Re: [PATCH] KVM: PPC: Don't return -ENOTSUPP to userspace in ioctls

[Paul Mackerras <paulus@ozlabs.org>]

On Fri, Sep 11, 2020 at 12:53:45PM +0200, Greg Kurz wrote:
> ENOTSUPP is a linux only thingy, the value of which is unknown to
> userspace, not to be confused with ENOTSUP which linux maps to
> EOPNOTSUPP, as permitted by POSIX [1]:
> 
> [EOPNOTSUPP]
> Operation not supported on socket. The type of socket (address family
> or protocol) does not support the requested operation. A conforming
> implementation may assign the same values for [EOPNOTSUPP] and [ENOTSUP].
> 
> Return -EOPNOTSUPP instead of -ENOTSUPP for the following ioctls:
> - KVM_GET_FPU for Book3s and BookE
> - KVM_SET_FPU for Book3s and BookE
> - KVM_GET_DIRTY_LOG for BookE
> 
> This doesn't affect QEMU which doesn't call the KVM_GET_FPU and
> KVM_SET_FPU ioctls on POWER anyway since they are not supported,
> and _buggily_ ignores anything but -EPERM for KVM_GET_DIRTY_LOG.
> 
> [1] https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html
> 
> Signed-off-by: Greg Kurz <groug@kaod.org>

Thanks, applied.

Paul.