From 50f063769cf74d2d37adbc5b568b545d2562af65 Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Tue, 28 Nov 2017 10:30:08 +0100 Subject: [PATCH 15/21] migration/ram.c: do not set 'postcopy_running' in POSTCOPY_INCOMING_END RH-Author: Laurent Vivier Message-id: <20171128103008.1150-1-lvivier@redhat.com> Patchwork-id: 77931 O-Subject: [RHV7.5 qemu-kvm-rhev PATCH] migration/ram.c: do not set 'postcopy_running' in POSTCOPY_INCOMING_END Bugzilla: 1516956 RH-Acked-by: Peter Xu RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Juan Quintela RH-Acked-by: David Gibson From: Daniel Henrique Barboza When migrating a VM with 'migrate_set_capability postcopy-ram on' a postcopy_state is set during the process, ending up with the state POSTCOPY_INCOMING_END when the migration is over. This postcopy_state is taken into account inside ram_load to check how it will load the memory pages. This same ram_load is called when in a loadvm command. Inside ram_load, the logic to see if we're at postcopy_running state is: postcopy_running = postcopy_state_get() >= POSTCOPY_INCOMING_LISTENING postcopy_state_get() returns this enum type: typedef enum { POSTCOPY_INCOMING_NONE = 0, POSTCOPY_INCOMING_ADVISE, POSTCOPY_INCOMING_DISCARD, POSTCOPY_INCOMING_LISTENING, POSTCOPY_INCOMING_RUNNING, POSTCOPY_INCOMING_END } PostcopyState; In the case where ram_load is executed and postcopy_state is POSTCOPY_INCOMING_END, postcopy_running will be set to 'true' and ram_load will behave like a postcopy is in progress. This scenario isn't achievable in a migration but it is reproducible when executing savevm/loadvm after migrating with 'postcopy-ram on', causing loadvm to fail with Error -22: Source: (qemu) migrate_set_capability postcopy-ram on (qemu) migrate tcp:127.0.0.1:4444 Dest: (qemu) migrate_set_capability postcopy-ram on (qemu) ubuntu1704-intel login: Ubuntu 17.04 ubuntu1704-intel ttyS0 ubuntu1704-intel login: (qemu) (qemu) savevm test1 (qemu) loadvm test1 Unknown combination of migration flags: 0x4 (postcopy mode) error while loading state for instance 0x0 of device 'ram' Error -22 while loading VM state (qemu) This patch fixes this problem by changing the existing logic for postcopy_advised and postcopy_running in ram_load, making them 'false' if we're at POSTCOPY_INCOMING_END state. Signed-off-by: Daniel Henrique Barboza CC: Juan Quintela CC: Dr. David Alan Gilbert Reviewed-by: Peter Xu Reviewed-by: Juan Quintela Reported-by: Balamuruhan S Signed-off-by: Juan Quintela (cherry picked from commit acab30b85db0885ab161aff4c83c550628f6d8ca) Signed-off-by: Laurent Vivier Signed-off-by: Miroslav Rezanina --- migration/ram.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index e18b3e2..fef80fd 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2484,6 +2484,18 @@ static int ram_load_postcopy(QEMUFile *f) return ret; } +static bool postcopy_is_advised(void) +{ + PostcopyState ps = postcopy_state_get(); + return ps >= POSTCOPY_INCOMING_ADVISE && ps < POSTCOPY_INCOMING_END; +} + +static bool postcopy_is_running(void) +{ + PostcopyState ps = postcopy_state_get(); + return ps >= POSTCOPY_INCOMING_LISTENING && ps < POSTCOPY_INCOMING_END; +} + static int ram_load(QEMUFile *f, void *opaque, int version_id) { int flags = 0, ret = 0, invalid_flags = 0; @@ -2493,9 +2505,9 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) * If system is running in postcopy mode, page inserts to host memory must * be atomic */ - bool postcopy_running = postcopy_state_get() >= POSTCOPY_INCOMING_LISTENING; + bool postcopy_running = postcopy_is_running(); /* ADVISE is earlier, it shows the source has the postcopy capability on */ - bool postcopy_advised = postcopy_state_get() >= POSTCOPY_INCOMING_ADVISE; + bool postcopy_advised = postcopy_is_advised(); seq_iter++; -- 1.8.3.1