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authorCarsten Otte <cotte@de.ibm.com>2012-01-04 13:25:21 +0400
committerAvi Kivity <avi@redhat.com>2012-03-05 16:52:18 +0400
commit27e0393f15fc8bc855c6a888387ff5ffd2181089 (patch)
tree7dd5f6f49f6e11ee5cfbbc4d00fb39f649caa61b /Documentation/virtual
parente08b96371625aaa84cb03f51acc4c8e0be27403a (diff)
downloadlinux-27e0393f15fc8bc855c6a888387ff5ffd2181089.tar.xz
KVM: s390: ucontrol: per vcpu address spaces
This patch introduces two ioctls for virtual cpus, that are only valid for kernel virtual machines that are controlled by userspace. Each virtual cpu has its individual address space in this mode of operation, and each address space is backed by the gmap implementation just like the address space for regular KVM guests. KVM_S390_UCAS_MAP allows to map a part of the user's virtual address space to the vcpu. Starting offset and length in both the user and the vcpu address space need to be aligned to 1M. KVM_S390_UCAS_UNMAP can be used to unmap a range of memory from a virtual cpu in a similar way. Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/api.txt38
1 files changed, 38 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 579d40b26a5a..ee394b263261 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1496,6 +1496,44 @@ following algorithm:
Some guests configure the LINT1 NMI input to cause a panic, aiding in
debugging.
+4.64 KVM_S390_UCAS_MAP
+
+Capability: KVM_CAP_S390_UCONTROL
+Architectures: s390
+Type: vcpu ioctl
+Parameters: struct kvm_s390_ucas_mapping (in)
+Returns: 0 in case of success
+
+The parameter is defined like this:
+ struct kvm_s390_ucas_mapping {
+ __u64 user_addr;
+ __u64 vcpu_addr;
+ __u64 length;
+ };
+
+This ioctl maps the memory at "user_addr" with the length "length" to
+the vcpu's address space starting at "vcpu_addr". All parameters need to
+be alligned by 1 megabyte.
+
+4.65 KVM_S390_UCAS_UNMAP
+
+Capability: KVM_CAP_S390_UCONTROL
+Architectures: s390
+Type: vcpu ioctl
+Parameters: struct kvm_s390_ucas_mapping (in)
+Returns: 0 in case of success
+
+The parameter is defined like this:
+ struct kvm_s390_ucas_mapping {
+ __u64 user_addr;
+ __u64 vcpu_addr;
+ __u64 length;
+ };
+
+This ioctl unmaps the memory in the vcpu's address space starting at
+"vcpu_addr" with the length "length". The field "user_addr" is ignored.
+All parameters need to be alligned by 1 megabyte.
+
5. The kvm_run structure
Application code obtains a pointer to the kvm_run structure by