migration: Hack to maintain backwards compatibility for ppc

Current code does:
- register pre_2_10_vmstate_dummy_icp with "icp/server" and instance
  dependinfg on cpu number
- for newer machines, it register vmstate_icp with "icp/server" name
  and instance 0
- now it unregisters "icp/server" for the 1st instance.

This is wrong at many levels:
- we shouldn't have two VMSTATEDescriptions with the same name
- In case this is the only solution that we can came with, it needs to
  be:
  * register pre_2_10_vmstate_dummy_icp
  * unregister pre_2_10_vmstate_dummy_icp
  * register real vmstate_icp

Created vmstate_replace_hack_for_ppc() with warnings left and right
that it is a hack.

CC: Cedric Le Goater <clg@kaod.org>
CC: Daniel Henrique Barboza <danielhb413@gmail.com>
CC: David Gibson <david@gibson.dropbear.id.au>
CC: Greg Kurz <groug@kaod.org>

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231020090731.28701-8-quintela@redhat.com>
This commit is contained in:
Juan Quintela 2023-10-20 11:07:25 +02:00
parent b23db4cd82
commit 485fb95546
4 changed files with 68 additions and 4 deletions

View File

@ -335,8 +335,22 @@ static void icp_realize(DeviceState *dev, Error **errp)
return;
}
}
vmstate_register(NULL, icp->cs->cpu_index, &vmstate_icp_server, icp);
/*
* The way that pre_2_10_icp is handling is really, really hacky.
* We used to have here this call:
*
* vmstate_register(NULL, icp->cs->cpu_index, &vmstate_icp_server, icp);
*
* But we were doing:
* pre_2_10_vmstate_register_dummy_icp()
* this vmstate_register()
* pre_2_10_vmstate_unregister_dummy_icp()
*
* So for a short amount of time we had to vmstate entries with
* the same name. This fixes it.
*/
vmstate_replace_hack_for_ppc(NULL, icp->cs->cpu_index,
&vmstate_icp_server, icp);
}
static void icp_unrealize(DeviceState *dev)

View File

@ -143,6 +143,11 @@ static bool pre_2_10_vmstate_dummy_icp_needed(void *opaque)
}
static const VMStateDescription pre_2_10_vmstate_dummy_icp = {
/*
* Hack ahead. We can't have two devices with the same name and
* instance id. So I rename this to pass make check.
* Real help from people who knows the hardware is needed.
*/
.name = "icp/server",
.version_id = 1,
.minimum_version_id = 1,
@ -155,16 +160,32 @@ static const VMStateDescription pre_2_10_vmstate_dummy_icp = {
},
};
/*
* See comment in hw/intc/xics.c:icp_realize()
*
* You have to remove vmstate_replace_hack_for_ppc() when you remove
* the machine types that need the following function.
*/
static void pre_2_10_vmstate_register_dummy_icp(int i)
{
vmstate_register(NULL, i, &pre_2_10_vmstate_dummy_icp,
(void *)(uintptr_t) i);
}
/*
* See comment in hw/intc/xics.c:icp_realize()
*
* You have to remove vmstate_replace_hack_for_ppc() when you remove
* the machine types that need the following function.
*/
static void pre_2_10_vmstate_unregister_dummy_icp(int i)
{
vmstate_unregister(NULL, &pre_2_10_vmstate_dummy_icp,
(void *)(uintptr_t) i);
/*
* This used to be:
*
* vmstate_unregister(NULL, &pre_2_10_vmstate_dummy_icp,
* (void *)(uintptr_t) i);
*/
}
int spapr_max_server_number(SpaprMachineState *spapr)

View File

@ -1230,6 +1230,17 @@ static inline int vmstate_register(VMStateIf *obj, int instance_id,
opaque, -1, 0, NULL);
}
/**
* vmstate_replace_hack_for_ppc() - ppc used to abuse vmstate_register
*
* Don't even think about using this function in new code.
*
* Returns: 0 on success, -1 on failure
*/
int vmstate_replace_hack_for_ppc(VMStateIf *obj, int instance_id,
const VMStateDescription *vmsd,
void *opaque);
/**
* vmstate_register_any() - legacy function to register state
* serialisation description and let the function choose the id

View File

@ -846,6 +846,24 @@ static void vmstate_check(const VMStateDescription *vmsd)
}
}
/*
* See comment in hw/intc/xics.c:icp_realize()
*
* This function can be removed when
* pre_2_10_vmstate_register_dummy_icp() is removed.
*/
int vmstate_replace_hack_for_ppc(VMStateIf *obj, int instance_id,
const VMStateDescription *vmsd,
void *opaque)
{
SaveStateEntry *se = find_se(vmsd->name, instance_id);
if (se) {
savevm_state_handler_remove(se);
}
return vmstate_register(obj, instance_id, vmsd, opaque);
}
int vmstate_register_with_alias_id(VMStateIf *obj, uint32_t instance_id,
const VMStateDescription *vmsd,
void *opaque, int alias_id,