From 3e7b3379023dad2e78c3200373a6368f5d0ee599 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin <npiggin@gmail.com> Date: Tue, 23 Nov 2021 19:52:11 +1000 Subject: [PATCH] KVM: PPC: Book3S HV P9: Switch PMU to guest as late as possible This moves PMU switch to guest as late as possible in entry, and switch back to host as early as possible at exit. This helps the host get the most perf coverage of KVM entry/exit code as possible. This is slightly suboptimal for SPR scheduling point of view when the PMU is enabled, but when perf is disabled there is no real difference. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-34-npiggin@gmail.com --- arch/powerpc/kvm/book3s_hv.c | 6 ++---- arch/powerpc/kvm/book3s_hv_p9_entry.c | 6 ++---- 2 files changed, 4 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 40bee0d61482..c14467cf23d3 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -3833,8 +3833,6 @@ static int kvmhv_vcpu_entry_p9_nested(struct kvm_vcpu *vcpu, u64 time_limit, uns s64 dec; int trap; - switch_pmu_to_guest(vcpu, &host_os_sprs); - save_p9_host_os_sprs(&host_os_sprs); /* @@ -3897,9 +3895,11 @@ static int kvmhv_vcpu_entry_p9_nested(struct kvm_vcpu *vcpu, u64 time_limit, uns mtspr(SPRN_DAR, vcpu->arch.shregs.dar); mtspr(SPRN_DSISR, vcpu->arch.shregs.dsisr); + switch_pmu_to_guest(vcpu, &host_os_sprs); trap = plpar_hcall_norets(H_ENTER_NESTED, __pa(&hvregs), __pa(&vcpu->arch.regs)); kvmhv_restore_hv_return_state(vcpu, &hvregs); + switch_pmu_to_host(vcpu, &host_os_sprs); vcpu->arch.shregs.msr = vcpu->arch.regs.msr; vcpu->arch.shregs.dar = mfspr(SPRN_DAR); vcpu->arch.shregs.dsisr = mfspr(SPRN_DSISR); @@ -3918,8 +3918,6 @@ static int kvmhv_vcpu_entry_p9_nested(struct kvm_vcpu *vcpu, u64 time_limit, uns restore_p9_host_os_sprs(vcpu, &host_os_sprs); - switch_pmu_to_host(vcpu, &host_os_sprs); - return trap; } diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c index 6bef509bccb8..619bbcd47b92 100644 --- a/arch/powerpc/kvm/book3s_hv_p9_entry.c +++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c @@ -601,8 +601,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc local_paca->kvm_hstate.host_purr = mfspr(SPRN_PURR); local_paca->kvm_hstate.host_spurr = mfspr(SPRN_SPURR); - switch_pmu_to_guest(vcpu, &host_os_sprs); - save_p9_host_os_sprs(&host_os_sprs); /* @@ -744,7 +742,9 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc accumulate_time(vcpu, &vcpu->arch.guest_time); + switch_pmu_to_guest(vcpu, &host_os_sprs); kvmppc_p9_enter_guest(vcpu); + switch_pmu_to_host(vcpu, &host_os_sprs); accumulate_time(vcpu, &vcpu->arch.rm_intr); @@ -955,8 +955,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc asm volatile(PPC_CP_ABORT); out: - switch_pmu_to_host(vcpu, &host_os_sprs); - end_timing(vcpu); return trap; -- 2.30.9