Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752901AbeAQLd5 (ORCPT + 1 other); Wed, 17 Jan 2018 06:33:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60478 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750908AbeAQLdz (ORCPT ); Wed, 17 Jan 2018 06:33:55 -0500 Subject: Re: [PATCH 5/6] KVM: s390: wire up seb feature To: Martin Schwidefsky , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org Cc: Heiko Carstens , Paolo Bonzini , Cornelia Huck , Greg Kroah-Hartman , Jon Masters , Marcus Meissner , Jiri Kosina References: <1516182519-10623-1-git-send-email-schwidefsky@de.ibm.com> <1516182519-10623-6-git-send-email-schwidefsky@de.ibm.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <2fa06836-75f8-9c3f-a5e3-217763f6ff4e@redhat.com> Date: Wed, 17 Jan 2018 12:33:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <1516182519-10623-6-git-send-email-schwidefsky@de.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Wed, 17 Jan 2018 11:33:55 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: > #define ECB_GS 0x40 > #define ECB_TE 0x10 > #define ECB_SRSI 0x04 > diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h > index 38535a57..20b9e9f 100644 > --- a/arch/s390/include/uapi/asm/kvm.h > +++ b/arch/s390/include/uapi/asm/kvm.h > @@ -224,6 +224,7 @@ struct kvm_guest_debug_arch { > #define KVM_SYNC_RICCB (1UL << 7) > #define KVM_SYNC_FPRS (1UL << 8) > #define KVM_SYNC_GSCB (1UL << 9) > +#define KVM_SYNC_SEBC (1UL << 10) > /* length and alignment of the sdnx as a power of two */ > #define SDNXC 8 > #define SDNXL (1UL << SDNXC) > @@ -247,7 +248,8 @@ struct kvm_sync_regs { > }; > __u8 reserved[512]; /* for future vector expansion */ > __u32 fpc; /* valid on KVM_SYNC_VRS or KVM_SYNC_FPRS */ > - __u8 padding1[52]; /* riccb needs to be 64byte aligned */ > + __u8 sebc:1; /* spec blocking */ do you want to define the unused bits as reserved? Nicer to read IMHO (especially also using spaces "sebc : 1") > + __u8 padding1[51]; /* riccb needs to be 64byte aligned */ > __u8 riccb[64]; /* runtime instrumentation controls block */ > __u8 padding2[192]; /* sdnx needs to be 256byte aligned */ > union { > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index 2c93cbb..0c18f73 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -421,6 +421,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_S390_GS: > r = test_facility(133); > break; > + case KVM_CAP_S390_SEB: > + r = test_facility(82); > + break; > default: > r = 0; > } > @@ -2198,6 +2201,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) > kvm_s390_set_prefix(vcpu, 0); > if (test_kvm_facility(vcpu->kvm, 64)) > vcpu->run->kvm_valid_regs |= KVM_SYNC_RICCB; > + if (test_kvm_facility(vcpu->kvm, 82)) > + vcpu->run->kvm_valid_regs |= KVM_SYNC_SEBC; > if (test_kvm_facility(vcpu->kvm, 133)) > vcpu->run->kvm_valid_regs |= KVM_SYNC_GSCB; > /* fprs can be synchronized via vrs, even if the guest has no vx. With > @@ -2339,6 +2344,7 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu) > current->thread.fpu.fpc = 0; > vcpu->arch.sie_block->gbea = 1; > vcpu->arch.sie_block->pp = 0; > + vcpu->arch.sie_block->fpf &= ~FPF_SEBC; > vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID; > kvm_clear_async_pf_completion_queue(vcpu); > if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm)) > @@ -3298,6 +3304,10 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) > vcpu->arch.sie_block->ecd |= ECD_HOSTREGMGMT; > vcpu->arch.gs_enabled = 1; > } > + if (kvm_run->kvm_dirty_regs & KVM_SYNC_SEBC) { We should test for test_facility(82). Otherwise user space can enable undefined bits in the SCB on machines with !facility 82. > + vcpu->arch.sie_block->fpf &= ~FPF_SEBC; > + vcpu->arch.sie_block->fpf |= kvm_run->s.regs.sebc ? FPF_SEBC : 0; > + } > save_access_regs(vcpu->arch.host_acrs); > restore_access_regs(vcpu->run->s.regs.acrs); > /* save host (userspace) fprs/vrs */ > @@ -3344,6 +3354,7 @@ static void store_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) > kvm_run->s.regs.pft = vcpu->arch.pfault_token; > kvm_run->s.regs.pfs = vcpu->arch.pfault_select; > kvm_run->s.regs.pfc = vcpu->arch.pfault_compare; > + kvm_run->s.regs.sebc = (vcpu->arch.sie_block->fpf & FPF_SEBC) == FPF_SEBC; > save_access_regs(vcpu->run->s.regs.acrs); > restore_access_regs(vcpu->arch.host_acrs); > /* Save guest register state */ > diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c > index 5d6ae03..10ea208 100644 > --- a/arch/s390/kvm/vsie.c > +++ b/arch/s390/kvm/vsie.c > @@ -223,6 +223,10 @@ static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > memcpy(scb_o->gcr, scb_s->gcr, 128); > scb_o->pp = scb_s->pp; > > + /* speculative blocking */ This field should only be written back with test_kvm_facility(vcpu->kvm, 82) (no public documentation, this looks like the SIE can modify this field? Triggered by which instruction?) > + scb_o->fpf &= ~FPF_SEBC; > + scb_o->fpf |= scb_s->fpf & FPF_SEBC; > + > /* interrupt intercept */ > switch (scb_s->icptcode) { > case ICPT_PROGI: > @@ -265,6 +269,7 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > scb_s->ecb3 = 0; > scb_s->ecd = 0; > scb_s->fac = 0; > + scb_s->fpf = 0; > > rc = prepare_cpuflags(vcpu, vsie_page); > if (rc) > @@ -324,6 +329,9 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > prefix_unmapped(vsie_page); > scb_s->ecb |= scb_o->ecb & ECB_TE; > } > + /* speculative blocking */ > + if (test_kvm_facility(vcpu->kvm, 82)) > + scb_s->fpf |= scb_o->fpf & FPF_SEBC; > /* SIMD */ > if (test_kvm_facility(vcpu->kvm, 129)) { > scb_s->eca |= scb_o->eca & ECA_VX; -- Thanks, David / dhildenb