Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20210208a' into staging

Migration pull 2021-02-08

v2
  Dropped vmstate: Fix memory leak in vmstate_handle_alloc
    Broke on Power
  Added migration: only check page size match if RAM postcopy is enabled

# gpg: Signature made Mon 08 Feb 2021 11:28:14 GMT
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20210208a: (27 commits)
  migration: only check page size match if RAM postcopy is enabled
  migration: introduce snapshot-{save, load, delete} QMP commands
  iotests: fix loading of common.config from tests/ subdir
  iotests: add support for capturing and matching QMP events
  migration: introduce a delete_snapshot wrapper
  migration: wire up support for snapshot device selection
  migration: control whether snapshots are ovewritten
  block: rename and alter bdrv_all_find_snapshot semantics
  block: allow specifying name of block device for vmstate storage
  block: add ability to specify list of blockdevs during snapshot
  migration: stop returning errno from load_snapshot()
  migration: Make save_snapshot() return bool, not 0/-1
  block: push error reporting into bdrv_all_*_snapshot functions
  migration: Display the migration blockers
  migration: Add blocker information
  migration: Fix a few absurdly defective error messages
  migration: Fix cache_init()'s "Failed to allocate" error messages
  migration: Clean up signed vs. unsigned XBZRLE cache-size
  migration: Fix migrate-set-parameters argument validation
  migration: introduce 'userfaultfd-wrlat.py' script
  ...

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

3 files changed, 119 insertions, 9 deletions

diff --git a/tests/qemu-iotests/267.out b/tests/qemu-iotests/267.out
index 27471ffae8..7176e376e1 100644
--- a/tests/qemu-iotests/267.out
+++ b/tests/qemu-iotests/267.out
@@ -6,11 +6,11 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
 Testing:
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
-Error: No block device can accept snapshots
+Error: no block device can store vmstate for snapshot
 (qemu) info snapshots
-No available block device supports snapshots
+no block device can store vmstate for snapshot
 (qemu) loadvm snap0
-Error: No block device supports snapshots
+Error: no block device can store vmstate for snapshot
 (qemu) quit
 
 
@@ -22,7 +22,7 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 Error: Device 'none0' is writable but does not support snapshots
 (qemu) info snapshots
-No available block device supports snapshots
+no block device can store vmstate for snapshot
 (qemu) loadvm snap0
 Error: Device 'none0' is writable but does not support snapshots
 (qemu) quit
@@ -58,7 +58,7 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 Error: Device 'virtio0' is writable but does not support snapshots
 (qemu) info snapshots
-No available block device supports snapshots
+no block device can store vmstate for snapshot
 (qemu) loadvm snap0
 Error: Device 'virtio0' is writable but does not support snapshots
 (qemu) quit
@@ -83,7 +83,7 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 Error: Device 'file' is writable but does not support snapshots
 (qemu) info snapshots
-No available block device supports snapshots
+no block device can store vmstate for snapshot
 (qemu) loadvm snap0
 Error: Device 'file' is writable but does not support snapshots
 (qemu) quit
diff --git a/tests/qemu-iotests/common.qemu b/tests/qemu-iotests/common.qemu
index ef105dfc39..0fc52d20d7 100644
--- a/tests/qemu-iotests/common.qemu
+++ b/tests/qemu-iotests/common.qemu
@@ -53,6 +53,15 @@ _in_fd=4
 # If $mismatch_only is set, only non-matching responses will
 # be echoed.
 #
+# If $capture_events is non-empty, then any QMP event names it lists
+# will not be echoed out, but instead collected in the $QEMU_EVENTS
+# variable. The _wait_event function can later be used to receive
+# the cached events.
+#
+# If $only_capture_events is set to anything but an empty string,
+# then an error will be raised if a QMP message is seen which is
+# not an event listed in $capture_events.
+#
 # If $success_or_failure is set, the meaning of the arguments is
 # changed as follows:
 # $2: A string to search for in the response; if found, this indicates
@@ -78,6 +87,31 @@ _timed_wait_for()
     QEMU_STATUS[$h]=0
     while IFS= read -t ${QEMU_COMM_TIMEOUT} resp <&${QEMU_OUT[$h]}
     do
+        if [ -n "$capture_events" ]; then
+            capture=0
+            local evname
+            for evname in $capture_events
+            do
+                case ${resp} in
+                    *\"event\":\ \"${evname}\"* ) capture=1 ;;
+                esac
+            done
+            if [ $capture = 1 ];
+            then
+                ev=$(echo "${resp}" | tr -d '\r' | tr % .)
+                QEMU_EVENTS="${QEMU_EVENTS:+${QEMU_EVENTS}%}${ev}"
+                if [ -n "$only_capture_events" ]; then
+                    return
+                else
+                    continue
+                fi
+            fi
+        fi
+        if [ -n "$only_capture_events" ]; then
+            echo "Only expected $capture_events but got ${resp}"
+            exit 1
+        fi
+
         if [ -z "${silent}" ] && [ -z "${mismatch_only}" ]; then
             echo "${resp}" | _filter_testdir | _filter_qemu \
                            | _filter_qemu_io | _filter_qmp | _filter_hmp
@@ -172,12 +206,82 @@ _send_qemu_cmd()
         let count--;
     done
     if [ ${QEMU_STATUS[$h]} -ne 0 ] && [ -z "${qemu_error_no_exit}" ]; then
-        echo "Timeout waiting for ${1} on handle ${h}"
+        echo "Timeout waiting for command ${1} response on handle ${h}"
         exit 1 #Timeout means the test failed
     fi
 }
 
 
+# Check event cache for a named QMP event
+#
+# Input parameters:
+# $1:       Name of the QMP event to check for
+#
+# Checks if the named QMP event that was previously captured
+# into $QEMU_EVENTS. When matched, the QMP event will be echoed
+# and the $matched variable set to 1.
+#
+# _wait_event is more suitable for test usage in most cases
+_check_cached_events()
+{
+    local evname=${1}
+
+    local match="\"event\": \"$evname\""
+
+    matched=0
+    if [ -n "$QEMU_EVENTS" ]; then
+        CURRENT_QEMU_EVENTS=$QEMU_EVENTS
+        QEMU_EVENTS=
+        old_IFS=$IFS
+        IFS="%"
+        for ev in $CURRENT_QEMU_EVENTS
+        do
+            grep -q "$match" < <(echo "${ev}")
+            if [ $? -eq 0 ] && [ $matched = 0 ]; then
+                echo "${ev}" | _filter_testdir | _filter_qemu \
+                           | _filter_qemu_io | _filter_qmp | _filter_hmp
+                matched=1
+            else
+                QEMU_EVENTS="${QEMU_EVENTS:+${QEMU_EVENTS}%}${ev}"
+            fi
+        done
+        IFS=$old_IFS
+    fi
+}
+
+# Wait for a named QMP event
+#
+# Input parameters:
+# $1:       QEMU handle to use
+# $2:       Name of the QMP event to wait for
+#
+# Checks if the named QMP even was previously captured
+# into $QEMU_EVENTS. If none are present, then waits for the
+# event to arrive on the QMP channel. When matched, the QMP
+# event will be echoed
+_wait_event()
+{
+    local h=${1}
+    local evname=${2}
+
+    while true
+    do
+        _check_cached_events $evname
+
+        if [ $matched = 1 ];
+        then
+            return
+        fi
+
+        only_capture_events=1 qemu_error_no_exit=1 _timed_wait_for ${h}
+
+        if [ ${QEMU_STATUS[$h]} -ne 0 ] ; then
+            echo "Timeout waiting for event ${evname} on handle ${h}"
+            exit 1 #Timeout means the test failed
+        fi
+    done
+}
+
 # Launch a QEMU process.
 #
 # Input parameters:
diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 297acf9b6a..77c37e8312 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -109,8 +109,14 @@ peek_file_raw()
     dd if="$1" bs=1 skip="$2" count="$3" status=none
 }
 
-
-if ! . ./common.config
+config=common.config
+test -f $config || config=../common.config
+if ! test -f $config
+then
+    echo "$0: failed to find common.config"
+    exit 1
+fi
+if ! . $config
     then
     echo "$0: failed to source common.config"
     exit 1