Re: [PATCH] Drivers: hv: Use meaningful errnos for hypercall status codes

[Easwar Hariharan <easwar.hariharan@linux.microsoft.com>]

Hi Hardik,

On 7/27/2026 14:11, Hardik Garg wrote:
> Commit 3817854ba892 ("hyperv: Log hypercall status codes as strings")
> converted hv_result_to_errno() from a switch to a table and added status
> codes used for string logging. Statuses without an existing specific
> mapping were assigned the generic -EIO fallback even when a more specific
> errno was available.
> 
> Map HV_STATUS_ACCESS_DENIED and HV_STATUS_OPERATION_DENIED to -EACCES,
> HV_STATUS_UNKNOWN_PROPERTY and HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE to
> -EINVAL, and HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED to -EOPNOTSUPP.
> This lets callers distinguish permission, argument, and capability
> failures from generic I/O errors.
> 
> The table conversion also added duplicate HV_STATUS_INVALID_LP_INDEX and
> HV_STATUS_INVALID_REGISTER_VALUE entries. Remove the later -EIO entries,
> which are unreachable because find_hv_status_info() returns the first
> match.
> 
> Signed-off-by: Hardik Garg <hargar@linux.microsoft.com>
> ---
>  drivers/hv/hv_common.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
Glad to see that this was something that bothered you as well. If you like, you
can pick up feedback from Nuno on my attempt to solve this [1] and do a de-facto v3.

[1] https://lore.kernel.org/all/479242d4-ae08-442c-b61b-c9408ba2e9b0@linux.microsoft.com/

Thanks,
Easwar (he/him)