qemu/include/hw/s390x/storage-keys.h
David Hildenbrand c35622387e hw/s390x/s390-skeys: lazy storage key enablement under TCG
Let's enable storage keys lazily under TCG, just as we do under KVM.
Only fairly old Linux versions actually make use of storage keys, so it
can be kind of wasteful to allocate quite some memory and track
changes and references if nobody cares.

We have to make sure to flush the TLB when enabling storage keys after
the VM was already running: otherwise it might happen that we don't
catch references or modifications afterwards.

Add proper documentation to all callbacks.

The kvm-unit-tests skey tests keeps on working with this change.

Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210903155514.44772-14-david@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2021-09-06 16:24:05 +02:00

121 lines
3.6 KiB
C

/*
* s390 storage key device
*
* Copyright 2015 IBM Corp.
* Author(s): Jason J. Herne <jjherne@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#ifndef S390_STORAGE_KEYS_H
#define S390_STORAGE_KEYS_H
#include "hw/qdev-core.h"
#include "monitor/monitor.h"
#include "qom/object.h"
#define TYPE_S390_SKEYS "s390-skeys"
OBJECT_DECLARE_TYPE(S390SKeysState, S390SKeysClass, S390_SKEYS)
struct S390SKeysState {
DeviceState parent_obj;
bool migration_enabled;
};
struct S390SKeysClass {
DeviceClass parent_class;
/**
* @skeys_are_enabled:
*
* Check whether storage keys are enabled. If not enabled, they were not
* enabled lazily either by the guest via a storage key instruction or
* by the host during migration.
*
* If disabled, everything not explicitly triggered by the guest,
* such as outgoing migration or dirty/change tracking, should not touch
* storage keys and should not lazily enable it.
*
* @ks: the #S390SKeysState
*
* Returns false if not enabled and true if enabled.
*/
bool (*skeys_are_enabled)(S390SKeysState *ks);
/**
* @enable_skeys:
*
* Lazily enable storage keys. If this function is not implemented,
* setting a storage key will lazily enable storage keys implicitly
* instead. TCG guests have to make sure to flush the TLB of all CPUs
* if storage keys were not enabled before this call.
*
* @ks: the #S390SKeysState
*
* Returns false if not enabled before this call, and true if already
* enabled.
*/
bool (*enable_skeys)(S390SKeysState *ks);
/**
* @get_skeys:
*
* Get storage keys for the given PFN range. This call will fail if
* storage keys have not been lazily enabled yet.
*
* Callers have to validate that a GFN is valid before this call.
*
* @ks: the #S390SKeysState
* @start_gfn: the start GFN to get storage keys for
* @count: the number of storage keys to get
* @keys: the byte array where storage keys will be stored to
*
* Returns 0 on success, returns an error if getting a storage key failed.
*/
int (*get_skeys)(S390SKeysState *ks, uint64_t start_gfn, uint64_t count,
uint8_t *keys);
/**
* @set_skeys:
*
* Set storage keys for the given PFN range. This call will fail if
* storage keys have not been lazily enabled yet and implicit
* enablement is not supported.
*
* Callers have to validate that a GFN is valid before this call.
*
* @ks: the #S390SKeysState
* @start_gfn: the start GFN to set storage keys for
* @count: the number of storage keys to set
* @keys: the byte array where storage keys will be read from
*
* Returns 0 on success, returns an error if setting a storage key failed.
*/
int (*set_skeys)(S390SKeysState *ks, uint64_t start_gfn, uint64_t count,
uint8_t *keys);
};
#define TYPE_KVM_S390_SKEYS "s390-skeys-kvm"
#define TYPE_QEMU_S390_SKEYS "s390-skeys-qemu"
typedef struct QEMUS390SKeysState QEMUS390SKeysState;
DECLARE_INSTANCE_CHECKER(QEMUS390SKeysState, QEMU_S390_SKEYS,
TYPE_QEMU_S390_SKEYS)
struct QEMUS390SKeysState {
S390SKeysState parent_obj;
uint8_t *keydata;
uint32_t key_count;
};
void s390_skeys_init(void);
S390SKeysState *s390_get_skeys_device(void);
void hmp_dump_skeys(Monitor *mon, const QDict *qdict);
void hmp_info_skeys(Monitor *mon, const QDict *qdict);
#endif /* S390_STORAGE_KEYS_H */