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Wed, 11 Aug 2021 09:03:11 -0700 (PDT) Received: from bobo.ibm.com ([118.210.97.79]) by smtp.gmail.com with ESMTPSA id k19sm6596494pff.28.2021.08.11.09.03.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Aug 2021 09:03:11 -0700 (PDT) From: Nicholas Piggin To: kvm-ppc@vger.kernel.org Subject: [PATCH v2 33/60] KVM: PPC: Book3S HV P9: Avoid SPR scoreboard stalls Date: Thu, 12 Aug 2021 02:01:07 +1000 Message-Id: <20210811160134.904987-34-npiggin@gmail.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20210811160134.904987-1-npiggin@gmail.com> References: <20210811160134.904987-1-npiggin@gmail.com> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, Nicholas Piggin Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Avoid interleaving mfSPR and mtSPR to reduce SPR scoreboard stalls. Signed-off-by: Nicholas Piggin --- arch/powerpc/kvm/book3s_hv.c | 8 ++++---- arch/powerpc/kvm/book3s_hv_p9_entry.c | 19 +++++++++++-------- 2 files changed, 15 insertions(+), 12 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index a390980b42d8..823e501c5ebe 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4307,10 +4307,6 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit, store_spr_state(vcpu); - timer_rearm_host_dec(*tb); - - restore_p9_host_os_sprs(vcpu, &host_os_sprs); - store_fp_state(&vcpu->arch.fp); #ifdef CONFIG_ALTIVEC store_vr_state(&vcpu->arch.vr); @@ -4325,6 +4321,10 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit, switch_pmu_to_host(vcpu, &host_os_sprs); + timer_rearm_host_dec(*tb); + + restore_p9_host_os_sprs(vcpu, &host_os_sprs); + vc->entry_exit_map = 0x101; vc->in_guest = 0; diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c index 2bd96d8256d1..bd0021cd3a67 100644 --- a/arch/powerpc/kvm/book3s_hv_p9_entry.c +++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c @@ -228,6 +228,9 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc host_dawrx1 = mfspr(SPRN_DAWRX1); } + local_paca->kvm_hstate.host_purr = mfspr(SPRN_PURR); + local_paca->kvm_hstate.host_spurr = mfspr(SPRN_SPURR); + if (vc->tb_offset) { u64 new_tb = *tb + vc->tb_offset; mtspr(SPRN_TBU40, new_tb); @@ -244,8 +247,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc mtspr(SPRN_DPDES, vc->dpdes); mtspr(SPRN_VTB, vc->vtb); - local_paca->kvm_hstate.host_purr = mfspr(SPRN_PURR); - local_paca->kvm_hstate.host_spurr = mfspr(SPRN_SPURR); mtspr(SPRN_PURR, vcpu->arch.purr); mtspr(SPRN_SPURR, vcpu->arch.spurr); @@ -448,10 +449,8 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc /* Advance host PURR/SPURR by the amount used by guest */ purr = mfspr(SPRN_PURR); spurr = mfspr(SPRN_SPURR); - mtspr(SPRN_PURR, local_paca->kvm_hstate.host_purr + - purr - vcpu->arch.purr); - mtspr(SPRN_SPURR, local_paca->kvm_hstate.host_spurr + - spurr - vcpu->arch.spurr); + local_paca->kvm_hstate.host_purr += purr - vcpu->arch.purr; + local_paca->kvm_hstate.host_spurr += spurr - vcpu->arch.spurr; vcpu->arch.purr = purr; vcpu->arch.spurr = spurr; @@ -464,6 +463,9 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc vcpu->arch.shregs.sprg2 = mfspr(SPRN_SPRG2); vcpu->arch.shregs.sprg3 = mfspr(SPRN_SPRG3); + vc->dpdes = mfspr(SPRN_DPDES); + vc->vtb = mfspr(SPRN_VTB); + dec = mfspr(SPRN_DEC); if (!(lpcr & LPCR_LD)) /* Sign extend if not using large decrementer */ dec = (s32) dec; @@ -481,6 +483,9 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc vc->tb_offset_applied = 0; } + mtspr(SPRN_PURR, local_paca->kvm_hstate.host_purr); + mtspr(SPRN_SPURR, local_paca->kvm_hstate.host_spurr); + /* Preserve PSSCR[FAKE_SUSPEND] until we've called kvmppc_save_tm_hv */ mtspr(SPRN_PSSCR, host_psscr | (local_paca->kvm_hstate.fake_suspend << PSSCR_FAKE_SUSPEND_LG)); @@ -509,8 +514,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc if (cpu_has_feature(CPU_FTR_ARCH_31)) asm volatile(PPC_CP_ABORT); - vc->dpdes = mfspr(SPRN_DPDES); - vc->vtb = mfspr(SPRN_VTB); mtspr(SPRN_DPDES, 0); if (vc->pcr) mtspr(SPRN_PCR, PCR_MASK);