On Mon, Feb 18, 2019 at 11:00:19PM +0100, Christoffer Dall wrote: > On Mon, Jan 14, 2019 at 04:11:48PM +0000, Andrew Murray wrote: > > Enable/disable event counters as appropriate when entering and exiting > > the guest to enable support for guest or host only event counting. > > > > For both VHE and non-VHE we switch the counters between host/guest at > > EL2. EL2 is filtered out by the PMU when we are using the :G modifier. > > I don't think the last part is strictly true as per the former patch on > a non-vhe system if you have the :h modifier, so maybe just leave that > out of the commit message.
OK I'll remove that. > > > > > The PMU may be on when we change which counters are enabled however > > we avoid adding an isb as we instead rely on existing context > > synchronisation events: the isb in kvm_arm_vhe_guest_exit for VHE and > > the eret from the hvc in kvm_call_hyp. > > > > Signed-off-by: Andrew Murray <[email protected]> > > Reviewed-by: Suzuki K Poulose <[email protected]> > > --- > > arch/arm64/kvm/hyp/switch.c | 60 > > +++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 60 insertions(+) > > > > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c > > index b0b1478..9018fb3 100644 > > --- a/arch/arm64/kvm/hyp/switch.c > > +++ b/arch/arm64/kvm/hyp/switch.c > > @@ -357,6 +357,54 @@ static bool __hyp_text __hyp_switch_fpsimd(struct > > kvm_vcpu *vcpu) > > return true; > > } > > > > +static bool __hyp_text __pmu_switch_to_guest(struct kvm_cpu_context > > *host_ctxt) > > +{ > > + struct kvm_host_data *host; > > + struct kvm_pmu_events *pmu; > > + u32 clr, set; > > + > > + host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); > > + pmu = &host->pmu_events; > > + > > + /* We can potentially avoid a sysreg write by only changing bits that > > + * differ between the guest/host. E.g. where events are enabled in > > + * both guest and host > > + */ > > super nit: kernel coding style requires 'wings' on both side of a > multi-line comment. Only if you respin anyhow. Ah I didn't notice that, I'll fix this up. Thanks for the review. Andrew Murray > > > + clr = pmu->events_host & ~pmu->events_guest; > > + set = pmu->events_guest & ~pmu->events_host; > > + > > + if (clr) > > + write_sysreg(clr, pmcntenclr_el0); > > + > > + if (set) > > + write_sysreg(set, pmcntenset_el0); > > + > > + return (clr || set); > > +} > > + > > +static void __hyp_text __pmu_switch_to_host(struct kvm_cpu_context > > *host_ctxt) > > +{ > > + struct kvm_host_data *host; > > + struct kvm_pmu_events *pmu; > > + u32 clr, set; > > + > > + host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); > > + pmu = &host->pmu_events; > > + > > + /* We can potentially avoid a sysreg write by only changing bits that > > + * differ between the guest/host. E.g. where events are enabled in > > + * both guest and host > > + */ > > ditto > > > + clr = pmu->events_guest & ~pmu->events_host; > > + set = pmu->events_host & ~pmu->events_guest; > > + > > + if (clr) > > + write_sysreg(clr, pmcntenclr_el0); > > + > > + if (set) > > + write_sysreg(set, pmcntenset_el0); > > +} > > + > > /* > > * Return true when we were able to fixup the guest exit and should return > > to > > * the guest, false when we should restore the host state and return to the > > @@ -464,12 +512,15 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) > > { > > struct kvm_cpu_context *host_ctxt; > > struct kvm_cpu_context *guest_ctxt; > > + bool pmu_switch_needed; > > u64 exit_code; > > > > host_ctxt = vcpu->arch.host_cpu_context; > > host_ctxt->__hyp_running_vcpu = vcpu; > > guest_ctxt = &vcpu->arch.ctxt; > > > > + pmu_switch_needed = __pmu_switch_to_guest(host_ctxt); > > + > > sysreg_save_host_state_vhe(host_ctxt); > > > > /* > > @@ -511,6 +562,9 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) > > > > __debug_switch_to_host(vcpu); > > > > + if (pmu_switch_needed) > > + __pmu_switch_to_host(host_ctxt); > > + > > return exit_code; > > } > > > > @@ -519,6 +573,7 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu > > *vcpu) > > { > > struct kvm_cpu_context *host_ctxt; > > struct kvm_cpu_context *guest_ctxt; > > + bool pmu_switch_needed; > > u64 exit_code; > > > > vcpu = kern_hyp_va(vcpu); > > @@ -527,6 +582,8 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu > > *vcpu) > > host_ctxt->__hyp_running_vcpu = vcpu; > > guest_ctxt = &vcpu->arch.ctxt; > > > > + pmu_switch_needed = __pmu_switch_to_guest(host_ctxt); > > + > > __sysreg_save_state_nvhe(host_ctxt); > > > > __activate_vm(kern_hyp_va(vcpu->kvm)); > > @@ -573,6 +630,9 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu > > *vcpu) > > */ > > __debug_switch_to_host(vcpu); > > > > + if (pmu_switch_needed) > > + __pmu_switch_to_host(host_ctxt); > > + > > return exit_code; > > } > > > > -- > > 2.7.4 > > > > Thanks, > > Christoffer _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
