KVM: arm64: Fix the KVM_ARM_PREFERRED_TARGET documentation

KVM_ARM_PREFERRED_TARGET has never set a feature bit: the original arm64 implementation zeroed the bitmap, and kvm_vcpu_preferred_target(), which only ever zeroed it, was removed by commit 5346f7e13e5e ("KVM: arm64:
Always return generic v8 as the preferred target"). The ENODEV error had gone earlier still, with commit 08e873cb70f3 ("KVM: arm64: Change the return type of kvm_vcpu_preferred_target()"). Document what it returns, that userspace selects vCPU features itself, and drop the error.

No functional change intended.

Signed-off-by Fuad Tabba <[email protected]>

---
 Documentation/virt/kvm/api.rst | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

Documentation/virt/kvm/api.rst +5 -11

index e0430cc750c9e..193f3b0ec77d1 100644
@@ -3600,20 +3600,14 @@ Possible features:
 :Parameters: struct kvm_vcpu_init (out)
 :Returns: 0 on success; -1 on error
 
-Errors:
-
-  ======     ==========================================
-  ENODEV     no preferred target available for the host
-  ======     ==========================================
-
 This queries KVM for preferred CPU target type which can be emulated
 by KVM on underlying host.
 
-The ioctl returns struct kvm_vcpu_init instance containing information
-about preferred CPU target type and recommended features for it.  The
-kvm_vcpu_init->features bitmap returned will have feature bits set if
-the preferred target recommends setting these features, but this is
-not mandatory.
+The ioctl returns a struct kvm_vcpu_init instance containing the
+preferred CPU target type. The kvm_vcpu_init->features bitmap is
+returned empty: userspace selects the vCPU features itself, and their
+availability is reported by the capabilities listed under
+KVM_ARM_VCPU_INIT.
 
 The information returned by this ioctl can be used to prepare an instance
 of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in

base-commit: cee9395acd8043be0644b25c34bfa86623f2b935

Signature · 1 line

2.39.5

KVM_ARM_PREFERRED_TARGET has never set a feature bit: the original arm64 implementation zeroed the bitmap, and kvm_vcpu_preferred_target(), which only ever zeroed it, was removed by commit 5346f7e13e5e ("KVM: arm64:
Always return generic v8 as the preferred target"). The ENODEV error had gone earlier still, with commit 08e873cb70f3 ("KVM: arm64: Change the return type of kvm_vcpu_preferred_target()"). Document what it returns, that userspace selects vCPU features itself, and drop the error.

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