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| author | Collin L. Walling <walling@linux.vnet.ibm.com> | 2016-07-26 21:29:44 +0200 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2017-08-29 15:15:54 +0200 |
| commit | 8fa1696ea78162ca3112a26879d9379483443c85 (patch) | |
| tree | 3930f3b5b7b71e39dd8117c87704392b7badc840 /Documentation/virtual/kvm/devices/vm.txt | |
| parent | KVM: s390: Support Configuration z/Architecture Mode (diff) | |
| download | linux-8fa1696ea78162ca3112a26879d9379483443c85.tar.xz linux-8fa1696ea78162ca3112a26879d9379483443c85.zip | |
KVM: s390: Multiple Epoch Facility support
Allow for the enablement of MEF and the support for the extended
epoch in SIE and VSIE for the extended guest TOD-Clock.
A new interface is used for getting/setting a guest's extended TOD-Clock
that uses a single ioctl invocation, KVM_S390_VM_TOD_EXT. Since the
host time is a moving target that might see an epoch switch or STP sync
checks we need an atomic ioctl and cannot use the exisiting two
interfaces. The old method of getting and setting the guest TOD-Clock is
still retained and is used when the old ioctls are called.
Signed-off-by: Collin L. Walling <walling@linux.vnet.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'Documentation/virtual/kvm/devices/vm.txt')
| -rw-r--r-- | Documentation/virtual/kvm/devices/vm.txt | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt index 903fc926860b..95ca68d663a4 100644 --- a/Documentation/virtual/kvm/devices/vm.txt +++ b/Documentation/virtual/kvm/devices/vm.txt @@ -176,7 +176,8 @@ Architectures: s390 3.1. ATTRIBUTE: KVM_S390_VM_TOD_HIGH -Allows user space to set/get the TOD clock extension (u8). +Allows user space to set/get the TOD clock extension (u8) (superseded by +KVM_S390_VM_TOD_EXT). Parameters: address of a buffer in user space to store the data (u8) to Returns: -EFAULT if the given address is not accessible from kernel space @@ -190,6 +191,17 @@ the POP (u64). Parameters: address of a buffer in user space to store the data (u64) to Returns: -EFAULT if the given address is not accessible from kernel space +3.3. ATTRIBUTE: KVM_S390_VM_TOD_EXT +Allows user space to set/get bits 0-63 of the TOD clock register as defined in +the POP (u64). If the guest CPU model supports the TOD clock extension (u8), it +also allows user space to get/set it. If the guest CPU model does not support +it, it is stored as 0 and not allowed to be set to a value != 0. + +Parameters: address of a buffer in user space to store the data + (kvm_s390_vm_tod_clock) to +Returns: -EFAULT if the given address is not accessible from kernel space + -EINVAL if setting the TOD clock extension to != 0 is not supported + 4. GROUP: KVM_S390_VM_CRYPTO Architectures: s390 |