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. > > 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. > + 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
