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 11.1.1. Paged-Response Resolution

 When system software cannot immediately resolve a fault generated by the PSL, a Continue response is written to the PSL_TFC_An Register (PSL_TFC_An[C] = '1'). The corresponding AFU commands also receive a Paged response indicating that the requested operation will not be completed. Offset x'50' and x'58' in the AFU descriptor provide a mechanism for the AFU to be notified when the fault has been resolved by system software and the how the fault was resolved.

 When the AFU supports receiving a paged-resolution response (AFU descriptor offset x'50' bit 0 = '1'), system software must issue a write to the AFU descriptor at offset x'50' followed by a write to offset x'58' for every operation that results in a data storage/segment interrupt (DSI), where the response is a Continue response (PSL_TFC_An[C] = '1'). This MMIO sequence is referred to as the resolution MMIO sequence unless the process has been terminated. AFU descriptor offset x'50' is written with the value read from the PSL_PEHandle_An for the corresponding DSI.

 System software does not guarantee any upper bound on the time between the Continue response and the resolution MMIO sequence. Furthermore, the resolution MMIO sequence is not guaranteed to be in the same order as the Continue responses.

 System software must guarantee that after a process has been terminated, all the resolution MMIO sequences will be performed or discarded before the process element is removed. After the process element remove command has been issued, there shall not be any resolution MMIO sequences issued for that process.

 An AFU that blocks waiting for the MMIO sequence to restart an operation should also implement a time-out for the case where the requested data is paged out of system memory. How the command is restarted is implementation specific.


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