From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH v4 26/53] KVM: PPC: Book3S HV P9: Only execute mtSPR if the value changed
Date: Tue, 23 Nov 2021 19:52:04 +1000 [thread overview]
Message-ID: <20211123095231.1036501-27-npiggin@gmail.com> (raw)
In-Reply-To: <20211123095231.1036501-1-npiggin@gmail.com>
Keep better track of the current SPR value in places where
they are to be loaded with a new context, to reduce expensive
mtSPR operations.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kvm/book3s_hv.c | 51 ++++++++++++++++++++++--------------
1 file changed, 31 insertions(+), 20 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 75a674b5cd84..5c44c4ff5d46 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4055,20 +4055,28 @@ static void switch_pmu_to_host(struct kvm_vcpu *vcpu,
}
}
-static void load_spr_state(struct kvm_vcpu *vcpu)
+static void load_spr_state(struct kvm_vcpu *vcpu,
+ struct p9_host_os_sprs *host_os_sprs)
{
- mtspr(SPRN_DSCR, vcpu->arch.dscr);
- mtspr(SPRN_IAMR, vcpu->arch.iamr);
- mtspr(SPRN_PSPB, vcpu->arch.pspb);
- mtspr(SPRN_FSCR, vcpu->arch.fscr);
mtspr(SPRN_TAR, vcpu->arch.tar);
mtspr(SPRN_EBBHR, vcpu->arch.ebbhr);
mtspr(SPRN_EBBRR, vcpu->arch.ebbrr);
mtspr(SPRN_BESCR, vcpu->arch.bescr);
+
if (cpu_has_feature(CPU_FTR_P9_TIDR))
mtspr(SPRN_TIDR, vcpu->arch.tid);
- mtspr(SPRN_AMR, vcpu->arch.amr);
- mtspr(SPRN_UAMOR, vcpu->arch.uamor);
+ if (host_os_sprs->iamr != vcpu->arch.iamr)
+ mtspr(SPRN_IAMR, vcpu->arch.iamr);
+ if (host_os_sprs->amr != vcpu->arch.amr)
+ mtspr(SPRN_AMR, vcpu->arch.amr);
+ if (vcpu->arch.uamor != 0)
+ mtspr(SPRN_UAMOR, vcpu->arch.uamor);
+ if (host_os_sprs->fscr != vcpu->arch.fscr)
+ mtspr(SPRN_FSCR, vcpu->arch.fscr);
+ if (host_os_sprs->dscr != vcpu->arch.dscr)
+ mtspr(SPRN_DSCR, vcpu->arch.dscr);
+ if (vcpu->arch.pspb != 0)
+ mtspr(SPRN_PSPB, vcpu->arch.pspb);
/*
* DAR, DSISR, and for nested HV, SPRGs must be set with MSR[RI]
@@ -4083,20 +4091,21 @@ static void load_spr_state(struct kvm_vcpu *vcpu)
static void store_spr_state(struct kvm_vcpu *vcpu)
{
- vcpu->arch.ctrl = mfspr(SPRN_CTRLF);
-
- vcpu->arch.iamr = mfspr(SPRN_IAMR);
- vcpu->arch.pspb = mfspr(SPRN_PSPB);
- vcpu->arch.fscr = mfspr(SPRN_FSCR);
vcpu->arch.tar = mfspr(SPRN_TAR);
vcpu->arch.ebbhr = mfspr(SPRN_EBBHR);
vcpu->arch.ebbrr = mfspr(SPRN_EBBRR);
vcpu->arch.bescr = mfspr(SPRN_BESCR);
+
if (cpu_has_feature(CPU_FTR_P9_TIDR))
vcpu->arch.tid = mfspr(SPRN_TIDR);
+ vcpu->arch.iamr = mfspr(SPRN_IAMR);
vcpu->arch.amr = mfspr(SPRN_AMR);
vcpu->arch.uamor = mfspr(SPRN_UAMOR);
+ vcpu->arch.fscr = mfspr(SPRN_FSCR);
vcpu->arch.dscr = mfspr(SPRN_DSCR);
+ vcpu->arch.pspb = mfspr(SPRN_PSPB);
+
+ vcpu->arch.ctrl = mfspr(SPRN_CTRLF);
}
static void save_p9_host_os_sprs(struct p9_host_os_sprs *host_os_sprs)
@@ -4107,6 +4116,7 @@ static void save_p9_host_os_sprs(struct p9_host_os_sprs *host_os_sprs)
host_os_sprs->iamr = mfspr(SPRN_IAMR);
host_os_sprs->amr = mfspr(SPRN_AMR);
host_os_sprs->fscr = mfspr(SPRN_FSCR);
+ host_os_sprs->dscr = mfspr(SPRN_DSCR);
}
/* vcpu guest regs must already be saved */
@@ -4115,19 +4125,20 @@ static void restore_p9_host_os_sprs(struct kvm_vcpu *vcpu,
{
mtspr(SPRN_SPRG_VDSO_WRITE, local_paca->sprg_vdso);
- mtspr(SPRN_PSPB, 0);
- mtspr(SPRN_UAMOR, 0);
-
- mtspr(SPRN_DSCR, host_os_sprs->dscr);
if (cpu_has_feature(CPU_FTR_P9_TIDR))
mtspr(SPRN_TIDR, host_os_sprs->tidr);
- mtspr(SPRN_IAMR, host_os_sprs->iamr);
-
+ if (host_os_sprs->iamr != vcpu->arch.iamr)
+ mtspr(SPRN_IAMR, host_os_sprs->iamr);
+ if (vcpu->arch.uamor != 0)
+ mtspr(SPRN_UAMOR, 0);
if (host_os_sprs->amr != vcpu->arch.amr)
mtspr(SPRN_AMR, host_os_sprs->amr);
-
if (host_os_sprs->fscr != vcpu->arch.fscr)
mtspr(SPRN_FSCR, host_os_sprs->fscr);
+ if (host_os_sprs->dscr != vcpu->arch.dscr)
+ mtspr(SPRN_DSCR, host_os_sprs->dscr);
+ if (vcpu->arch.pspb != 0)
+ mtspr(SPRN_PSPB, 0);
/* Save guest CTRL register, set runlatch to 1 */
if (!(vcpu->arch.ctrl & 1))
@@ -4219,7 +4230,7 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit,
#endif
mtspr(SPRN_VRSAVE, vcpu->arch.vrsave);
- load_spr_state(vcpu);
+ load_spr_state(vcpu, &host_os_sprs);
if (kvmhv_on_pseries()) {
/*
--
2.23.0
next prev parent reply other threads:[~2021-11-23 10:09 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 ` [PATCH v4 17/53] KVM: PPC: Book3S HV: CTRL SPR does not require read-modify-write Nicholas Piggin
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 ` Nicholas Piggin [this message]
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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