From: Nicholas Piggin Date: Tue, 23 Nov 2021 09:52:11 +0000 (+1000) Subject: KVM: PPC: Book3S HV P9: Switch PMU to guest as late as possible X-Git-Tag: v6.1-rc5~2050^2~150^2~24 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3e7b3379023dad2e78c3200373a6368f5d0ee599;p=platform%2Fkernel%2Flinux-starfive.git 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 Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211123095231.1036501-34-npiggin@gmail.com --- diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 40bee0d..c14467c 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 6bef509..619bbcd 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 @@ tm_return_to_guest: 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 @@ tm_return_to_guest: asm volatile(PPC_CP_ABORT); out: - switch_pmu_to_host(vcpu, &host_os_sprs); - end_timing(vcpu); return trap;