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authorClaudio Imbrenda <imbrenda@linux.vnet.ibm.com>2016-08-04 17:54:42 +0200
committerChristian Borntraeger <borntraeger@de.ibm.com>2017-06-22 12:41:05 +0200
commit190df4a212a708fdd18f6cabfdd82594c91fdf25 (patch)
tree14e26591a41b51f4c0f779980d801b63d52c4443 /Documentation/virtual
parent865279c53ca9d88718d974bb014b2c6ce259ac75 (diff)
KVM: s390: CMMA tracking, ESSA emulation, migration mode
* Add a migration state bitmap to keep track of which pages have dirty CMMA information. * Disable CMMA by default, so we can track if it's used or not. Enable it on first use like we do for storage keys (unless we are doing a migration). * Creates a VM attribute to enter and leave migration mode. * In migration mode, CMMA is disabled in the SIE block, so ESSA is always interpreted and emulated in software. * Free the migration state on VM destroy. Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/devices/vm.txt33
1 files changed, 33 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt
index 575ccb022aac..903fc926860b 100644
--- a/Documentation/virtual/kvm/devices/vm.txt
+++ b/Documentation/virtual/kvm/devices/vm.txt
@@ -222,3 +222,36 @@ Allows user space to disable dea key wrapping, clearing the wrapping key.
Parameters: none
Returns: 0
+
+5. GROUP: KVM_S390_VM_MIGRATION
+Architectures: s390
+
+5.1. ATTRIBUTE: KVM_S390_VM_MIGRATION_STOP (w/o)
+
+Allows userspace to stop migration mode, needed for PGSTE migration.
+Setting this attribute when migration mode is not active will have no
+effects.
+
+Parameters: none
+Returns: 0
+
+5.2. ATTRIBUTE: KVM_S390_VM_MIGRATION_START (w/o)
+
+Allows userspace to start migration mode, needed for PGSTE migration.
+Setting this attribute when migration mode is already active will have
+no effects.
+
+Parameters: none
+Returns: -ENOMEM if there is not enough free memory to start migration mode
+ -EINVAL if the state of the VM is invalid (e.g. no memory defined)
+ 0 in case of success.
+
+5.3. ATTRIBUTE: KVM_S390_VM_MIGRATION_STATUS (r/o)
+
+Allows userspace to query the status of migration mode.
+
+Parameters: address of a buffer in user space to store the data (u64) to;
+ the data itself is either 0 if migration mode is disabled or 1
+ if it is enabled
+Returns: -EFAULT if the given address is not accessible from kernel space
+ 0 in case of success.