From: Nicholas Piggin <npiggin@gmail.com>
To: kvm-ppc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org, Nicholas Piggin <npiggin@gmail.com>
Subject: [RFC PATCH 5/6] KVM: PPC: Book3S HV P9: Stop using vc->dpdes
Date: Thu, 15 Jul 2021 23:15:17 +1000 [thread overview]
Message-ID: <20210715131518.146917-6-npiggin@gmail.com> (raw)
In-Reply-To: <20210715131518.146917-1-npiggin@gmail.com>
The P9 path uses vc->dpdes only for msgsndp / SMT emulation. This adds
an ordering requirement between vcpu->doorbell_request and vc->dpdes for
no real benefit. Use vcpu->doorbell_request directly.
XXX: verify msgsndp / DPDES emulation works properly.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kvm/book3s_hv.c | 18 ++++++++++--------
arch/powerpc/kvm/book3s_hv_builtin.c | 2 ++
arch/powerpc/kvm/book3s_hv_p9_entry.c | 14 ++++++++++----
3 files changed, 22 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 93ecbc040529..957efde59014 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -766,6 +766,8 @@ static bool kvmppc_doorbell_pending(struct kvm_vcpu *vcpu)
if (vcpu->arch.doorbell_request)
return true;
+ if (cpu_has_feature(CPU_FTR_ARCH_300))
+ return false;
/*
* Ensure that the read of vcore->dpdes comes after the read
* of vcpu->doorbell_request. This barrier matches the
@@ -2165,8 +2167,10 @@ static int kvmppc_get_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
* either vcore->dpdes or doorbell_request.
* On POWER8, doorbell_request is 0.
*/
- *val = get_reg_val(id, vcpu->arch.vcore->dpdes |
- vcpu->arch.doorbell_request);
+ if (cpu_has_feature(CPU_FTR_ARCH_300))
+ *val = get_reg_val(id, vcpu->arch.doorbell_request);
+ else
+ *val = get_reg_val(id, vcpu->arch.vcore->dpdes);
break;
case KVM_REG_PPC_VTB:
*val = get_reg_val(id, vcpu->arch.vcore->vtb);
@@ -2403,7 +2407,10 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
vcpu->arch.pspb = set_reg_val(id, *val);
break;
case KVM_REG_PPC_DPDES:
- vcpu->arch.vcore->dpdes = set_reg_val(id, *val);
+ if (cpu_has_feature(CPU_FTR_ARCH_300))
+ vcpu->arch.doorbell_request = set_reg_val(id, *val) & 1;
+ else
+ vcpu->arch.vcore->dpdes = set_reg_val(id, *val);
break;
case KVM_REG_PPC_VTB:
vcpu->arch.vcore->vtb = set_reg_val(id, *val);
@@ -4431,11 +4438,6 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
if (!nested) {
kvmppc_core_prepare_to_enter(vcpu);
- if (vcpu->arch.doorbell_request) {
- vc->dpdes = 1;
- smp_wmb();
- vcpu->arch.doorbell_request = 0;
- }
if (test_bit(BOOK3S_IRQPRIO_EXTERNAL,
&vcpu->arch.pending_exceptions))
lpcr |= LPCR_MER;
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index be8ef1c5b1bf..9d24f4472b42 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -649,6 +649,8 @@ void kvmppc_guest_entry_inject_int(struct kvm_vcpu *vcpu)
int ext;
unsigned long lpcr;
+ WARN_ON_ONCE(cpu_has_feature(CPU_FTR_ARCH_300));
+
/* Insert EXTERNAL bit into LPCR at the MER bit position */
ext = (vcpu->arch.pending_exceptions >> BOOK3S_IRQPRIO_EXTERNAL) & 1;
lpcr = mfspr(SPRN_LPCR);
diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c
index 82dac23cc678..44150a29f6e0 100644
--- a/arch/powerpc/kvm/book3s_hv_p9_entry.c
+++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c
@@ -677,6 +677,7 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
unsigned long host_pidr;
unsigned long host_dawr1;
unsigned long host_dawrx1;
+ unsigned long dpdes;
hdec = time_limit - *tb;
if (hdec < 0)
@@ -736,8 +737,10 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
if (vc->pcr)
mtspr(SPRN_PCR, vc->pcr | PCR_MASK);
- if (vc->dpdes)
- mtspr(SPRN_DPDES, vc->dpdes);
+ if (vcpu->arch.doorbell_request) {
+ vcpu->arch.doorbell_request = 0;
+ mtspr(SPRN_DPDES, 1);
+ }
if (dawr_enabled()) {
if (vcpu->arch.dawr0 != host_dawr0)
@@ -968,7 +971,10 @@ 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);
+ dpdes = mfspr(SPRN_DPDES);
+ if (dpdes)
+ vcpu->arch.doorbell_request = 1;
+
vc->vtb = mfspr(SPRN_VTB);
dec = mfspr(SPRN_DEC);
@@ -1030,7 +1036,7 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
}
}
- if (vc->dpdes)
+ if (dpdes)
mtspr(SPRN_DPDES, 0);
if (vc->pcr)
mtspr(SPRN_PCR, PCR_MASK);
--
2.23.0
next prev parent reply other threads:[~2021-07-15 13:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-15 13:15 [RFC PATCH 0/6] KVM: PPC: Book3S HV P9: Reduce guest entry/exit Nicholas Piggin
2021-07-15 13:15 ` [RFC PATCH 1/6] KVM: PPC: Book3S HV P9: Add unlikely annotation for !mmu_ready Nicholas Piggin
2021-07-15 13:15 ` [RFC PATCH 2/6] KVM: PPC: Book3S HV P9: Avoid cpu_in_guest atomics on entry and exit Nicholas Piggin
2021-07-15 13:15 ` [RFC PATCH 3/6] KVM: PPC: Book3S HV P9: Remove most of the vcore logic Nicholas Piggin
2021-07-15 13:15 ` [RFC PATCH 4/6] KVM: PPC: Book3S HV P9: Tidy kvmppc_create_dtl_entry Nicholas Piggin
2021-07-15 13:15 ` Nicholas Piggin [this message]
2021-07-15 13:15 ` [RFC PATCH 6/6] KVM: PPC: Book3S HV P9: Remove subcore HMI handling Nicholas Piggin
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