From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-2.mimecast.com ([205.139.110.61]:23844 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726697AbgAJKgz (ORCPT ); Fri, 10 Jan 2020 05:36:55 -0500 Subject: Re: [PATCH v6] KVM: s390: Add new reset vcpu API References: <20200110101906.54291-1-frankja@linux.ibm.com> From: Thomas Huth Message-ID: <9b9c3e09-e3ec-0ef2-0aef-a31ff34df33b@redhat.com> Date: Fri, 10 Jan 2020 11:36:44 +0100 MIME-Version: 1.0 In-Reply-To: <20200110101906.54291-1-frankja@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Sender: linux-s390-owner@vger.kernel.org List-ID: To: Janosch Frank , kvm@vger.kernel.org Cc: borntraeger@de.ibm.com, linux-s390@vger.kernel.org, david@redhat.com, cohuck@redhat.com On 10/01/2020 11.19, Janosch Frank wrote: > The architecture states that we need to reset local IRQs for all CPU > resets. Because the old reset interface did not support the normal CPU > reset we never did that on a normal reset. >=20 > Let's implement an interface for the missing normal and clear resets > and reset all local IRQs, registers and control structures as stated > in the architecture. >=20 > Userspace might already reset the registers via the vcpu run struct, > but as we need the interface for the interrupt clearing part anyway, > we implement the resets fully and don't rely on userspace to reset the > rest. >=20 > Signed-off-by: Janosch Frank > --- [...] > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index d9e6bf3d54f0..4936f9499291 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -529,6 +529,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, l= ong ext) > case KVM_CAP_S390_CMMA_MIGRATION: > case KVM_CAP_S390_AIS: > case KVM_CAP_S390_AIS_MIGRATION: > + case KVM_CAP_S390_VCPU_RESETS: > r =3D 1; > break; > case KVM_CAP_S390_HPAGE_1M: > @@ -2844,35 +2845,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) > =20 > } > =20 > -static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu) > -{ > - /* this equals initial cpu reset in pop, but we don't switch to ESA *= / > - vcpu->arch.sie_block->gpsw.mask =3D 0UL; > - vcpu->arch.sie_block->gpsw.addr =3D 0UL; > - kvm_s390_set_prefix(vcpu, 0); > - kvm_s390_set_cpu_timer(vcpu, 0); > - vcpu->arch.sie_block->ckc =3D 0UL; > - vcpu->arch.sie_block->todpr =3D 0; > - memset(vcpu->arch.sie_block->gcr, 0, 16 * sizeof(__u64)); > - vcpu->arch.sie_block->gcr[0] =3D CR0_UNUSED_56 | > - CR0_INTERRUPT_KEY_SUBMASK | > - CR0_MEASUREMENT_ALERT_SUBMASK; > - vcpu->arch.sie_block->gcr[14] =3D CR14_UNUSED_32 | > - CR14_UNUSED_33 | > - CR14_EXTERNAL_DAMAGE_SUBMASK; > - /* make sure the new fpc will be lazily loaded */ > - save_fpu_regs(); > - current->thread.fpu.fpc =3D 0; > - vcpu->arch.sie_block->gbea =3D 1; > - vcpu->arch.sie_block->pp =3D 0; > - vcpu->arch.sie_block->fpf &=3D ~FPF_BPBC; > - vcpu->arch.pfault_token =3D KVM_S390_PFAULT_TOKEN_INVALID; > - kvm_clear_async_pf_completion_queue(vcpu); > - if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm)) > - kvm_s390_vcpu_stop(vcpu); > - kvm_s390_clear_local_irqs(vcpu); > -} > - > void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) > { > mutex_lock(&vcpu->kvm->lock); > @@ -3287,10 +3259,78 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(stru= ct kvm_vcpu *vcpu, > return r; > } > =20 > -static int kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu) > +static void kvm_arch_vcpu_ioctl_normal_reset(struct kvm_vcpu *vcpu) > { > - kvm_s390_vcpu_initial_reset(vcpu); > - return 0; > + vcpu->arch.sie_block->gpsw.mask =3D ~PSW_MASK_RI; > + vcpu->arch.pfault_token =3D KVM_S390_PFAULT_TOKEN_INVALID; > + memset(vcpu->run->s.regs.riccb, 0, sizeof(vcpu->run->s.regs.riccb)); > + > + kvm_clear_async_pf_completion_queue(vcpu); > + if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm)) > + kvm_s390_vcpu_stop(vcpu); > + kvm_s390_clear_local_irqs(vcpu); > +} > + > +static void kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu) > +{ > + /* Initial reset is a superset of the normal reset */ > + kvm_arch_vcpu_ioctl_normal_reset(vcpu); > + > + /* this equals initial cpu reset in pop, but we don't switch to ESA *= / > + vcpu->arch.sie_block->gpsw.mask =3D 0UL; > + vcpu->arch.sie_block->gpsw.addr =3D 0UL; > + kvm_s390_set_prefix(vcpu, 0); > + kvm_s390_set_cpu_timer(vcpu, 0); > + vcpu->arch.sie_block->ckc =3D 0UL; > + vcpu->arch.sie_block->todpr =3D 0; > + memset(vcpu->arch.sie_block->gcr, 0, 16 * sizeof(__u64)); > + vcpu->arch.sie_block->gcr[0] =3D CR0_UNUSED_56 | > + CR0_INTERRUPT_KEY_SUBMASK | > + CR0_MEASUREMENT_ALERT_SUBMASK; > + vcpu->arch.sie_block->gcr[14] =3D CR14_UNUSED_32 | > + CR14_UNUSED_33 | > + CR14_EXTERNAL_DAMAGE_SUBMASK; > + /* make sure the new fpc will be lazily loaded */ > + save_fpu_regs(); > + current->thread.fpu.fpc =3D 0; > + vcpu->arch.sie_block->gbea =3D 1; > + vcpu->arch.sie_block->pp =3D 0; > + vcpu->arch.sie_block->fpf &=3D ~FPF_BPBC; > +} > + > +static void kvm_arch_vcpu_ioctl_clear_reset(struct kvm_vcpu *vcpu) > +{ > + struct kvm_sync_regs *regs =3D &vcpu->run->s.regs; > + > + /* Clear reset is a superset of the initial reset */ > + kvm_arch_vcpu_ioctl_normal_reset(vcpu); > + > + memset(®s->gprs, 0, sizeof(regs->gprs)); > + /* > + * Will be picked up via save_fpu_regs() in the initial reset > + * fallthrough. The word "fallthrough" now likely should be removed from the comment. Also, I'm not an expert in this lazy-fpu stuff, but don't you rather have to deal with current->thread.fpu.regs here instead? > + */ > + memset(®s->vrs, 0, sizeof(regs->vrs)); > + memset(®s->acrs, 0, sizeof(regs->acrs)); > + > + regs->etoken =3D 0; > + regs->etoken_extension =3D 0; > + > + memset(®s->gscb, 0, sizeof(regs->gscb)); > + if (MACHINE_HAS_GS) { > + preempt_disable(); > + __ctl_set_bit(2, 4); > + if (current->thread.gs_cb) { > + vcpu->arch.host_gscb =3D current->thread.gs_cb; > + save_gs_cb(vcpu->arch.host_gscb); > + } > + if (vcpu->arch.gs_enabled) { > + current->thread.gs_cb =3D (struct gs_cb *) > + &vcpu->run->s.regs.gscb; > + restore_gs_cb(current->thread.gs_cb); > + } > + preempt_enable(); > + } > } Thomas