From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
Fabiano Rosas <farosas@linux.ibm.com>
Subject: [PATCH v4 17/53] KVM: PPC: Book3S HV: CTRL SPR does not require read-modify-write
Date: Tue, 23 Nov 2021 19:51:55 +1000 [thread overview]
Message-ID: <20211123095231.1036501-18-npiggin@gmail.com> (raw)
In-Reply-To: <20211123095231.1036501-1-npiggin@gmail.com>
Processors that support KVM HV do not require read-modify-write of
the CTRL SPR to set/clear their thread's runlatch. Just write 1 or 0
to it.
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kvm/book3s_hv.c | 2 +-
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 15 ++++++---------
2 files changed, 7 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index bbaf018dcb67..e4fb36871ce4 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4071,7 +4071,7 @@ static void load_spr_state(struct kvm_vcpu *vcpu)
*/
if (!(vcpu->arch.ctrl & 1))
- mtspr(SPRN_CTRLT, mfspr(SPRN_CTRLF) & ~1);
+ mtspr(SPRN_CTRLT, 0);
}
static void store_spr_state(struct kvm_vcpu *vcpu)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index a454d65e6353..be79ae7afdf5 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -781,12 +781,11 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
mtspr SPRN_AMR,r5
mtspr SPRN_UAMOR,r6
- /* Restore state of CTRL run bit; assume 1 on entry */
+ /* Restore state of CTRL run bit; the host currently has it set to 1 */
lwz r5,VCPU_CTRL(r4)
andi. r5,r5,1
bne 4f
- mfspr r6,SPRN_CTRLF
- clrrdi r6,r6,1
+ li r6,0
mtspr SPRN_CTRLT,r6
4:
/* Secondary threads wait for primary to have done partition switch */
@@ -1209,12 +1208,12 @@ guest_bypass:
stw r0, VCPU_CPU(r9)
stw r0, VCPU_THREAD_CPU(r9)
- /* Save guest CTRL register, set runlatch to 1 */
+ /* Save guest CTRL register, set runlatch to 1 if it was clear */
mfspr r6,SPRN_CTRLF
stw r6,VCPU_CTRL(r9)
andi. r0,r6,1
bne 4f
- ori r6,r6,1
+ li r6,1
mtspr SPRN_CTRLT,r6
4:
/*
@@ -2184,8 +2183,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_TM)
* Also clear the runlatch bit before napping.
*/
kvm_do_nap:
- mfspr r0, SPRN_CTRLF
- clrrdi r0, r0, 1
+ li r0,0
mtspr SPRN_CTRLT, r0
li r0,1
@@ -2204,8 +2202,7 @@ kvm_nap_sequence: /* desired LPCR value in r5 */
bl isa206_idle_insn_mayloss
- mfspr r0, SPRN_CTRLF
- ori r0, r0, 1
+ li r0,1
mtspr SPRN_CTRLT, r0
mtspr SPRN_SRR1, r3
--
2.23.0
next prev parent reply other threads:[~2021-11-23 10:03 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-23 9:51 [PATCH v4 00/53] KVM: PPC: Book3S HV P9: entry/exit optimisations Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 01/53] powerpc/64s: Remove WORT SPR from POWER9/10 (take 2) Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 02/53] powerpc/64s: guard optional TIDR SPR with CPU ftr test Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 03/53] KMV: PPC: Book3S HV P9: Use set_dec to set decrementer to host Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 04/53] KVM: PPC: Book3S HV P9: Use host timer accounting to avoid decrementer read Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 05/53] KVM: PPC: Book3S HV P9: Use large decrementer for HDEC Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 06/53] KVM: PPC: Book3S HV P9: Reduce mftb per guest entry/exit Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 07/53] powerpc/time: add API for KVM to re-arm the host timer/decrementer Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 08/53] KVM: PPC: Book3S HV: POWER10 enable HAIL when running radix guests Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 09/53] powerpc/64s: Keep AMOR SPR a constant ~0 at runtime Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 10/53] KVM: PPC: Book3S HV: Don't always save PMU for guest capable of nesting Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 11/53] powerpc/64s: Always set PMU control registers to frozen/disabled when not in use Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 12/53] powerpc/64s: Implement PMU override command line option Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 13/53] KVM: PPC: Book3S HV P9: Implement PMU save/restore in C Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 14/53] KVM: PPC: Book3S HV P9: Factor PMU save/load into context switch functions Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 15/53] KVM: PPC: Book3S HV P9: Demand fault PMU SPRs when marked not inuse Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 16/53] KVM: PPC: Book3S HV P9: Factor out yield_count increment Nicholas Piggin
2021-11-23 9:51 ` Nicholas Piggin [this message]
2021-11-23 9:51 ` [PATCH v4 18/53] KVM: PPC: Book3S HV P9: Move SPRG restore to restore_p9_host_os_sprs Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 19/53] KVM: PPC: Book3S HV P9: Reduce mtmsrd instructions required to save host SPRs Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 20/53] KVM: PPC: Book3S HV P9: Improve mtmsrd scheduling by delaying MSR[EE] disable Nicholas Piggin
2021-11-23 9:51 ` [PATCH v4 21/53] KVM: PPC: Book3S HV P9: Add kvmppc_stop_thread to match kvmppc_start_thread Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 22/53] KVM: PPC: Book3S HV: Change dec_expires to be relative to guest timebase Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 23/53] KVM: PPC: Book3S HV P9: Move TB updates Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 24/53] KVM: PPC: Book3S HV P9: Optimise timebase reads Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 25/53] KVM: PPC: Book3S HV P9: Avoid SPR scoreboard stalls Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 26/53] KVM: PPC: Book3S HV P9: Only execute mtSPR if the value changed Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 27/53] KVM: PPC: Book3S HV P9: Juggle SPR switching around Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 28/53] KVM: PPC: Book3S HV P9: Move vcpu register save/restore into functions Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 29/53] KVM: PPC: Book3S HV P9: Move host OS save/restore functions to built-in Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 30/53] KVM: PPC: Book3S HV P9: Move nested guest entry into its own function Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 31/53] KVM: PPC: Book3S HV P9: Move remaining SPR and MSR access into low level entry Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 32/53] KVM: PPC: Book3S HV P9: Implement TM fastpath for guest entry/exit Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 33/53] KVM: PPC: Book3S HV P9: Switch PMU to guest as late as possible Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 34/53] KVM: PPC: Book3S HV P9: Restrict DSISR canary workaround to processors that require it Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 35/53] KVM: PPC: Book3S HV P9: More SPR speed improvements Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 36/53] KVM: PPC: Book3S HV P9: Demand fault EBB facility registers Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 37/53] KVM: PPC: Book3S HV P9: Demand fault TM " Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 38/53] KVM: PPC: Book3S HV P9: Use Linux SPR save/restore to manage some host SPRs Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 39/53] KVM: PPC: Book3S HV P9: Comment and fix MMU context switching code Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 40/53] KVM: PPC: Book3S HV P9: Test dawr_enabled() before saving host DAWR SPRs Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 41/53] KVM: PPC: Book3S HV P9: Don't restore PSSCR if not needed Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 42/53] KVM: PPC: Book3S HV: Split P8 from P9 path guest vCPU TLB flushing Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 43/53] KVM: PPC: Book3S HV P9: Avoid tlbsync sequence on radix guest exit Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 44/53] KVM: PPC: Book3S HV Nested: Avoid extra mftb() in nested entry Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 45/53] KVM: PPC: Book3S HV P9: Improve mfmsr performance on entry Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 46/53] KVM: PPC: Book3S HV P9: Optimise hash guest SLB saving Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 47/53] KVM: PPC: Book3S HV P9: Avoid changing MSR[RI] in entry and exit Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 48/53] KVM: PPC: Book3S HV P9: Add unlikely annotation for !mmu_ready Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 49/53] KVM: PPC: Book3S HV P9: Avoid cpu_in_guest atomics on entry and exit Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 50/53] KVM: PPC: Book3S HV P9: Remove most of the vcore logic Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 51/53] KVM: PPC: Book3S HV P9: Tidy kvmppc_create_dtl_entry Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 52/53] KVM: PPC: Book3S HV P9: Stop using vc->dpdes Nicholas Piggin
2021-11-23 9:52 ` [PATCH v4 53/53] KVM: PPC: Book3S HV P9: Remove subcore HMI handling Nicholas Piggin
2021-11-25 9:38 ` [PATCH v4 00/53] KVM: PPC: Book3S HV P9: entry/exit optimisations Michael Ellerman
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