xemu/target
David Gibson 75e972dab5 migration: Mark CPU states dirty before incoming migration/loadvm
As a rule, CPU internal state should never be updated when
!cpu->kvm_vcpu_dirty (or the HAX equivalent).  If that is done, then
subsequent calls to cpu_synchronize_state() - usually safe and idempotent -
will clobber state.

However, we routinely do this during a loadvm or incoming migration.
Usually this is called shortly after a reset, which will clear all the cpu
dirty flags with cpu_synchronize_all_post_reset().  Nothing is expected
to set the dirty flags again before the cpu state is loaded from the
incoming stream.

This means that it isn't safe to call cpu_synchronize_state() from a
post_load handler, which is non-obvious and potentially inconvenient.

We could cpu_synchronize_all_state() before the loadvm, but that would be
overkill since a) we expect the state to already be synchronized from the
reset and b) we expect to completely rewrite the state with a call to
cpu_synchronize_all_post_init() at the end of qemu_loadvm_state().

To clear this up, this patch introduces cpu_synchronize_pre_loadvm() and
associated helpers, which simply marks the cpu state as dirty without
actually changing anything.  i.e. it says we want to discard any existing
KVM (or HAX) state and replace it with what we're going to load.

Cc: Juan Quintela <quintela@redhat.com>
Cc: Dave Gilbert <dgilbert@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Juan Quintela <quintela@redhat.com>
2017-06-06 08:53:24 +10:00
..
alpha migration: Remove unneeded includes of migration/vmstate.h 2017-06-01 18:49:22 +02:00
arm target/arm: add data cache invalidation cp15 instruction to cortex-r5 2017-06-04 18:42:55 +03:00
cris qom/cpu: move tlb_flush to cpu_common_reset 2017-01-13 14:24:31 +00:00
hppa migration: Remove unneeded includes of migration/vmstate.h 2017-06-01 18:49:22 +02:00
i386 migration: Mark CPU states dirty before incoming migration/loadvm 2017-06-06 08:53:24 +10:00
lm32 qom/cpu: move tlb_flush to cpu_common_reset 2017-01-13 14:24:31 +00:00
m68k This is the same as the v3 posted except a re-base and a few extra signoffs 2017-01-16 18:23:02 +00:00
microblaze cputlb: drop flush_global flag from tlb_flush 2017-01-13 14:24:37 +00:00
mips target/mips: fix delay slot detection in gen_msa_branch() 2017-03-20 11:19:14 +00:00
moxie qom/cpu: move tlb_flush to cpu_common_reset 2017-01-13 14:24:31 +00:00
nios2 target/nios2: take BQL around interrupt check 2017-03-14 13:26:37 +01:00
openrisc target/openrisc: Support non-busy idle state using PMR SPR 2017-05-04 09:39:14 +09:00
ppc target/ppc: reset reservation in do_rfi() 2017-05-24 11:39:52 +10:00
s390x migration: Remove unneeded includes of migration/vmstate.h 2017-06-01 18:49:22 +02:00
sh4 target/sh4: fix RTE instruction delay slot 2017-05-30 21:00:56 +02:00
sparc shutdown: Add source information to SHUTDOWN and RESET 2017-05-23 13:28:17 +02:00
tilegx migration: Remove unneeded includes of migration/vmstate.h 2017-06-01 18:49:22 +02:00
tricore qom/cpu: move tlb_flush to cpu_common_reset 2017-01-13 14:24:31 +00:00
unicore32 cputlb: drop flush_global flag from tlb_flush 2017-01-13 14:24:37 +00:00
xtensa target/xtensa fixes for 2.9: 2017-03-18 17:24:49 +00:00