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Diffstat (limited to 'doc/opal-api/opal-npu2-141-142-143.rst')
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diff --git a/doc/opal-api/opal-npu2-141-142-143.rst b/doc/opal-api/opal-npu2-141-142-143.rst new file mode 100644 index 0000000..541051c --- /dev/null +++ b/doc/opal-api/opal-npu2-141-142-143.rst @@ -0,0 +1,66 @@ +OPAL NPU2 calls +================ + +There are three OPAL calls for interacting with NPU2 devices: :: + +#define OPAL_NPU_INIT_CONTEXT 141 +#define OPAL_NPU_DESTROY_CONTEXT 142 +#define OPAL_NPU_MAP_LPAR 143 + +These are used to setup and configure address translation services +(ATS) for a given NVLink2 device. Note that in some documentation this +is also referred to as extended translation services (XTS). + +Each NVLink2 supports multiple processes running on a GPU which issues +requests for address translation. The NPU2 is responsible for +completing the request by forwarding it to the Nest MMU (NMMU) along +with the appropriate translation context (MSR/LPCR) bits. These bits +are keyed off a 20-bit process ID (PASID/PID) which is identical to +the PID used on the processor. + +The OPAL calls documented here are used to setup/destroy the +appropriate context for a given process on a given NVLink2 device. + +OPAL_NPU_INIT_CONTEXT +--------------------- + +Parameters: :: + + uint64_t phb_id + int pasid + uint64_t msr + uint64_t lpid + +Allocates a new context ID and sets up the given PASID/PID to be +associated with the supplied MSR on for the given LPID. MSR should +only contain bits set requried for NPU2 address lookups - ie. MSR +DR/HV/PR/SF. + +Returns the context ID on success or ``OPAL_RESOURCE`` if no more +contexts are available or ``OPAL_UNSUPPORTED`` in the case of +unsupported MSR bits. + +OPAL_NPU_DESTROY_CONTEXT +------------------------ + +Parameters: :: + + uint64_t phb_id + uint64_t id + +Destroys a previously allocated context ID. This may cause further +translation requests from the GPU to fail. + +OPAL_NPU_MAP_LPAR +----------------- + +Parameters: :: + + uint64_t phb_id + uint64_t bdf + uint64_t lparid + uint64_t lpcr + +Associates the given GPU BDF with a particular LPAR and LPCR +bits. Hash mode ATS is currently unsupported so lpcr should be set +to 0. |