmds.c

@@ -19,6 +19,7 @@ void hmp_dump_guest_memory(Monitor *mon, const QDict *qdict)
     bool paging = qdict_get_try_bool(qdict, "paging", false);
     bool zlib = qdict_get_try_bool(qdict, "zlib", false);
     bool lzo = qdict_get_try_bool(qdict, "lzo", false);
+    bool raw = qdict_get_try_bool(qdict, "raw", false);
     bool snappy = qdict_get_try_bool(qdict, "snappy", false);
     const char *file = qdict_get_str(qdict, "filename");
     bool has_begin = qdict_haskey(qdict, "begin");
@@ -40,17 +41,29 @@ void hmp_dump_guest_memory(Monitor *mon, const QDict *qdict)
         dump_format = DUMP_GUEST_MEMORY_FORMAT_WIN_DMP;
     }
 
-    if (zlib) {
+    if (zlib && raw) {
+        if (raw) {
+            dump_format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_RAW_ZLIB;
+        } else {
             dump_format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_ZLIB;
         }
+    }
 
     if (lzo) {
+        if (raw) {
+            dump_format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_RAW_LZO;
+        } else {
             dump_format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_LZO;
         }
+    }
 
     if (snappy) {
+        if (raw) {
+            dump_format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_RAW_SNAPPY;
+        } else {
             dump_format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_SNAPPY;
         }
+    }
 
     if (has_begin) {
         begin = qdict_get_int(qdict, "begin");

dump/dump.c

@@ -2090,6 +2090,7 @@ void qmp_dump_guest_memory(bool paging, const char *file,
     int fd = -1;
     DumpState *s;
     bool detach_p = false;
+    bool kdump_raw = false;
 
     if (runstate_check(RUN_STATE_INMIGRATE)) {
         error_setg(errp, "Dump not allowed during incoming migration.");
@@ -2103,6 +2104,29 @@ void qmp_dump_guest_memory(bool paging, const char *file,
         return;
     }
 
+    /*
+     * externally, we represent kdump-raw-* as separate formats, but internally
+     * they are handled the same, except for the "raw" flag
+     */
+    if (has_format) {
+        switch (format) {
+        case DUMP_GUEST_MEMORY_FORMAT_KDUMP_RAW_ZLIB:
+            format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_ZLIB;
+            kdump_raw = true;
+            break;
+        case DUMP_GUEST_MEMORY_FORMAT_KDUMP_RAW_LZO:
+            format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_LZO;
+            kdump_raw = true;
+            break;
+        case DUMP_GUEST_MEMORY_FORMAT_KDUMP_RAW_SNAPPY:
+            format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_SNAPPY;
+            kdump_raw = true;
+            break;
+        default:
+            break;
+        }
+    }
+
     /*
      * kdump-compressed format need the whole memory dumped, so paging or
      * filter is not supported here.
@@ -2166,6 +2190,10 @@ void qmp_dump_guest_memory(bool paging, const char *file,
         error_setg(errp, QERR_INVALID_PARAMETER, "protocol");
         return;
     }
+    if (kdump_raw && lseek(fd, 0, SEEK_CUR) == (off_t) -1) {
+        error_setg(errp, "kdump-raw formats require a seekable file");
+        return;
+    }
 
     if (!dump_migration_blocker) {
         error_setg(&dump_migration_blocker,
@@ -2186,7 +2214,7 @@ void qmp_dump_guest_memory(bool paging, const char *file,
     dump_state_prepare(s);
 
     dump_init(s, fd, has_format, format, paging, has_begin,
-              begin, length, false, errp);
+              begin, length, kdump_raw, errp);
     if (*errp) {
         qatomic_set(&s->status, DUMP_STATUS_FAILED);
         return;
@@ -2214,15 +2242,18 @@ DumpGuestMemoryCapability *qmp_query_dump_guest_memory_capability(Error **errp)
 
     /* kdump-zlib is always available */
     QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_KDUMP_ZLIB);
+    QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_KDUMP_RAW_ZLIB);
 
     /* add new item if kdump-lzo is available */
 #ifdef CONFIG_LZO
     QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_KDUMP_LZO);
+    QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_KDUMP_RAW_LZO);
 #endif
 
     /* add new item if kdump-snappy is available */
 #ifdef CONFIG_SNAPPY
     QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_KDUMP_SNAPPY);
+    QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_KDUMP_RAW_SNAPPY);
 #endif
 
     if (win_dump_available(NULL)) {

hmp-commands.hx

@@ -1085,14 +1085,16 @@ ERST
 
     {
         .name       = "dump-guest-memory",
-        .args_type  = "paging:-p,detach:-d,windmp:-w,zlib:-z,lzo:-l,snappy:-s,filename:F,begin:l?,length:l?",
+        .args_type  = "paging:-p,detach:-d,windmp:-w,zlib:-z,lzo:-l,snappy:-s,raw:-R,filename:F,begin:l?,length:l?",
-        .params     = "[-p] [-d] [-z|-l|-s|-w] filename [begin length]",
+        .params     = "[-p] [-d] [-z|-l|-s|-w] [-R] filename [begin length]",
         .help       = "dump guest memory into file 'filename'.\n\t\t\t"
                       "-p: do paging to get guest's memory mapping.\n\t\t\t"
                       "-d: return immediately (do not wait for completion).\n\t\t\t"
                       "-z: dump in kdump-compressed format, with zlib compression.\n\t\t\t"
                       "-l: dump in kdump-compressed format, with lzo compression.\n\t\t\t"
                       "-s: dump in kdump-compressed format, with snappy compression.\n\t\t\t"
+                      "-R: when using kdump (-z, -l, -s), use raw rather than makedumpfile-flattened\n\t\t\t"
+                      "    format\n\t\t\t"
                       "-w: dump in Windows crashdump format (can be used instead of ELF-dump converting),\n\t\t\t"
                       "    for Windows x86 and x64 guests with vmcoreinfo driver only.\n\t\t\t"
                       "begin: the starting physical address.\n\t\t\t"
@@ -1115,6 +1117,9 @@ SRST
     dump in kdump-compressed format, with lzo compression.
   ``-s``
     dump in kdump-compressed format, with snappy compression.
+  ``-R``
+    when using kdump (-z, -l, -s), use raw rather than makedumpfile-flattened
+    format
   ``-w``
     dump in Windows crashdump format (can be used instead of ELF-dump converting),
     for Windows x64 guests with vmcoreinfo driver only

qapi/dump.json

@@ -15,11 +15,23 @@
 #
 # @elf: elf format
 #
-# @kdump-zlib: kdump-compressed format with zlib-compressed
+# @kdump-zlib: makedumpfile flattened, kdump-compressed format with zlib
+#     compression
 #
-# @kdump-lzo: kdump-compressed format with lzo-compressed
+# @kdump-lzo: makedumpfile flattened, kdump-compressed format with lzo
+#     compression
 #
-# @kdump-snappy: kdump-compressed format with snappy-compressed
+# @kdump-snappy: makedumpfile flattened, kdump-compressed format with snappy
+#     compression
+#
+# @kdump-raw-zlib: raw assembled kdump-compressed format with zlib compression
+#     (since 8.2)
+#
+# @kdump-raw-lzo: raw assembled kdump-compressed format with lzo compression
+#     (since 8.2)
+#
+# @kdump-raw-snappy: raw assembled kdump-compressed format with snappy
+#     compression (since 8.2)
 #
 # @win-dmp: Windows full crashdump format, can be used instead of ELF
 #     converting (since 2.13)
@@ -27,7 +39,11 @@
 # Since: 2.0
 ##
 { 'enum': 'DumpGuestMemoryFormat',
-  'data': [ 'elf', 'kdump-zlib', 'kdump-lzo', 'kdump-snappy', 'win-dmp' ] }
+  'data': [
+      'elf',
+      'kdump-zlib', 'kdump-lzo', 'kdump-snappy',
+      'kdump-raw-zlib', 'kdump-raw-lzo', 'kdump-raw-snappy',
+      'win-dmp' ] }
 
 ##
 # @dump-guest-memory: