Hi Paul,
On Tue, Jan 23, 2018 at 08:36:44PM +1100, Paul Mackerras wrote:
> 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.
I will rework and remove "save_msr_tm" from the code.
Thanks,
- Simon
