| Message ID | 1555086498-26691-14-git-send-email-Dave.Martin@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: SVE cleanups | expand |
On Fri, Apr 12, 2019 at 05:28:17PM +0100, Dave Martin wrote: > 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 guararntees which error guarantees > 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> > --- > 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 b115b23..74c51c7 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; > @@ -2258,10 +2260,12 @@ 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 > -- > 2.1.4 > Reviewed-by: Andrew Jones <drjones@redhat.com>
On Mon, Apr 15, 2019 at 05:21:32PM +0200, Andrew Jones wrote: > On Fri, Apr 12, 2019 at 05:28:17PM +0100, Dave Martin wrote: > > 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 guararntees which error > > guarantees > > > 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> > > --- > > 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 b115b23..74c51c7 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; > > @@ -2258,10 +2260,12 @@ 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 > > -- > > 2.1.4 > > > > Reviewed-by: Andrew Jones <drjones@redhat.com> Thanks ---Dave
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index b115b23..74c51c7 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; @@ -2258,10 +2260,12 @@ 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
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 guararntees 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> --- Documentation/virtual/kvm/api.txt | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)