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authorDave Martin <Dave.Martin@arm.com>2019-04-12 12:59:47 +0100
committerMarc Zyngier <marc.zyngier@arm.com>2019-04-18 17:14:02 +0100
commitfe365b4ea6c0df3eb44d636c32c5210ae1e58364 (patch)
tree68edebaa7fef3066294a6d730d3268c235216781 /Documentation/virtual
parent9df2d660c7f37aed7244ec0b920c0749dbb69167 (diff)
downloadlinux-fe365b4ea6c0df3eb44d636c32c5210ae1e58364.tar.bz2
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.txt14
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