[kvm-unit-tests PATCH 5/9] migration: Support multiple migrations

Nicholas Piggin
2023-12-22T13:51:42Z

Support multiple migrations by flipping dest file/socket variables to
source after the migration is complete, ready to start again. A new
destination is created if the test outputs the migrate line again.
Test cases may now switch to calling migrate() one or more times.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
lib/migrate.c | 8 ++--
lib/migrate.h | 1 +
scripts/arch-run.bash | 93 +++++++++++++++++++++++++++++++++++++------
3 files changed, 85 insertions(+), 17 deletions(-)

diff --git a/lib/migrate.c b/lib/migrate.c
index 527e63ae..b7721659 100644
--- a/lib/migrate.c
+++ b/lib/migrate.c
@@ -8,8 +8,10 @@
#include <libcflat.h>
#include "migrate.h"

-/* static for now since we only support migrating exactly once per test. */
-static void migrate(void)
+/*
+ * Initiate migration and wait for it to complete.
+ */
+void migrate(void)
{
puts("Now migrate the VM, then press a key to continue...\n");
(void)getchar();
@@ -19,8 +21,6 @@ static void migrate(void)
/*
* Initiate migration and wait for it to complete.
* If this function is called more than once, it is a no-op.
- * Since migrate_cmd can only migrate exactly once this function can
- * simplify the control flow, especially when skipping tests.
*/
void migrate_once(void)
{
diff --git a/lib/migrate.h b/lib/migrate.h
index 3c94e6af..2af06a72 100644
--- a/lib/migrate.h
+++ b/lib/migrate.h
@@ -6,4 +6,5 @@
* Author: Nico Boehr <nrb@linux.ibm.com>
*/

+void migrate(void);
void migrate_once(void);
diff --git a/scripts/arch-run.bash b/scripts/arch-run.bash
index 8fbfc50c..1ea0f8bc 100644
--- a/scripts/arch-run.bash
+++ b/scripts/arch-run.bash
@@ -132,29 +132,76 @@ run_migration ()
migsock=$(mktemp -u -t mig-helper-socket.XXXXXXXXXX)
migout1=$(mktemp -t mig-helper-stdout1.XXXXXXXXXX)
migout_fifo1=$(mktemp -u -t mig-helper-fifo-stdout1.XXXXXXXXXX)
+ migout2=$(mktemp -t mig-helper-stdout2.XXXXXXXXXX)
+ migout_fifo2=$(mktemp -u -t mig-helper-fifo-stdout2.XXXXXXXXXX)
qmp1=$(mktemp -u -t mig-helper-qmp1.XXXXXXXXXX)
qmp2=$(mktemp -u -t mig-helper-qmp2.XXXXXXXXXX)
fifo=$(mktemp -u -t mig-helper-fifo.XXXXXXXXXX)

# race here between file creation and trap
trap "trap - TERM ; kill 0 ; exit 2" INT TERM
- trap "rm -f ${migout1} ${migsock} ${qmp1} ${qmp2} ${fifo}" RETURN EXIT
+ trap "rm -f ${migout1} ${migout2} ${migout_fifo1} ${migout_fifo2} ${migsock} ${qmp1} ${qmp2} ${fifo}" RETURN EXIT

qmpout1=/dev/null
qmpout2=/dev/null
+ migcmdline=$@

- eval "$@" -chardev socket,id=mon1,path=${qmp1},server=on,wait=off \
+ mkfifo ${migout_fifo1}
+ mkfifo ${migout_fifo2}
+
+ eval "$migcmdline" \
+ -chardev socket,id=mon1,path=${qmp1},server=on,wait=off \
-mon chardev=mon1,mode=control > ${migout_fifo1} &
live_pid=$!
cat ${migout_fifo1} | tee ${migout1} &

- # We have to use cat to open the named FIFO, because named FIFO's, unlike
- # pipes, will block on open() until the other end is also opened, and that
- # totally breaks QEMU...
+ # The test must prompt the user to migrate, so wait for the "migrate"
+ # keyword
+ while ! grep -q -i "Now migrate the VM" < ${migout1} ; do
+ if ! ps -p ${live_pid} > /dev/null ; then
+ echo "ERROR: Test exit before migration point." >&2
+ qmp ${qmp1} '"quit"'> ${qmpout1} 2>/dev/null
+ return 3
+ fi
+ sleep 0.1
+ done
+
+ # This starts the first source QEMU in advance of the test reaching the
+ # migration point, since we expect at least one migration. Subsequent
+ # sources are started as the test hits migrate keywords.
+ do_migration || return $?
+
+ while ps -p ${live_pid} > /dev/null ; do
+ # Wait for EXIT or further migrations
+ if ! grep -q -i "Now migrate the VM" < ${migout1} ; then
+ sleep 0.1
+ else
+ do_migration || return $?
+ fi
+ done
+
+ wait ${live_pid}
+ ret=$?
+
+ while (( $(jobs -r | wc -l) > 0 )); do
+ sleep 0.1
+ done
+
+ return $ret
+}
+
+do_migration ()
+{
+ # We have to use cat to open the named FIFO, because named FIFO's,
+ # unlike pipes, will block on open() until the other end is also
+ # opened, and that totally breaks QEMU...
mkfifo ${fifo}
- eval "$@" -chardev socket,id=mon2,path=${qmp2},server=on,wait=off \
- -mon chardev=mon2,mode=control -incoming unix:${migsock} < <(cat ${fifo}) &
+ eval "$migcmdline" \
+ -chardev socket,id=mon2,path=${qmp2},server=on,wait=off \
+ -mon chardev=mon2,mode=control -incoming unix:${migsock} \
+ < <(cat ${fifo}) > ${migout_fifo2} &
incoming_pid=$!
+ cat ${migout_fifo2} | tee ${migout2} &

# The test must prompt the user to migrate, so wait for the "migrate" keyword
while ! grep -q -i "Now migrate the VM" < ${migout1} ; do
@@ -165,7 +212,7 @@ run_migration ()
qmp ${qmp2} '"quit"'> ${qmpout2} 2>/dev/null
return 3
fi
- sleep 1
+ sleep 0.1
done

# Wait until the destination has created the incoming and qmp sockets
@@ -177,7 +224,7 @@ run_migration ()
# Wait for the migration to complete
migstatus=`qmp ${qmp1} '"query-migrate"' | grep return`
while ! grep -q '"completed"' <<<"$migstatus" ; do
- sleep 1
+ sleep 0.1
if ! migstatus=`qmp ${qmp1} '"query-migrate"'`; then
echo "ERROR: Querying migration state failed." >&2
echo > ${fifo}
@@ -193,14 +240,34 @@ run_migration ()
return 2
fi
done
+
qmp ${qmp1} '"quit"'> ${qmpout1} 2>/dev/null
+
+ # keypress to dst so getchar completes and test continues
echo > ${fifo}
- wait $incoming_pid
+ rm ${fifo}
+
+ # Ensure the incoming socket is removed, ready for next destination
+ if [ -S ${migsock} ] ; then
+ echo "ERROR: Incoming migration socket not removed after migration." >& 2
+ qmp ${qmp2} '"quit"'> ${qmpout2} 2>/dev/null
+ return 2
+ fi
+
+ wait ${live_pid}
ret=$?

- while (( $(jobs -r | wc -l) > 0 )); do
- sleep 0.5
- done
+ # Now flip the variables because dest becomes source
+ live_pid=${incoming_pid}
+ tmp=${migout1}
+ migout1=${migout2}
+ migout2=${tmp}
+ tmp=${migout_fifo1}
+ migout_fifo1=${migout_fifo2}
+ migout_fifo2=${tmp}
+ tmp=${qmp1}
+ qmp1=${qmp2}
+ qmp2=${tmp}

return $ret
}
--
2.42.0