Re: [PATCH 03/13] KVM: PPC: Book3S HV: Ensure MSR[ME] is always set in guest MSR

[Fabiano Rosas <farosas@linux.ibm.com>]

Nicholas Piggin <npiggin@gmail.com> writes:

> Rather than add the ME bit to the MSR when the guest is entered, make
> it clear that the hypervisor does not allow the guest to clear the bit.
>
> The ME addition is kept in the code for now, but a future patch will
> warn if it's not present.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>

> ---
>  arch/powerpc/kvm/book3s_hv_builtin.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
> index dad118760a4e..ae8f291c5c48 100644
> --- a/arch/powerpc/kvm/book3s_hv_builtin.c
> +++ b/arch/powerpc/kvm/book3s_hv_builtin.c
> @@ -661,6 +661,13 @@ static void kvmppc_end_cede(struct kvm_vcpu *vcpu)
>
>  void kvmppc_set_msr_hv(struct kvm_vcpu *vcpu, u64 msr)
>  {
> +	/*
> +	 * Guest must always run with machine check interrupt
> +	 * enabled.
> +	 */
> +	if (!(msr & MSR_ME))
> +		msr |= MSR_ME;
> +
>  	/*
>  	 * Check for illegal transactional state bit combination
>  	 * and if we find it, force the TS field to a safe state.