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KVM: s390: Create ioctl for Getting/Setting guest storage keys

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Provide the KVM_S390_GET_SKEYS and KVM_S390_SET_SKEYS ioctl which can be used
to get/set guest storage keys. This functionality is needed for live migration
of s390 guests that use storage keys.

Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
tirimbino
Jason J. Herne 11 years ago committed by Christian Borntraeger
parent e44fc8c9da
commit 30ee2a984f
3 changed files with 195 additions and 0 deletions
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  1. 58
      Documentation/virtual/kvm/api.txt
  2. 123
      arch/s390/kvm/kvm-s390.c
  3. 14
      include/uapi/linux/kvm.h

58
Documentation/virtual/kvm/api.txt
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@ -2762,6 +2762,64 @@ register number to be used.
The "reserved" field is meant for future extensions. It is not used by
KVM with the currently defined set of flags.
4.90 KVM_S390_GET_SKEYS
Capability: KVM_CAP_S390_SKEYS
Architectures: s390
Type: vm ioctl
Parameters: struct kvm_s390_skeys
Returns: 0 on success, KVM_S390_GET_KEYS_NONE if guest is not using storage
keys, negative value on error
This ioctl is used to get guest storage key values on the s390
architecture. The ioctl takes parameters via the kvm_s390_skeys struct.
struct kvm_s390_skeys {
__u64 start_gfn;
__u64 count;
__u64 skeydata_addr;
__u32 flags;
__u32 reserved[9];
};
The start_gfn field is the number of the first guest frame whose storage keys
you want to get.
The count field is the number of consecutive frames (starting from start_gfn)
whose storage keys to get. The count field must be at least 1 and the maximum
allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range
will cause the ioctl to return -EINVAL.
The skeydata_addr field is the address to a buffer large enough to hold count
bytes. This buffer will be filled with storage key data by the ioctl.
4.91 KVM_S390_SET_SKEYS
Capability: KVM_CAP_S390_SKEYS
Architectures: s390
Type: vm ioctl
Parameters: struct kvm_s390_skeys
Returns: 0 on success, negative value on error
This ioctl is used to set guest storage key values on the s390
architecture. The ioctl takes parameters via the kvm_s390_skeys struct.
See section on KVM_S390_GET_SKEYS for struct definition.
The start_gfn field is the number of the first guest frame whose storage keys
you want to set.
The count field is the number of consecutive frames (starting from start_gfn)
whose storage keys to get. The count field must be at least 1 and the maximum
allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range
will cause the ioctl to return -EINVAL.
The skeydata_addr field is the address to a buffer containing count bytes of
storage keys. Each byte in the buffer will be set as the storage key for a
single frame starting at start_gfn for count frames.
Note: If any architecturally invalid key value is found in the given data then
the ioctl will return -EINVAL.
5. The kvm_run structure
------------------------

123
arch/s390/kvm/kvm-s390.c
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@ -179,6 +179,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_MP_STATE:
case KVM_CAP_S390_USER_SIGP:
case KVM_CAP_S390_USER_STSI:
case KVM_CAP_S390_SKEYS:
r = 1;
break;
case KVM_CAP_S390_MEM_OP:
@ -729,6 +730,108 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
return ret;
}
static long kvm_s390_get_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
{
uint8_t *keys;
uint64_t hva;
unsigned long curkey;
int i, r = 0;
if (args->flags != 0)
return -EINVAL;
/* Is this guest using storage keys? */
if (!mm_use_skey(current->mm))
return KVM_S390_GET_SKEYS_NONE;
/* Enforce sane limit on memory allocation */
if (args->count < 1 || args->count > KVM_S390_SKEYS_MAX)
return -EINVAL;
keys = kmalloc_array(args->count, sizeof(uint8_t),
GFP_KERNEL | __GFP_NOWARN);
if (!keys)
keys = vmalloc(sizeof(uint8_t) * args->count);
if (!keys)
return -ENOMEM;
for (i = 0; i < args->count; i++) {
hva = gfn_to_hva(kvm, args->start_gfn + i);
if (kvm_is_error_hva(hva)) {
r = -EFAULT;
goto out;
}
curkey = get_guest_storage_key(current->mm, hva);
if (IS_ERR_VALUE(curkey)) {
r = curkey;
goto out;
}
keys[i] = curkey;
}
r = copy_to_user((uint8_t __user *)args->skeydata_addr, keys,
sizeof(uint8_t) * args->count);
if (r)
r = -EFAULT;
out:
kvfree(keys);
return r;
}
static long kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
{
uint8_t *keys;
uint64_t hva;
int i, r = 0;
if (args->flags != 0)
return -EINVAL;
/* Enforce sane limit on memory allocation */
if (args->count < 1 || args->count > KVM_S390_SKEYS_MAX)
return -EINVAL;
keys = kmalloc_array(args->count, sizeof(uint8_t),
GFP_KERNEL | __GFP_NOWARN);
if (!keys)
keys = vmalloc(sizeof(uint8_t) * args->count);
if (!keys)
return -ENOMEM;
r = copy_from_user(keys, (uint8_t __user *)args->skeydata_addr,
sizeof(uint8_t) * args->count);
if (r) {
r = -EFAULT;
goto out;
}
/* Enable storage key handling for the guest */
s390_enable_skey();
for (i = 0; i < args->count; i++) {
hva = gfn_to_hva(kvm, args->start_gfn + i);
if (kvm_is_error_hva(hva)) {
r = -EFAULT;
goto out;
}
/* Lowest order bit is reserved */
if (keys[i] & 0x01) {
r = -EINVAL;
goto out;
}
r = set_guest_storage_key(current->mm, hva,
(unsigned long)keys[i], 0);
if (r)
goto out;
}
out:
kvfree(keys);
return r;
}
long kvm_arch_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@ -788,6 +891,26 @@ long kvm_arch_vm_ioctl(struct file *filp,
r = kvm_s390_vm_has_attr(kvm, &attr);
break;
}
case KVM_S390_GET_SKEYS: {
struct kvm_s390_skeys args;
r = -EFAULT;
if (copy_from_user(&args, argp,
sizeof(struct kvm_s390_skeys)))
break;
r = kvm_s390_get_skeys(kvm, &args);
break;
}
case KVM_S390_SET_SKEYS: {
struct kvm_s390_skeys args;
r = -EFAULT;
if (copy_from_user(&args, argp,
sizeof(struct kvm_s390_skeys)))
break;
r = kvm_s390_set_skeys(kvm, &args);
break;
}
default:
r = -ENOTTY;
}

14
include/uapi/linux/kvm.h
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@ -147,6 +147,16 @@ struct kvm_pit_config {
#define KVM_PIT_SPEAKER_DUMMY 1
struct kvm_s390_skeys {
__u64 start_gfn;
__u64 count;
__u64 skeydata_addr;
__u32 flags;
__u32 reserved[9];
};
#define KVM_S390_GET_SKEYS_NONE 1
#define KVM_S390_SKEYS_MAX 1048576
#define KVM_EXIT_UNKNOWN 0
#define KVM_EXIT_EXCEPTION 1
#define KVM_EXIT_IO 2
@ -791,6 +801,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_S390_VECTOR_REGISTERS 107
#define KVM_CAP_S390_MEM_OP 108
#define KVM_CAP_S390_USER_STSI 109
#define KVM_CAP_S390_SKEYS 110
#ifdef KVM_CAP_IRQ_ROUTING
@ -1168,6 +1179,9 @@ struct kvm_s390_ucas_mapping {
#define KVM_GET_REG_LIST _IOWR(KVMIO, 0xb0, struct kvm_reg_list)
/* Available with KVM_CAP_S390_MEM_OP */
#define KVM_S390_MEM_OP _IOW(KVMIO, 0xb1, struct kvm_s390_mem_op)
/* Available with KVM_CAP_S390_SKEYS */
#define KVM_S390_GET_SKEYS _IOW(KVMIO, 0xb2, struct kvm_s390_skeys)
#define KVM_S390_SET_SKEYS _IOW(KVMIO, 0xb3, struct kvm_s390_skeys)
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
#define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1)

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