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Diffstat (limited to 'Documentation/virtual')
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 681871311d3e..b0e4b9cd6a66 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1398,6 +1398,38 @@ the entries written by kernel-handled H_PUT_TCE calls, and also lets userspace update the TCE table directly which is useful in some circumstances. +4.63 KVM_ALLOCATE_RMA + +Capability: KVM_CAP_PPC_RMA +Architectures: powerpc +Type: vm ioctl +Parameters: struct kvm_allocate_rma (out) +Returns: file descriptor for mapping the allocated RMA + +This allocates a Real Mode Area (RMA) from the pool allocated at boot +time by the kernel. An RMA is a physically-contiguous, aligned region +of memory used on older POWER processors to provide the memory which +will be accessed by real-mode (MMU off) accesses in a KVM guest. +POWER processors support a set of sizes for the RMA that usually +includes 64MB, 128MB, 256MB and some larger powers of two. + +/* for KVM_ALLOCATE_RMA */ +struct kvm_allocate_rma { + __u64 rma_size; +}; + +The return value is a file descriptor which can be passed to mmap(2) +to map the allocated RMA into userspace. The mapped area can then be +passed to the KVM_SET_USER_MEMORY_REGION ioctl to establish it as the +RMA for a virtual machine. The size of the RMA in bytes (which is +fixed at host kernel boot time) is returned in the rma_size field of +the argument structure. + +The KVM_CAP_PPC_RMA capability is 1 or 2 if the KVM_ALLOCATE_RMA ioctl +is supported; 2 if the processor requires all virtual machines to have +an RMA, or 1 if the processor can use an RMA but doesn't require it, +because it supports the Virtual RMA (VRMA) facility. + 5. The kvm_run structure Application code obtains a pointer to the kvm_run structure by |