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Diffstat (limited to 'Documentation/virtual')
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index e8875fef3eb8..a1d344d5ff4c 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1350,6 +1350,41 @@ The following flags are defined: If datamatch flag is set, the event will be signaled only if the written value to the registered address is equal to datamatch in struct kvm_ioeventfd. +4.62 KVM_CREATE_SPAPR_TCE + +Capability: KVM_CAP_SPAPR_TCE +Architectures: powerpc +Type: vm ioctl +Parameters: struct kvm_create_spapr_tce (in) +Returns: file descriptor for manipulating the created TCE table + +This creates a virtual TCE (translation control entry) table, which +is an IOMMU for PAPR-style virtual I/O. It is used to translate +logical addresses used in virtual I/O into guest physical addresses, +and provides a scatter/gather capability for PAPR virtual I/O. + +/* for KVM_CAP_SPAPR_TCE */ +struct kvm_create_spapr_tce { + __u64 liobn; + __u32 window_size; +}; + +The liobn field gives the logical IO bus number for which to create a +TCE table. The window_size field specifies the size of the DMA window +which this TCE table will translate - the table will contain one 64 +bit TCE entry for every 4kiB of the DMA window. + +When the guest issues an H_PUT_TCE hcall on a liobn for which a TCE +table has been created using this ioctl(), the kernel will handle it +in real mode, updating the TCE table. H_PUT_TCE calls for other +liobns will cause a vm exit and must be handled by userspace. + +The return value is a file descriptor which can be passed to mmap(2) +to map the created TCE table into userspace. This lets userspace read +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. + 5. The kvm_run structure Application code obtains a pointer to the kvm_run structure by |