On 12/19/2024 10:40 AM, Nuno Das Neves wrote: > On 12/18/2024 12:54 PM, Roman Kisel wrote: >> Commit bc905fa8b633 ("hyperv: Switch from hyperv-tlfs.h to hyperv/hvhdk.h") >> changed the type of the output pointer to `struct hv_register_assoc` from >> `struct hv_get_vp_registers_output`. That leads to an incorrect computation, >> and leaves the system broken. >> > My bad! But, lets not use `struct hv_get_registers_output`. Instead, use > `struct hv_register_value`, since that is the more complete definition of a > register value. The output of the get_vp_registers hypercall is just an array > of these values. > > Ideally we remove `struct hv_get_vp_registers_output` at some point, since > it serves the same role as `struct hv_register_value` but in a more limited > capacity. > > Thanks > Nuno > I had much the same conversation with Roman off-list yesterday. The choice is between using hv_get_registers_output which is clearly the output of the GetVpRegisters hypercall by name, albeit limited as you said, and hv_register_value which is the more complete definition and what the hypervisor actually returns, but does not currently include the arm64 definitions in our copy of hvgdk_mini.h. hv_get_registers_output and hv_register_value overlap in layout for Roman's purposes. FWIW, I'm in favor of adding the arm64 definitions to hv_register_value and using it for this get_vtl() patch. This could be accompanied with migration of hv_get_vpreg128 in arm64/ and removal of struct hv_get_registers_output, or that could be deferred to a later patch. - Easwar