[PATCH v4 14/53] KVM: PPC: Book3S HV P9: Factor PMU save/load into context switch functions
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2021-11-23 10:02:06
Subsystem:
kernel virtual machine for powerpc (kvm/powerpc), linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Rather than guest/host save/retsore functions, implement context switch functions that take care of details like the VPA update for nested. The reason to split these kind of helpers into explicit save/load functions is mainly to schedule SPR access nicely, but PMU is a special case where the load requires mtSPR (to stop counters) and other difficulties, so there's less possibility to schedule those nicely. The SPR accesses also have side-effects if the PMU is running, and in later changes we keep the host PMU running as long as possible so this code can be better profiled, which also complicates scheduling. Reviewed-by: Athira Jajeev <redacted> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/kvm/book3s_hv.c | 61 +++++++++++++++++------------------- 1 file changed, 28 insertions(+), 33 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 8fdd640873a3..5ffaaf8a30b3 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c@@ -3830,7 +3830,8 @@ static void freeze_pmu(unsigned long mmcr0, unsigned long mmcra) isync(); } -static void save_p9_host_pmu(struct p9_host_os_sprs *host_os_sprs) +static void switch_pmu_to_guest(struct kvm_vcpu *vcpu, + struct p9_host_os_sprs *host_os_sprs) { if (ppc_get_pmu_inuse()) { /*
@@ -3864,10 +3865,21 @@ static void save_p9_host_pmu(struct p9_host_os_sprs *host_os_sprs) host_os_sprs->sier3 = mfspr(SPRN_SIER3); } } -} -static void load_p9_guest_pmu(struct kvm_vcpu *vcpu) -{ +#ifdef CONFIG_PPC_PSERIES + if (kvmhv_on_pseries()) { + barrier(); + if (vcpu->arch.vpa.pinned_addr) { + struct lppaca *lp = vcpu->arch.vpa.pinned_addr; + get_lppaca()->pmcregs_in_use = lp->pmcregs_in_use; + } else { + get_lppaca()->pmcregs_in_use = 1; + } + barrier(); + } +#endif + + /* load guest */ mtspr(SPRN_PMC1, vcpu->arch.pmc[0]); mtspr(SPRN_PMC2, vcpu->arch.pmc[1]); mtspr(SPRN_PMC3, vcpu->arch.pmc[2]);
@@ -3892,7 +3904,8 @@ static void load_p9_guest_pmu(struct kvm_vcpu *vcpu) /* No isync necessary because we're starting counters */ } -static void save_p9_guest_pmu(struct kvm_vcpu *vcpu) +static void switch_pmu_to_host(struct kvm_vcpu *vcpu, + struct p9_host_os_sprs *host_os_sprs) { struct lppaca *lp; int save_pmu = 1;
@@ -3935,10 +3948,15 @@ static void save_p9_guest_pmu(struct kvm_vcpu *vcpu) } else { freeze_pmu(mfspr(SPRN_MMCR0), mfspr(SPRN_MMCRA)); } -} -static void load_p9_host_pmu(struct p9_host_os_sprs *host_os_sprs) -{ +#ifdef CONFIG_PPC_PSERIES + if (kvmhv_on_pseries()) { + barrier(); + get_lppaca()->pmcregs_in_use = ppc_get_pmu_inuse(); + barrier(); + } +#endif + if (ppc_get_pmu_inuse()) { mtspr(SPRN_PMC1, host_os_sprs->pmc1); mtspr(SPRN_PMC2, host_os_sprs->pmc2);
@@ -4071,8 +4089,6 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit, save_p9_host_os_sprs(&host_os_sprs); - save_p9_host_pmu(&host_os_sprs); - kvmppc_subcore_enter_guest(); vc->entry_exit_map = 1;
@@ -4089,19 +4105,7 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit, cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST)) kvmppc_restore_tm_hv(vcpu, vcpu->arch.shregs.msr, true); -#ifdef CONFIG_PPC_PSERIES - if (kvmhv_on_pseries()) { - barrier(); - if (vcpu->arch.vpa.pinned_addr) { - struct lppaca *lp = vcpu->arch.vpa.pinned_addr; - get_lppaca()->pmcregs_in_use = lp->pmcregs_in_use; - } else { - get_lppaca()->pmcregs_in_use = 1; - } - barrier(); - } -#endif - load_p9_guest_pmu(vcpu); + switch_pmu_to_guest(vcpu, &host_os_sprs); msr_check_and_set(MSR_FP | MSR_VEC | MSR_VSX); load_fp_state(&vcpu->arch.fp);
@@ -4230,14 +4234,7 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit, vcpu->arch.vpa.dirty = 1; } - save_p9_guest_pmu(vcpu); -#ifdef CONFIG_PPC_PSERIES - if (kvmhv_on_pseries()) { - barrier(); - get_lppaca()->pmcregs_in_use = ppc_get_pmu_inuse(); - barrier(); - } -#endif + switch_pmu_to_host(vcpu, &host_os_sprs); vc->entry_exit_map = 0x101; vc->in_guest = 0;
@@ -4246,8 +4243,6 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit, mtspr(SPRN_SPRG_VDSO_WRITE, local_paca->sprg_vdso); - load_p9_host_pmu(&host_os_sprs); - kvmppc_subcore_exit_guest(); return trap;
--
2.23.0