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

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

[Hardik Garg]

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(-)

diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 6b67ac6167891..31256cb22b39e 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -787,11 +787,11 @@ static const struct hv_status_info hv_status_infos[] = {
 	_STATUS_INFO(HV_STATUS_INVALID_HYPERCALL_INPUT,		-EINVAL),
 	_STATUS_INFO(HV_STATUS_INVALID_ALIGNMENT,		-EIO),
 	_STATUS_INFO(HV_STATUS_INVALID_PARAMETER,		-EINVAL),
-	_STATUS_INFO(HV_STATUS_ACCESS_DENIED,			-EIO),
+	_STATUS_INFO(HV_STATUS_ACCESS_DENIED,			-EACCES),
 	_STATUS_INFO(HV_STATUS_INVALID_PARTITION_STATE,		-EIO),
-	_STATUS_INFO(HV_STATUS_OPERATION_DENIED,		-EIO),
-	_STATUS_INFO(HV_STATUS_UNKNOWN_PROPERTY,		-EIO),
-	_STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE,	-EIO),
+	_STATUS_INFO(HV_STATUS_OPERATION_DENIED,		-EACCES),
+	_STATUS_INFO(HV_STATUS_UNKNOWN_PROPERTY,		-EINVAL),
+	_STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE,	-EINVAL),
 	_STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY,		-ENOMEM),
 	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY,	-ENOMEM),
 	_STATUS_INFO(HV_STATUS_INSUFFICIENT_ROOT_MEMORY,	-ENOMEM),
@@ -805,11 +805,9 @@ static const struct hv_status_info hv_status_infos[] = {
 	_STATUS_INFO(HV_STATUS_NOT_ACKNOWLEDGED,		-EIO),
 	_STATUS_INFO(HV_STATUS_INVALID_VP_STATE,		-EIO),
 	_STATUS_INFO(HV_STATUS_NO_RESOURCES,			-EIO),
-	_STATUS_INFO(HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED,	-EIO),
+	_STATUS_INFO(HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED,	-EOPNOTSUPP),
 	_STATUS_INFO(HV_STATUS_INVALID_LP_INDEX,		-EINVAL),
 	_STATUS_INFO(HV_STATUS_INVALID_REGISTER_VALUE,		-EINVAL),
-	_STATUS_INFO(HV_STATUS_INVALID_LP_INDEX,		-EIO),
-	_STATUS_INFO(HV_STATUS_INVALID_REGISTER_VALUE,		-EIO),
 	_STATUS_INFO(HV_STATUS_OPERATION_FAILED,		-EIO),
 	_STATUS_INFO(HV_STATUS_TIME_OUT,			-EIO),
 	_STATUS_INFO(HV_STATUS_CALL_PENDING,			-EIO),
-- 
2.34.1

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

[Easwar Hariharan]

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)