On Thu, Jan 11, 2018 at 06:11:35PM +0800, wei.guo.simon@xxxxxxxxx wrote:
> From: Simon Guo <wei.guo.simon@xxxxxxxxx>
>
> This patch adds host emulation when guest PR KVM executes "trechkpt.",
> which is a privileged instruction and will trap into host.
>
> We firstly copy vcpu ongoing content into vcpu tm checkpoint
> content, then perform kvmppc_restore_tm_pr() to do trechkpt.
> with updated vcpu tm checkpoint vals.
>
> Signed-off-by: Simon Guo <wei.guo.simon@xxxxxxxxx>
[snip]
> +static void kvmppc_emulate_trchkpt(struct kvm_vcpu *vcpu)
> +{
> + unsigned long guest_msr = kvmppc_get_msr(vcpu);
> +
> + preempt_disable();
> + vcpu->arch.save_msr_tm = MSR_TS_S;
> + vcpu->arch.save_msr_tm &= ~(MSR_FP | MSR_VEC | MSR_VSX);
This looks odd, since you are clearing bits when you have just set
save_msr_tm to a constant value that doesn't have these bits set.
This could be taken as a sign that the previous line has a bug and you
meant "|=" or something similar instead of "=". I think you probably
did mean "=", in which case you should remove the line clearing
FP/VEC/VSX.
Paul.
