From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: Re: [PATCH 05/11] KVM: s390: Support Configuration z/Architecture Mode Date: Mon, 28 Aug 2017 21:42:44 +0200 Message-ID: References: <1503907651-65296-1-git-send-email-borntraeger@de.ibm.com> <1503907651-65296-2-git-send-email-borntraeger@de.ibm.com> <28c5c4be-d07a-a82d-916f-5771759f35f1@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: kvm-owner@vger.kernel.org List-Archive: List-Post: To: Christian Borntraeger , Cornelia Huck Cc: Paolo Bonzini , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , KVM , linux-s390 , "Jason J. Herne" List-ID: On 28.08.2017 21:38, Christian Borntraeger wrote: > > > On 08/28/2017 09:35 PM, Christian Borntraeger wrote: >> >> >> On 08/28/2017 09:27 PM, David Hildenbrand wrote: >>> >>>> rc = handle_sigp_dst(vcpu, order_code, cpu_addr, >>>> diff --git a/arch/s390/tools/gen_facilities.c b/arch/s390/tools/gen_facilities.c >>>> index 025ea20..181db5b 100644 >>>> --- a/arch/s390/tools/gen_facilities.c >>>> +++ b/arch/s390/tools/gen_facilities.c >>>> @@ -80,6 +80,7 @@ static struct facility_def facility_defs[] = { >>>> 78, /* enhanced-DAT 2 */ >>>> 130, /* instruction-execution-protection */ >>>> 131, /* enhanced-SOP 2 and side-effect */ >>>> + 138, /* configuration z/architecture mode (czam) */ >>>> 146, /* msa extension 8 */ >>>> -1 /* END */ >>>> } >>>> >>> >>> Thinking about it, this should be the right thing to do instead of the >>> last hunk: >>> >>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >>> index 84c069afc02f..39115f5a38df 100644 >>> --- a/arch/s390/kvm/kvm-s390.c >>> +++ b/arch/s390/kvm/kvm-s390.c >>> @@ -1927,6 +1927,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned >>> long type) >>> memcpy(kvm->arch.model.fac_list, kvm->arch.model.fac_mask, >>> S390_ARCH_FAC_LIST_SIZE_BYTE); >>> >>> + /* we are always in CZAM mode - even on pre z14 machines */ >>> + set_kvm_facility(kvm->arch.model.fac_mask, 138); >>> + set_kvm_facility(kvm->arch.model.fac_list, 138); >>> + /* we emulate STHYI in kvm */ >>> set_kvm_facility(kvm->arch.model.fac_mask, 74); >>> set_kvm_facility(kvm->arch.model.fac_list, 74); >>> if (MACHINE_HAS_TLB_GUEST) { >>> >>> That would produce consistent results for very old QEMU. >>> >> >> This should be identical as the initial fac_list is populated from the fac_mask, >> which is populated by the facility_defs structure. >> >> [..] >> /* Populate the facility list initially. */ >> kvm->arch.model.fac_list = kvm->arch.sie_page2->fac_list; >> ----> memcpy(kvm->arch.model.fac_list, kvm->arch.model.fac_mask, >> S390_ARCH_FAC_LIST_SIZE_BYTE); >> >> [,..] > > Well not identical. The patch actually enables the czam facility only if the host > hardware while your variant enables it always. Interesting discussion if it matters > if we should enable it on z13, z12 and earlier or not > This is also what we do on the QEMU side and what I meant by "consistent". -- Thanks, David