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| author | Maxiwell S. Garcia <maxiwell@linux.ibm.com> | 2019-07-11 16:47:02 -0300 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2019-08-21 17:17:11 +1000 |
| commit | d14f33976282a8744ca1bf1d64e73996c145aa3f (patch) | |
| tree | f7ebdeab615939ac1aa5b0ab5ba4583876236ec3 | |
| parent | d15d4ad64f12cf88df8eac0cc910fa0637ab15e0 (diff) | |
| download | qemu-d14f33976282a8744ca1bf1d64e73996c145aa3f.zip qemu-d14f33976282a8744ca1bf1d64e73996c145aa3f.tar.gz qemu-d14f33976282a8744ca1bf1d64e73996c145aa3f.tar.bz2 | |
migration: Do not re-read the clock on pre_save in case of paused guest
Re-read the timebase before migrate was ported from x86 commit:
6053a86fe7bd: kvmclock: reduce kvmclock difference on migration
The clock move makes the guest knows about the paused time between
the stop and migrate commands. This is an issue in an already-paused
VM because some side effects, like process stalls, could happen
after migration.
So, this patch checks the runstate of guest in the pre_save handler and
do not re-reads the timebase in case of paused state (cold migration).
Signed-off-by: Maxiwell S. Garcia <maxiwell@linux.ibm.com>
Message-Id: <20190711194702.26598-1-maxiwell@linux.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
| -rw-r--r-- | hw/ppc/ppc.c | 13 | ||||
| -rw-r--r-- | target/ppc/cpu-qom.h | 1 |
2 files changed, 10 insertions, 4 deletions
diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c index 7963fee..52a18eb 100644 --- a/hw/ppc/ppc.c +++ b/hw/ppc/ppc.c @@ -1011,6 +1011,8 @@ static void timebase_save(PPCTimebase *tb) * there is no need to update it from KVM here */ tb->guest_timebase = ticks + first_ppc_cpu->env.tb_env->tb_offset; + + tb->runstate_paused = runstate_check(RUN_STATE_PAUSED); } static void timebase_load(PPCTimebase *tb) @@ -1054,9 +1056,9 @@ void cpu_ppc_clock_vm_state_change(void *opaque, int running, } /* - * When migrating, read the clock just before migration, - * so that the guest clock counts during the events - * between: + * When migrating a running guest, read the clock just + * before migration, so that the guest clock counts + * during the events between: * * * vm_stop() * * @@ -1071,7 +1073,10 @@ static int timebase_pre_save(void *opaque) { PPCTimebase *tb = opaque; - timebase_save(tb); + /* guest_timebase won't be overridden in case of paused guest */ + if (!tb->runstate_paused) { + timebase_save(tb); + } return 0; } diff --git a/target/ppc/cpu-qom.h b/target/ppc/cpu-qom.h index a2f202f..5769fb7 100644 --- a/target/ppc/cpu-qom.h +++ b/target/ppc/cpu-qom.h @@ -201,6 +201,7 @@ typedef struct PowerPCCPUClass { typedef struct PPCTimebase { uint64_t guest_timebase; int64_t time_of_the_day_ns; + bool runstate_paused; } PPCTimebase; extern const VMStateDescription vmstate_ppc_timebase; |