From: Nicholas Piggin <npiggin@gmail.com>
To: kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH v3 25/52] KVM: PPC: Book3S HV P9: Avoid SPR scoreboard stalls
Date: Tue, 5 Oct 2021 02:00:22 +1000 [thread overview]
Message-ID: <20211004160049.1338837-26-npiggin@gmail.com> (raw)
In-Reply-To: <20211004160049.1338837-1-npiggin@gmail.com>
Avoid interleaving mfSPR and mtSPR to reduce SPR scoreboard stalls.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
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 f3c052b8b7ee..823d64047d01 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4308,10 +4308,6 @@ 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);
@@ -4326,6 +4322,10 @@ 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);
--
2.23.0
next prev parent reply other threads:[~2021-10-04 16:17 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-04 15:59 [PATCH v3 00/52] KVM: PPC: Book3S HV P9: entry/exit optimisations Nicholas Piggin
2021-10-04 15:59 ` [PATCH v3 01/52] powerpc/64s: Remove WORT SPR from POWER9/10 (take 2) Nicholas Piggin
2021-10-04 15:59 ` [PATCH v3 02/52] powerpc/64s: guard optional TIDR SPR with CPU ftr test Nicholas Piggin
2021-10-11 18:44 ` Fabiano Rosas
2021-10-12 2:08 ` Michael Ellerman
2021-10-13 16:51 ` Fabiano Rosas
2021-10-04 16:00 ` [PATCH v3 03/52] KMV: PPC: Book3S HV P9: Use set_dec to set decrementer to host Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 04/52] KVM: PPC: Book3S HV P9: Use host timer accounting to avoid decrementer read Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 05/52] KVM: PPC: Book3S HV P9: Use large decrementer for HDEC Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 06/52] KVM: PPC: Book3S HV P9: Reduce mftb per guest entry/exit Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 07/52] powerpc/time: add API for KVM to re-arm the host timer/decrementer Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 08/52] KVM: PPC: Book3S HV: POWER10 enable HAIL when running radix guests Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 09/52] powerpc/64s: Keep AMOR SPR a constant ~0 at runtime Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 10/52] KVM: PPC: Book3S HV: Don't always save PMU for guest capable of nesting Nicholas Piggin
2021-10-16 12:38 ` Fabiano Rosas
2021-10-20 5:26 ` Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 11/52] powerpc/64s: Always set PMU control registers to frozen/disabled when not in use Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 12/52] powerpc/64s: Implement PMU override command line option Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 13/52] KVM: PPC: Book3S HV P9: Implement PMU save/restore in C Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 14/52] KVM: PPC: Book3S HV P9: Factor PMU save/load into context switch functions Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 15/52] KVM: PPC: Book3S HV P9: Demand fault PMU SPRs when marked not inuse Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 16/52] KVM: PPC: Book3S HV P9: Factor out yield_count increment Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 17/52] KVM: PPC: Book3S HV: CTRL SPR does not require read-modify-write Nicholas Piggin
2021-10-16 12:54 ` Fabiano Rosas
2021-10-04 16:00 ` [PATCH v3 18/52] KVM: PPC: Book3S HV P9: Move SPRG restore to restore_p9_host_os_sprs Nicholas Piggin
2021-10-16 12:59 ` Fabiano Rosas
2021-10-04 16:00 ` [PATCH v3 19/52] KVM: PPC: Book3S HV P9: Reduce mtmsrd instructions required to save host SPRs Nicholas Piggin
2021-10-16 13:45 ` Fabiano Rosas
2021-10-20 5:35 ` Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 20/52] KVM: PPC: Book3S HV P9: Improve mtmsrd scheduling by delaying MSR[EE] disable Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 21/52] KVM: PPC: Book3S HV P9: Add kvmppc_stop_thread to match kvmppc_start_thread Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 22/52] KVM: PPC: Book3S HV: Change dec_expires to be relative to guest timebase Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 23/52] KVM: PPC: Book3S HV P9: Move TB updates Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 24/52] KVM: PPC: Book3S HV P9: Optimise timebase reads Nicholas Piggin
2021-10-04 16:00 ` Nicholas Piggin [this message]
2021-10-04 16:00 ` [PATCH v3 26/52] KVM: PPC: Book3S HV P9: Only execute mtSPR if the value changed Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 27/52] KVM: PPC: Book3S HV P9: Juggle SPR switching around Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 28/52] KVM: PPC: Book3S HV P9: Move vcpu register save/restore into functions Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 29/52] KVM: PPC: Book3S HV P9: Move host OS save/restore functions to built-in Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 30/52] KVM: PPC: Book3S HV P9: Move nested guest entry into its own function Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 31/52] KVM: PPC: Book3S HV P9: Move remaining SPR and MSR access into low level entry Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 32/52] KVM: PPC: Book3S HV P9: Implement TM fastpath for guest entry/exit Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 33/52] KVM: PPC: Book3S HV P9: Switch PMU to guest as late as possible Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 34/52] KVM: PPC: Book3S HV P9: Restrict DSISR canary workaround to processors that require it Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 35/52] KVM: PPC: Book3S HV P9: More SPR speed improvements Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 36/52] KVM: PPC: Book3S HV P9: Demand fault EBB facility registers Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 37/52] KVM: PPC: Book3S HV P9: Demand fault TM " Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 38/52] KVM: PPC: Book3S HV P9: Use Linux SPR save/restore to manage some host SPRs Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 39/52] KVM: PPC: Book3S HV P9: Comment and fix MMU context switching code Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 40/52] KVM: PPC: Book3S HV P9: Test dawr_enabled() before saving host DAWR SPRs Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 41/52] KVM: PPC: Book3S HV P9: Don't restore PSSCR if not needed Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 42/52] KVM: PPC: Book3S HV P9: Avoid tlbsync sequence on radix guest exit Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 43/52] KVM: PPC: Book3S HV Nested: Avoid extra mftb() in nested entry Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 44/52] KVM: PPC: Book3S HV P9: Improve mfmsr performance on entry Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 45/52] KVM: PPC: Book3S HV P9: Optimise hash guest SLB saving Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 46/52] KVM: PPC: Book3S HV P9: Avoid changing MSR[RI] in entry and exit Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 47/52] KVM: PPC: Book3S HV P9: Add unlikely annotation for !mmu_ready Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 48/52] KVM: PPC: Book3S HV P9: Avoid cpu_in_guest atomics on entry and exit Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 49/52] KVM: PPC: Book3S HV P9: Remove most of the vcore logic Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 50/52] KVM: PPC: Book3S HV P9: Tidy kvmppc_create_dtl_entry Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 51/52] KVM: PPC: Book3S HV P9: Stop using vc->dpdes Nicholas Piggin
2021-10-04 16:00 ` [PATCH v3 52/52] KVM: PPC: Book3S HV P9: Remove subcore HMI handling Nicholas Piggin
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