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. 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 eret to enter the guest (__guest_enter) and eret in kvm_call_hyp for __kvm_vcpu_run_nvhe on returning. Signed-off-by: Andrew Murray <[email protected]> --- arch/arm64/include/asm/kvm_host.h | 3 +++ arch/arm64/kvm/hyp/switch.c | 6 +++++ arch/arm64/kvm/pmu.c | 40 +++++++++++++++++++++++++++++++ 3 files changed, 49 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 4b7219128f2d..7ca4e094626d 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -498,6 +498,9 @@ static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu) void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr); void kvm_clr_pmu_events(u32 clr); + +void __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt); +bool __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt); #else static inline void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr) {} static inline void kvm_clr_pmu_events(u32 clr) {} diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 421ebf6f7086..7c543ff7e458 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -523,6 +523,7 @@ 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); @@ -531,6 +532,8 @@ 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)); @@ -577,6 +580,9 @@ 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; } diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c index 43965a3cc0f4..a1cee7919953 100644 --- a/arch/arm64/kvm/pmu.c +++ b/arch/arm64/kvm/pmu.c @@ -7,6 +7,7 @@ */ #include <linux/kvm_host.h> #include <linux/perf_event.h> +#include <asm/kvm_hyp.h> DECLARE_PER_CPU(kvm_host_data_t, kvm_host_data); @@ -47,3 +48,42 @@ void kvm_clr_pmu_events(u32 clr) ctx->pmu_events.events_host &= ~clr; ctx->pmu_events.events_guest &= ~clr; } + +/** + * Disable host events, enable guest events + */ +bool __hyp_text __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt) +{ + struct kvm_host_data *host; + struct kvm_pmu_events *pmu; + + host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); + pmu = &host->pmu_events; + + if (pmu->events_host) + write_sysreg(pmu->events_host, pmcntenclr_el0); + + if (pmu->events_guest) + write_sysreg(pmu->events_guest, pmcntenset_el0); + + return (pmu->events_host || pmu->events_guest); +} + +/** + * Disable guest events, enable host events + */ +void __hyp_text __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt) +{ + struct kvm_host_data *host; + struct kvm_pmu_events *pmu; + + host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); + pmu = &host->pmu_events; + + if (pmu->events_guest) + write_sysreg(pmu->events_guest, pmcntenclr_el0); + + if (pmu->events_host) + write_sysreg(pmu->events_host, pmcntenset_el0); +} + -- 2.21.0 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
