Hello,
In response to patches from Juan [1], this series implements a declarative way
for CPUs to register their CPU-specific VMStateDescription.
There are subtle differences between CPU and devices in how they register
their savevm handlers and VMStateDescription respectively:
* CPUs register one VMStateDescription "cpu_common" plus savevm handlers for
the target-specifics (machine.c:cpu_{save,load}).
Devices register one VMStateDescription with a subsection for common state
where necessary.
* CPUs use their cpu_index field as instance_id.
Devices pass -1 as instance_id, resulting in highest index on the bus plus 1.
Note: The current cpu_index numbering is not hot-unplug-safe.
My code assumes that registering "cpu_common" for CPUArchState (until changed
in CPUState part 9 series) while registering "cpu" for CPUState is compatible,
since by not using DeviceState::vmsd infrastructure registration order remains
guaranteed the same.
Patches 4-5 demonstrate how two VMStateDescription-prepared but not yet
migratable targets would look like if we want to adopt a consistent pattern
for VMStateDescription registration and layout throughout targets.
Question is whether we want to take that legacy burden on us or whether to
simply expose exec.c:vmstate_cpu_common and embed it PCI-like into the
prepared VMStateDescriptions for alpha and openrisc and register them through
DeviceClass::vmsd instead.
An alternative might be registering "cpu_common" as before but with
instance_id -1 and registering "cpu" through DeviceClass::vmsd, since
exec.c:calculate_new_instance_id() takes the name string into account.
But that would be inconsistent with how devices behave VMState-wise.
Targets that have not yet been converted to VMState [1, 2] are left untouched.
Known conflicts:
- CPUState part 9 v1 series (target-*/cpu.c:class_init), to be rebased on this.
Available for testing here:
git://github.com/afaerber/qemu-cpu.git qom-cpu-vmstate.v1
https://github.com/afaerber/qemu-cpu/commits/qom-cpu-vmstate.v1
What triggered this series was moving the halted and interrupt_request fields
from CPU_COMMON to CPUState:
https://lists.nongnu.org/archive/html/qemu-devel/2013-02/msg00203.html
Since both are in vmstate_cpu_common, they needed to be moved together, and
"cpu_common" will need to operate on CPUState then. At the same time x86
can no longer access the halted field from CPUX86State via VMSTATE_ macros,
so either we need to drop uses of such fields (i.e., version 5) or make it
possible to access CPUState fields in x86 VMState through parent_obj field.
Further, in explaining intended uses of S390CPU vs. CPUS390XState I was
reminded that VMState is currently a limiting factor for placing fields into
CPUState-derived types rather than into CPU*State.
Regards,
Andreas
[1] https://lists.nongnu.org/archive/html/qemu-devel/2012-05/msg00524.html
[2] https://lists.nongnu.org/archive/html/qemu-devel/2012-09/msg03451.html
Cc: Juan Quintela <quint...@redhat.com>
Cc: Michael Roth <mdr...@linux.vnet.ibm.com>
Cc: Anthony Liguori <anth...@codemonkey.ws>
Cc: Blue Swirl <blauwir...@gmail.com>
Cc: Aurélien Jarno <aurel...@aurel32.net>
Cc: Eduardo Habkost <ehabk...@redhat.com>
Cc: Igor Mammedov <imamm...@redhat.com>
Cc: Richard Henderson <r...@twiddle.net>
Cc: Michael Walle <mich...@walle.cc>
Cc: Jia Liu <pro...@gmail.com>
Cc: David Gibson <da...@gibson.dropbear.id.au>
Cc: Alexander Graf <ag...@suse.de>
Cc: qemu-...@nongnu.org
Andreas Färber (6):
cpu: Register VMStateDescription through CPUState
target-i386: Update VMStateDescription to X86CPU
target-lm32: Update VMStateDescription to LM32CPU
target-alpha: Register VMStateDescription for AlphaCPU
target-openrisc: Register VMStateDescription for OpenRISCCPU
cpu: Guard cpu_{save,load}() definitions
exec.c | 13 ++-
include/qemu-common.h | 2 +
include/qom/cpu.h | 3 +
target-alpha/cpu-qom.h | 2 +
target-alpha/cpu.c | 3 +
target-alpha/machine.c | 64 ++++++--------
target-i386/cpu-qom.h | 2 +
target-i386/cpu.c | 4 +
target-i386/cpu.h | 2 -
target-i386/machine.c | 215 ++++++++++++++++++++++-----------------------
target-lm32/cpu-qom.h | 2 +
target-lm32/cpu.c | 4 +
target-lm32/cpu.h | 2 -
target-lm32/machine.c | 36 +++-----
target-openrisc/cpu.c | 3 +
target-openrisc/cpu.h | 2 +
target-openrisc/machine.c | 33 +++----
17 Dateien geändert, 200 Zeilen hinzugefügt(+), 192 Zeilen entfernt(-)
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1.7.10.4
