From 80cd8763388b52fa9129cbb4b57a3615a55afd40 Mon Sep 17 00:00:00 2001 From: Fan Zhang Date: Mon, 15 Aug 2016 04:53:22 +0200 Subject: KVM: s390: lazy enable RI Only enable runtime instrumentation if the guest issues an RI related instruction or if userspace changes the riccb to a valid state. This makes entry/exit a tiny bit faster. Initial patch by Christian Borntraeger Signed-off-by: Fan Zhang Signed-off-by: Christian Borntraeger --- arch/s390/kvm/kvm-s390.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'arch/s390/kvm/kvm-s390.c') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index dead20ae9c00..892abf4653a8 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1938,8 +1938,6 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) vcpu->arch.sie_block->eca |= 1; if (sclp.has_sigpif) vcpu->arch.sie_block->eca |= 0x10000000U; - if (test_kvm_facility(vcpu->kvm, 64)) - vcpu->arch.sie_block->ecb3 |= 0x01; if (test_kvm_facility(vcpu->kvm, 129)) { vcpu->arch.sie_block->eca |= 0x00020000; vcpu->arch.sie_block->ecd |= 0x20000000; @@ -2694,6 +2692,19 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID) kvm_clear_async_pf_completion_queue(vcpu); } + /* + * If userspace sets the riccb (e.g. after migration) to a valid state, + * we should enable RI here instead of doing the lazy enablement. + */ + if ((kvm_run->kvm_dirty_regs & KVM_SYNC_RICCB) && + test_kvm_facility(vcpu->kvm, 64)) { + struct runtime_instr_cb *riccb = + (struct runtime_instr_cb *) &kvm_run->s.regs.riccb; + + if (riccb->valid) + vcpu->arch.sie_block->ecb3 |= 0x01; + } + kvm_run->kvm_dirty_regs = 0; } -- cgit v1.2.3