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| author | Pierre Morel <pmorel@linux.ibm.com> | 2022-07-14 21:43:34 +0200 |
|---|---|---|
| committer | Janosch Frank <frankja@linux.ibm.com> | 2022-07-20 10:57:37 +0200 |
| commit | f5ecfee94493475783074e86ded10a0499d779fc (patch) | |
| tree | 996d75fb3e60b1c3230ee472148703f87a938605 /Documentation/virt | |
| parent | 24fe0195bc19306b2769b43b3e22bd35bd6fb061 (diff) | |
| download | linux-f5ecfee94493475783074e86ded10a0499d779fc.tar.gz | |
KVM: s390: resetting the Topology-Change-Report
During a subsystem reset the Topology-Change-Report is cleared.
Let's give userland the possibility to clear the MTCR in the case
of a subsystem reset.
To migrate the MTCR, we give userland the possibility to
query the MTCR state.
We indicate KVM support for the CPU topology facility with a new
KVM capability: KVM_CAP_S390_CPU_TOPOLOGY.
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20220714194334.127812-1-pmorel@linux.ibm.com>
Link: https://lore.kernel.org/all/20220714194334.127812-1-pmorel@linux.ibm.com/
[frankja@linux.ibm.com: Simple conflict resolution in Documentation/virt/kvm/api.rst]
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Diffstat (limited to 'Documentation/virt')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 5be5cc59869d19..3c4551a2f6d00b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -8269,6 +8269,31 @@ The capability has no effect if the nx_huge_pages module parameter is not set. This capability may only be set before any vCPUs are created. +8.39 KVM_CAP_S390_CPU_TOPOLOGY +------------------------------ + +:Capability: KVM_CAP_S390_CPU_TOPOLOGY +:Architectures: s390 +:Type: vm + +This capability indicates that KVM will provide the S390 CPU Topology +facility which consist of the interpretation of the PTF instruction for +the function code 2 along with interception and forwarding of both the +PTF instruction with function codes 0 or 1 and the STSI(15,1,x) +instruction to the userland hypervisor. + +The stfle facility 11, CPU Topology facility, should not be indicated +to the guest without this capability. + +When this capability is present, KVM provides a new attribute group +on vm fd, KVM_S390_VM_CPU_TOPOLOGY. +This new attribute allows to get, set or clear the Modified Change +Topology Report (MTCR) bit of the SCA through the kvm_device_attr +structure. + +When getting the Modified Change Topology Report value, the attr->addr +must point to a byte where the value will be stored or retrieved from. + 9. Known KVM API problems ========================= |