[PATCH v4 52/53] KVM: PPC: Book3S HV P9: Stop using vc->dpdes
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2021-11-23 10:27:23
Subsystem:
kernel virtual machine for powerpc (kvm/powerpc), linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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. 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 2d598291d8cf..214481e5d56d 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c@@ -761,6 +761,8 @@ 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
@@ -2185,8 +2187,10 @@ 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);
@@ -2423,7 +2427,10 @@ 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);
@@ -4491,11 +4498,6 @@ 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 ad70756a777c..7d6d91338c3f 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 6120cdf281b9..72119bc13e1d 100644
--- a/arch/powerpc/kvm/book3s_hv_p9_entry.c
+++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c@@ -780,6 +780,7 @@ 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)
@@ -842,8 +843,10 @@ 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)
@@ -1074,7 +1077,10 @@ 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);
@@ -1136,7 +1142,7 @@ 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