| Message ID | 20170424220828.1472-4-danielhb@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
Quoting Daniel Henrique Barboza (2017-04-24 17:08:27) > From: Jianjun Duan <duanj@linux.vnet.ibm.com> > > ccs_list in spapr state maintains the device tree related > information on the rtas side for hotplugged devices. In racing > situations between hotplug events and migration operation, a rtas > hotplug event could be migrated from the source guest to target > guest, or the source guest could have not yet finished fetching > the device tree when migration is started, the target will try > to finish fetching the device tree. By migrating ccs_list, the > target can fetch the device tree properly. > > In theory there would be other alternatives besides migrating the > css_list to fix this. For example, we could add a flag that indicates > whether a device is in the middle of the configure_connector during the > migration process, in the post_load we can detect if this flag > is active and then return an error informing the guest to restart the > hotplug process. However, the DRC state can still be modified outside of > hotplug. Using: > > drmgr -c pci -s <drc_index> -r > drmgr -c pci -s <drc_index> -a > > it is possible to return a device to firmware and then later take it > back and reconfigure it. This is not a common case but it's not prohibited, > and performing a migration between these 2 operations would fail because > the default coldplug state on target assumes a configured state in > the source*. Migrating ccs_list is one solution that cover this > case as well. > > ccs_list is put in a subsection in the spapr state VMSD to make > sure migration across different versions is not broken. > > * see http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg01763.html > for more information on this discussion. > > Signed-off-by: Jianjun Duan <duanj@linux.vnet.ibm.com> > Signed-off-by: Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com> > --- > hw/ppc/spapr.c | 32 ++++++++++++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 35db949..22f351c 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -1388,6 +1388,37 @@ static bool version_before_3(void *opaque, int version_id) > return version_id < 3; > } > > +static bool spapr_ccs_list_needed(void *opaque) > +{ > + sPAPRMachineState *spapr = (sPAPRMachineState *)opaque; > + return !QTAILQ_EMPTY(&spapr->ccs_list); > +} > + > +static const VMStateDescription vmstate_spapr_ccs = { > + .name = "spaprconfigureconnectorstate", some word separators wouldn't hurt, since they might show up in migration error messages. > + .version_id = 1, > + .minimum_version_id = 1, > + .fields = (VMStateField[]) { > + VMSTATE_UINT32(drc_index, sPAPRConfigureConnectorState), > + VMSTATE_INT32(fdt_offset, sPAPRConfigureConnectorState), > + VMSTATE_INT32(fdt_depth, sPAPRConfigureConnectorState), > + VMSTATE_END_OF_LIST() > + }, > +}; > + > +static const VMStateDescription vmstate_spapr_ccs_list = { > + .name = "spaprccslist", > + .version_id = 1, > + .minimum_version_id = 1, > + .needed = spapr_ccs_list_needed, > + .fields = (VMStateField[]) { > + VMSTATE_QTAILQ_V(ccs_list, sPAPRMachineState, 1, > + vmstate_spapr_ccs, sPAPRConfigureConnectorState, > + next), > + VMSTATE_END_OF_LIST() > + }, > +}; > + > static bool spapr_ov5_cas_needed(void *opaque) > { > sPAPRMachineState *spapr = opaque; > @@ -1486,6 +1517,7 @@ static const VMStateDescription vmstate_spapr = { > .subsections = (const VMStateDescription*[]) { > &vmstate_spapr_ov5_cas, > &vmstate_spapr_patb_entry, > + &vmstate_spapr_ccs_list, > NULL > } > }; > -- > 2.9.3 > >
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 35db949..22f351c 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -1388,6 +1388,37 @@ static bool version_before_3(void *opaque, int version_id) return version_id < 3; } +static bool spapr_ccs_list_needed(void *opaque) +{ + sPAPRMachineState *spapr = (sPAPRMachineState *)opaque; + return !QTAILQ_EMPTY(&spapr->ccs_list); +} + +static const VMStateDescription vmstate_spapr_ccs = { + .name = "spaprconfigureconnectorstate", + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_UINT32(drc_index, sPAPRConfigureConnectorState), + VMSTATE_INT32(fdt_offset, sPAPRConfigureConnectorState), + VMSTATE_INT32(fdt_depth, sPAPRConfigureConnectorState), + VMSTATE_END_OF_LIST() + }, +}; + +static const VMStateDescription vmstate_spapr_ccs_list = { + .name = "spaprccslist", + .version_id = 1, + .minimum_version_id = 1, + .needed = spapr_ccs_list_needed, + .fields = (VMStateField[]) { + VMSTATE_QTAILQ_V(ccs_list, sPAPRMachineState, 1, + vmstate_spapr_ccs, sPAPRConfigureConnectorState, + next), + VMSTATE_END_OF_LIST() + }, +}; + static bool spapr_ov5_cas_needed(void *opaque) { sPAPRMachineState *spapr = opaque; @@ -1486,6 +1517,7 @@ static const VMStateDescription vmstate_spapr = { .subsections = (const VMStateDescription*[]) { &vmstate_spapr_ov5_cas, &vmstate_spapr_patb_entry, + &vmstate_spapr_ccs_list, NULL } };