From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C708C46460 for ; Thu, 9 Aug 2018 07:20:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A44EE21C3C for ; Thu, 9 Aug 2018 07:20:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A44EE21C3C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728545AbeHIJoC (ORCPT ); Thu, 9 Aug 2018 05:44:02 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:46398 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727689AbeHIJoB (ORCPT ); Thu, 9 Aug 2018 05:44:01 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5F738402312B; Thu, 9 Aug 2018 07:20:30 +0000 (UTC) Received: from [10.36.117.92] (ovpn-117-92.ams2.redhat.com [10.36.117.92]) by smtp.corp.redhat.com (Postfix) with ESMTP id EE71B10B7CB5; Thu, 9 Aug 2018 07:20:28 +0000 (UTC) Subject: Re: [PATCH RFC 1/2] KVM: s390: vsie: simulate VCPU SIE entry/exit To: linux-kernel@vger.kernel.org Cc: linux-s390@vger.kernel.org, Heiko Carstens , Martin Schwidefsky , Cornelia Huck , Janosch Frank , Christian Borntraeger , Pierre Morel References: <20180807125131.3606-1-david@redhat.com> <20180807125131.3606-2-david@redhat.com> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: Date: Thu, 9 Aug 2018 09:20:28 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180807125131.3606-2-david@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Thu, 09 Aug 2018 07:20:30 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Thu, 09 Aug 2018 07:20:30 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'david@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07.08.2018 14:51, David Hildenbrand wrote: > VCPU requests and VCPU blocking right now don't take care of the vSIE > (as it was not necessary until now). But we want to have VCPU requests > that will also be handled before running the vSIE again. > > So let's simulate a SIE entry when entering the vSIE loop and check > for PROG_ flags. The existing infrastructure (e.g. exit_sie()) will then > detect that the SIE (in form of the vSIE execution loop) is running and > properly kick the vSIE CPU, resulting in it leaving the vSIE loop and > therefore the vSIE interception handler, allowing it to handle VCPU > requests. > > E.g. if we want to modify the crycb of the VCPU and make sure that any > masks also get applied to the VSIE crycb shadow (which uses masks from the > VCPU crycb), we will need a way to hinder the vSIE from running and make > sure to process the updated crycb before reentering the vSIE again. > > Signed-off-by: David Hildenbrand > --- > arch/s390/kvm/kvm-s390.c | 9 ++++++++- > arch/s390/kvm/kvm-s390.h | 1 + > arch/s390/kvm/vsie.c | 20 ++++++++++++++++++-- > 3 files changed, 27 insertions(+), 3 deletions(-) > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index 91ad4a9425c0..c87734a31fdb 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -2766,18 +2766,25 @@ static void kvm_s390_vcpu_request(struct kvm_vcpu *vcpu) > exit_sie(vcpu); > } > > +bool kvm_s390_vcpu_sie_inhibited(struct kvm_vcpu *vcpu) > +{ > + return atomic_read(&vcpu->arch.sie_block->prog20) & > + (PROG_BLOCK_SIE | PROG_REQUEST); > +} > + > static void kvm_s390_vcpu_request_handled(struct kvm_vcpu *vcpu) > { > atomic_andnot(PROG_REQUEST, &vcpu->arch.sie_block->prog20); > } > > /* > - * Kick a guest cpu out of SIE and wait until SIE is not running. > + * Kick a guest cpu out of (v)SIE and wait until (v)SIE is not running. > * If the CPU is not running (e.g. waiting as idle) the function will > * return immediately. */ > void exit_sie(struct kvm_vcpu *vcpu) > { > kvm_s390_set_cpuflags(vcpu, CPUSTAT_STOP_INT); > + kvm_s390_vsie_kick(vcpu); > while (vcpu->arch.sie_block->prog0c & PROG_IN_SIE) > cpu_relax(); > } > diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h > index 981e3ba97461..1f6e36cdce0d 100644 > --- a/arch/s390/kvm/kvm-s390.h > +++ b/arch/s390/kvm/kvm-s390.h > @@ -290,6 +290,7 @@ void kvm_s390_vcpu_start(struct kvm_vcpu *vcpu); > void kvm_s390_vcpu_stop(struct kvm_vcpu *vcpu); > void kvm_s390_vcpu_block(struct kvm_vcpu *vcpu); > void kvm_s390_vcpu_unblock(struct kvm_vcpu *vcpu); > +bool kvm_s390_vcpu_sie_inhibited(struct kvm_vcpu *vcpu); > void exit_sie(struct kvm_vcpu *vcpu); > void kvm_s390_sync_request(int req, struct kvm_vcpu *vcpu); > int kvm_s390_vcpu_setup_cmma(struct kvm_vcpu *vcpu); > diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c > index 63844b95c22c..faac06886f77 100644 > --- a/arch/s390/kvm/vsie.c > +++ b/arch/s390/kvm/vsie.c > @@ -989,6 +989,17 @@ static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; > int rc = 0; > > + /* > + * Simulate a SIE entry of the VCPU (see sie64a), so VCPU blocking > + * and VCPU requests can hinder the whole vSIE loop from running > + * and lead to an immediate exit. We do it at this point (not > + * earlier), so kvm_s390_vsie_kick() works correctly already. > + */ > + vcpu->arch.sie_block->prog0c |= PROG_IN_SIE; > + barrier(); > + if (kvm_s390_vcpu_sie_inhibited(vcpu)) > + return 0; > + > while (1) { > rc = acquire_gmap_shadow(vcpu, vsie_page); > if (!rc) > @@ -1004,10 +1015,14 @@ static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > if (rc == -EAGAIN) > rc = 0; > if (rc || scb_s->icptcode || signal_pending(current) || > - kvm_s390_vcpu_has_irq(vcpu, 0)) > + kvm_s390_vcpu_has_irq(vcpu, 0) || > + kvm_s390_vcpu_sie_inhibited(vcpu)) > break; > } > > + barrier(); > + vcpu->arch.sie_block->prog0c &= ~PROG_IN_SIE; > + I am thinking about moving this down to the actual sie64 call. We eventually take locks and even call into MM code (to resolve faults) inside do_vsie_run(). I think this extra overhead can be avoided (where any caller - e.g. on prefix unmaps has to wait). -- Thanks, David / dhildenb