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| author | Dave Martin <Dave.Martin@arm.com> | 2019-04-12 12:59:47 +0100 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2019-04-18 17:14:02 +0100 |
| commit | fe365b4ea6c0df3eb44d636c32c5210ae1e58364 (patch) | |
| tree | 68edebaa7fef3066294a6d730d3268c235216781 /Documentation/virtual | |
| parent | 9df2d660c7f37aed7244ec0b920c0749dbb69167 (diff) | |
| download | lwn-fe365b4ea6c0df3eb44d636c32c5210ae1e58364.tar.gz lwn-fe365b4ea6c0df3eb44d636c32c5210ae1e58364.zip | |
KVM: Clarify KVM_{SET,GET}_ONE_REG error code documentation
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@redhat.com>
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@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'Documentation/virtual')
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 14 |
1 files 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 |