From: Dave Martin <Dave.Martin@xxxxxxx>
The current error code documentation for KVM_GET_ONE_REG and
KVM_SET_ONE_REG could be read as implying that all architectures
implement these error codes, or that KVM guarantees which error
code is returned in a particular situation.
Because this is not really the case, this patch waters down the
documentation explicitly to remove such guarantees.
EPERM is marked as arm64-specific, since for now arm64 really is
the only architecture that yields this error code for the
finalization-required case. Keeping this as a distinct error code
is useful however for debugging due to the statefulness of the API
in this instance.
No functional change.
Suggested-by: Andrew Jones <drjones@xxxxxxxxxx>
Fixes: 395f562f2b4c ("KVM: Document errors for KVM_GET_ONE_REG and KVM_SET_ONE_REG")
Fixes: 50036ad06b7f ("KVM: arm64/sve: Document KVM API extensions for SVE")
Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
Documentation/virtual/kvm/api.txt | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 5519df0d3ed0..818ac97fdabc 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1873,8 +1873,10 @@ Parameters: struct kvm_one_reg (in)
Returns: 0 on success, negative value on failure
Errors:
ENOENT: no such register
- EPERM: register access forbidden for architecture-dependent reasons
- EINVAL: other errors, such as bad size encoding for a known register
+ EINVAL: invalid register ID, or no such register
+ EPERM: (arm64) register access not allowed before vcpu finalization
+(These error codes are indicative only: do not rely on a specific error
+code being returned in a specific situation.)
struct kvm_one_reg {
__u64 id;
@@ -2260,10 +2262,12 @@ Architectures: all
Type: vcpu ioctl
Parameters: struct kvm_one_reg (in and out)
Returns: 0 on success, negative value on failure
-Errors:
+Errors include:
ENOENT: no such register
- EPERM: register access forbidden for architecture-dependent reasons
- EINVAL: other errors, such as bad size encoding for a known register
+ EINVAL: invalid register ID, or no such register
+ EPERM: (arm64) register access not allowed before vcpu finalization
+(These error codes are indicative only: do not rely on a specific error
+code being returned in a specific situation.)
This ioctl allows to receive the value of a single register implemented
in a vcpu. The register to read is indicated by the "id" field of the
--
2.20.1
