From fe365b4ea6c0df3eb44d636c32c5210ae1e58364 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Fri, 12 Apr 2019 12:59:47 +0100 Subject: [PATCH] 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 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 Reviewed-by: Andrew Jones Signed-off-by: Marc Zyngier --- 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 -- 2.30.2