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qemu/include/hw/ppc/spapr_drc.h
Daniel Henrique Barboza 10f12e6450 hw/ppc: CAS reset on early device hotplug 
This patch is a follow up on the discussions made in patch
"hw/ppc: disable hotplug before CAS is completed" that can be
found at [1].

At this moment, we do not support CPU/memory hotplug in early
boot stages, before CAS. When a hotplug occurs, the event is logged
in an internal RTAS event log queue and an IRQ pulse is fired. In
regular conditions, the guest handles the interrupt by executing
check_exception, fetching the generated hotplug event and enabling
the device for use.

In early boot, this IRQ isn't caught (SLOF does not handle hotplug
events), leaving the event in the rtas event log queue. If the guest
executes check_exception due to another hotplug event, the re-assertion
of the IRQ ends up de-queuing the first hotplug event as well. In short,
a device hotplugged before CAS is considered coldplugged by SLOF.
This leads to device misbehavior and, in some cases, guest kernel
Ooops when trying to unplug the device.

A proper fix would be to turn every device hotplugged before CAS
as a colplugged device. This is not trivial to do with the current
code base though - the FDT is written in the guest memory at
ppc_spapr_reset and can't be retrieved without adding extra state
(fdt_size for example) that will need to managed and migrated. Adding
the hotplugged DT in the middle of CAS negotiation via the updated DT
tree works with CPU devs, but panics the guest kernel at boot. Additional
analysis would be necessary for LMBs and PCI devices. There are
questions to be made in QEMU/SLOF/kernel level about how we can make
this change in a sustainable way.

With Linux guests, a fix would be the kernel executing check_exception
at boot time, de-queueing the events that happened in early boot and
processing them. However, even if/when the newer kernels start
fetching these events at boot time, we need to take care of older
kernels that won't be doing that.

This patch works around the situation by issuing a CAS reset if a hotplugged
device is detected during CAS:

- the DRC conditions that warrant a CAS reset is the same as those that
triggers a DRC migration - the DRC must have a device attached and
the DRC state is not equal to its ready_state. With that in mind, this
patch makes use of 'spapr_drc_needed' to determine if a CAS reset
is needed.

- In the middle of CAS negotiations, the function
'spapr_hotplugged_dev_before_cas' goes through all the DRCs to see
if there are any DRC that requires a reset, using spapr_drc_needed. If
that happens, returns '1' in 'spapr_h_cas_compose_response' which will set
spapr->cas_reboot to true, causing the machine to reboot.

No changes are made for coldplug devices.

[1] http://lists.nongnu.org/archive/html/qemu-devel/2017-08/msg02855.html

Signed-off-by: Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2017-09-08 09:30:54 +10:00

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/*
* QEMU SPAPR Dynamic Reconfiguration Connector Implementation
*
* Copyright IBM Corp. 2014
*
* Authors:
* Michael Roth <mdroth@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef HW_SPAPR_DRC_H
#define HW_SPAPR_DRC_H
#include <libfdt.h>
#include "qom/object.h"
#include "sysemu/sysemu.h"
#include "hw/qdev.h"
#define TYPE_SPAPR_DR_CONNECTOR "spapr-dr-connector"
#define SPAPR_DR_CONNECTOR_GET_CLASS(obj) \
OBJECT_GET_CLASS(sPAPRDRConnectorClass, obj, TYPE_SPAPR_DR_CONNECTOR)
#define SPAPR_DR_CONNECTOR_CLASS(klass) \
OBJECT_CLASS_CHECK(sPAPRDRConnectorClass, klass, \
TYPE_SPAPR_DR_CONNECTOR)
#define SPAPR_DR_CONNECTOR(obj) OBJECT_CHECK(sPAPRDRConnector, (obj), \
TYPE_SPAPR_DR_CONNECTOR)
#define TYPE_SPAPR_DRC_PHYSICAL "spapr-drc-physical"
#define SPAPR_DRC_PHYSICAL_GET_CLASS(obj) \
OBJECT_GET_CLASS(sPAPRDRConnectorClass, obj, TYPE_SPAPR_DRC_PHYSICAL)
#define SPAPR_DRC_PHYSICAL_CLASS(klass) \
OBJECT_CLASS_CHECK(sPAPRDRConnectorClass, klass, \
TYPE_SPAPR_DRC_PHYSICAL)
#define SPAPR_DRC_PHYSICAL(obj) OBJECT_CHECK(sPAPRDRCPhysical, (obj), \
TYPE_SPAPR_DRC_PHYSICAL)
#define TYPE_SPAPR_DRC_LOGICAL "spapr-drc-logical"
#define SPAPR_DRC_LOGICAL_GET_CLASS(obj) \
OBJECT_GET_CLASS(sPAPRDRConnectorClass, obj, TYPE_SPAPR_DRC_LOGICAL)
#define SPAPR_DRC_LOGICAL_CLASS(klass) \
OBJECT_CLASS_CHECK(sPAPRDRConnectorClass, klass, \
TYPE_SPAPR_DRC_LOGICAL)
#define SPAPR_DRC_LOGICAL(obj) OBJECT_CHECK(sPAPRDRConnector, (obj), \
TYPE_SPAPR_DRC_LOGICAL)
#define TYPE_SPAPR_DRC_CPU "spapr-drc-cpu"
#define SPAPR_DRC_CPU_GET_CLASS(obj) \
OBJECT_GET_CLASS(sPAPRDRConnectorClass, obj, TYPE_SPAPR_DRC_CPU)
#define SPAPR_DRC_CPU_CLASS(klass) \
OBJECT_CLASS_CHECK(sPAPRDRConnectorClass, klass, TYPE_SPAPR_DRC_CPU)
#define SPAPR_DRC_CPU(obj) OBJECT_CHECK(sPAPRDRConnector, (obj), \
TYPE_SPAPR_DRC_CPU)
#define TYPE_SPAPR_DRC_PCI "spapr-drc-pci"
#define SPAPR_DRC_PCI_GET_CLASS(obj) \
OBJECT_GET_CLASS(sPAPRDRConnectorClass, obj, TYPE_SPAPR_DRC_PCI)
#define SPAPR_DRC_PCI_CLASS(klass) \
OBJECT_CLASS_CHECK(sPAPRDRConnectorClass, klass, TYPE_SPAPR_DRC_PCI)
#define SPAPR_DRC_PCI(obj) OBJECT_CHECK(sPAPRDRConnector, (obj), \
TYPE_SPAPR_DRC_PCI)
#define TYPE_SPAPR_DRC_LMB "spapr-drc-lmb"
#define SPAPR_DRC_LMB_GET_CLASS(obj) \
OBJECT_GET_CLASS(sPAPRDRConnectorClass, obj, TYPE_SPAPR_DRC_LMB)
#define SPAPR_DRC_LMB_CLASS(klass) \
OBJECT_CLASS_CHECK(sPAPRDRConnectorClass, klass, TYPE_SPAPR_DRC_LMB)
#define SPAPR_DRC_LMB(obj) OBJECT_CHECK(sPAPRDRConnector, (obj), \
TYPE_SPAPR_DRC_LMB)
/*
* Various hotplug types managed by sPAPRDRConnector
*
* these are somewhat arbitrary, but to make things easier
* when generating DRC indexes later we've aligned the bit
* positions with the values used to assign DRC indexes on
* pSeries. we use those values as bit shifts to allow for
* the OR'ing of these values in various QEMU routines, but
* for values exposed to the guest (via DRC indexes for
* instance) we will use the shift amounts.
*/
typedef enum {
SPAPR_DR_CONNECTOR_TYPE_SHIFT_CPU = 1,
SPAPR_DR_CONNECTOR_TYPE_SHIFT_PHB = 2,
SPAPR_DR_CONNECTOR_TYPE_SHIFT_VIO = 3,
SPAPR_DR_CONNECTOR_TYPE_SHIFT_PCI = 4,
SPAPR_DR_CONNECTOR_TYPE_SHIFT_LMB = 8,
} sPAPRDRConnectorTypeShift;
typedef enum {
SPAPR_DR_CONNECTOR_TYPE_ANY = ~0,
SPAPR_DR_CONNECTOR_TYPE_CPU = 1 << SPAPR_DR_CONNECTOR_TYPE_SHIFT_CPU,
SPAPR_DR_CONNECTOR_TYPE_PHB = 1 << SPAPR_DR_CONNECTOR_TYPE_SHIFT_PHB,
SPAPR_DR_CONNECTOR_TYPE_VIO = 1 << SPAPR_DR_CONNECTOR_TYPE_SHIFT_VIO,
SPAPR_DR_CONNECTOR_TYPE_PCI = 1 << SPAPR_DR_CONNECTOR_TYPE_SHIFT_PCI,
SPAPR_DR_CONNECTOR_TYPE_LMB = 1 << SPAPR_DR_CONNECTOR_TYPE_SHIFT_LMB,
} sPAPRDRConnectorType;
/*
* set via set-indicator RTAS calls
* as documented by PAPR+ 2.7 13.5.3.4, Table 177
*
* isolated: put device under firmware control
* unisolated: claim OS control of device (may or may not be in use)
*/
typedef enum {
SPAPR_DR_ISOLATION_STATE_ISOLATED = 0,
SPAPR_DR_ISOLATION_STATE_UNISOLATED = 1
} sPAPRDRIsolationState;
/*
* set via set-indicator RTAS calls
* as documented by PAPR+ 2.7 13.5.3.4, Table 177
*
* unusable: mark device as unavailable to OS
* usable: mark device as available to OS
* exchange: (currently unused)
* recover: (currently unused)
*/
typedef enum {
SPAPR_DR_ALLOCATION_STATE_UNUSABLE = 0,
SPAPR_DR_ALLOCATION_STATE_USABLE = 1,
SPAPR_DR_ALLOCATION_STATE_EXCHANGE = 2,
SPAPR_DR_ALLOCATION_STATE_RECOVER = 3
} sPAPRDRAllocationState;
/*
* DR-indicator (LED/visual indicator)
*
* set via set-indicator RTAS calls
* as documented by PAPR+ 2.7 13.5.3.4, Table 177,
* and PAPR+ 2.7 13.5.4.1, Table 180
*
* inactive: hotpluggable entity inactive and safely removable
* active: hotpluggable entity in use and not safely removable
* identify: (currently unused)
* action: (currently unused)
*/
typedef enum {
SPAPR_DR_INDICATOR_INACTIVE = 0,
SPAPR_DR_INDICATOR_ACTIVE = 1,
SPAPR_DR_INDICATOR_IDENTIFY = 2,
SPAPR_DR_INDICATOR_ACTION = 3,
} sPAPRDRIndicatorState;
/*
* returned via get-sensor-state RTAS calls
* as documented by PAPR+ 2.7 13.5.3.3, Table 175:
*
* empty: connector slot empty (e.g. empty hotpluggable PCI slot)
* present: connector slot populated and device available to OS
* unusable: device not currently available to OS
* exchange: (currently unused)
* recover: (currently unused)
*/
typedef enum {
SPAPR_DR_ENTITY_SENSE_EMPTY = 0,
SPAPR_DR_ENTITY_SENSE_PRESENT = 1,
SPAPR_DR_ENTITY_SENSE_UNUSABLE = 2,
SPAPR_DR_ENTITY_SENSE_EXCHANGE = 3,
SPAPR_DR_ENTITY_SENSE_RECOVER = 4,
} sPAPRDREntitySense;
typedef enum {
SPAPR_DR_CC_RESPONSE_NEXT_SIB = 1, /* currently unused */
SPAPR_DR_CC_RESPONSE_NEXT_CHILD = 2,
SPAPR_DR_CC_RESPONSE_NEXT_PROPERTY = 3,
SPAPR_DR_CC_RESPONSE_PREV_PARENT = 4,
SPAPR_DR_CC_RESPONSE_SUCCESS = 0,
SPAPR_DR_CC_RESPONSE_ERROR = -1,
SPAPR_DR_CC_RESPONSE_CONTINUE = -2,
SPAPR_DR_CC_RESPONSE_NOT_CONFIGURABLE = -9003,
} sPAPRDRCCResponse;
typedef enum {
/*
* Values come from Fig. 12 in LoPAPR section 13.4
*
* These are exposed in the migration stream, so don't change
* them.
*/
SPAPR_DRC_STATE_INVALID = 0,
SPAPR_DRC_STATE_LOGICAL_UNUSABLE = 1,
SPAPR_DRC_STATE_LOGICAL_AVAILABLE = 2,
SPAPR_DRC_STATE_LOGICAL_UNISOLATE = 3,
SPAPR_DRC_STATE_LOGICAL_CONFIGURED = 4,
SPAPR_DRC_STATE_PHYSICAL_AVAILABLE = 5,
SPAPR_DRC_STATE_PHYSICAL_POWERON = 6,
SPAPR_DRC_STATE_PHYSICAL_UNISOLATE = 7,
SPAPR_DRC_STATE_PHYSICAL_CONFIGURED = 8,
} sPAPRDRCState;
typedef struct sPAPRDRConnector {
/*< private >*/
DeviceState parent;
uint32_t id;
Object *owner;
uint32_t state;
/* RTAS ibm,configure-connector state */
/* (only valid in UNISOLATE state) */
int ccs_offset;
int ccs_depth;
/* device pointer, via link property */
DeviceState *dev;
bool unplug_requested;
void *fdt;
int fdt_start_offset;
} sPAPRDRConnector;
typedef struct sPAPRDRConnectorClass {
/*< private >*/
DeviceClass parent;
sPAPRDRCState empty_state;
sPAPRDRCState ready_state;
/*< public >*/
sPAPRDRConnectorTypeShift typeshift;
const char *typename; /* used in device tree, PAPR 13.5.2.6 & C.6.1 */
const char *drc_name_prefix; /* used other places in device tree */
sPAPRDREntitySense (*dr_entity_sense)(sPAPRDRConnector *drc);
uint32_t (*isolate)(sPAPRDRConnector *drc);
uint32_t (*unisolate)(sPAPRDRConnector *drc);
void (*release)(DeviceState *dev);
} sPAPRDRConnectorClass;
typedef struct sPAPRDRCPhysical {
/*< private >*/
sPAPRDRConnector parent;
/* DR-indicator */
uint32_t dr_indicator;
} sPAPRDRCPhysical;
static inline bool spapr_drc_hotplugged(DeviceState *dev)
{
return dev->hotplugged && !runstate_check(RUN_STATE_INMIGRATE);
}
void spapr_drc_reset(sPAPRDRConnector *drc);
uint32_t spapr_drc_index(sPAPRDRConnector *drc);
sPAPRDRConnectorType spapr_drc_type(sPAPRDRConnector *drc);
sPAPRDRConnector *spapr_dr_connector_new(Object *owner, const char *type,
uint32_t id);
sPAPRDRConnector *spapr_drc_by_index(uint32_t index);
sPAPRDRConnector *spapr_drc_by_id(const char *type, uint32_t id);
int spapr_drc_populate_dt(void *fdt, int fdt_offset, Object *owner,
uint32_t drc_type_mask);
void spapr_drc_attach(sPAPRDRConnector *drc, DeviceState *d, void *fdt,
int fdt_start_offset, Error **errp);
void spapr_drc_detach(sPAPRDRConnector *drc);
bool spapr_drc_needed(void *opaque);
static inline bool spapr_drc_unplug_requested(sPAPRDRConnector *drc)
{
return drc->unplug_requested;
}
#endif /* HW_SPAPR_DRC_H */
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