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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 21D8BC32751 for ; Wed, 31 Jul 2019 10:29:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 03B7E206B8 for ; Wed, 31 Jul 2019 10:29:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387621AbfGaK3C (ORCPT ); Wed, 31 Jul 2019 06:29:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60684 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387399AbfGaK3C (ORCPT ); Wed, 31 Jul 2019 06:29:02 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 44D6EC01DE0D; Wed, 31 Jul 2019 10:29:01 +0000 (UTC) Received: from kamzik.brq.redhat.com (unknown [10.43.2.160]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F173019C70; Wed, 31 Jul 2019 10:28:51 +0000 (UTC) Date: Wed, 31 Jul 2019 12:28:49 +0200 From: Andrew Jones To: Thomas Huth Cc: kvm@vger.kernel.org, Christian Borntraeger , Janosch Frank , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, David Hildenbrand , Cornelia Huck , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Shuah Khan , Peter Xu Subject: Re: [PATCH 1/2] KVM: selftests: Implement ucall() for s390x Message-ID: <20190731102849.x26rdan7cddmpvhe@kamzik.brq.redhat.com> References: <20190730100112.18205-1-thuth@redhat.com> <20190730100112.18205-2-thuth@redhat.com> <20190730104807.7uzuvd52foybakgu@kamzik.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Wed, 31 Jul 2019 10:29:01 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Jul 31, 2019 at 11:43:16AM +0200, Thomas Huth wrote: > On 30/07/2019 12.48, Andrew Jones wrote: > > On Tue, Jul 30, 2019 at 12:01:11PM +0200, Thomas Huth wrote: > >> On s390x, we can neither exit via PIO nor MMIO, but have to use > >> an instruction like DIAGNOSE. While we're at it, rename UCALL_PIO > >> to UCALL_DEFAULT, since PIO only works on x86 anyway, and this > >> way we can re-use the "default" type for the DIAGNOSE exit on s390x. > >> > >> Now that ucall() is implemented, we can use it in the sync_reg_test > >> on s390x, too. > >> > >> Signed-off-by: Thomas Huth > >> --- > >> .../testing/selftests/kvm/include/kvm_util.h | 2 +- > >> tools/testing/selftests/kvm/lib/ucall.c | 34 +++++++++++++++---- > >> .../selftests/kvm/s390x/sync_regs_test.c | 6 ++-- > >> 3 files changed, 32 insertions(+), 10 deletions(-) > >> > >> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h > >> index e0e66b115ef2..c37aea2e33e5 100644 > >> --- a/tools/testing/selftests/kvm/include/kvm_util.h > >> +++ b/tools/testing/selftests/kvm/include/kvm_util.h > >> @@ -167,7 +167,7 @@ int vm_create_device(struct kvm_vm *vm, struct kvm_create_device *cd); > >> > >> /* ucall implementation types */ > >> typedef enum { > >> - UCALL_PIO, > >> + UCALL_DEFAULT, > > > > I'd rather we keep explicit types defined; keep PIO and add DIAG. Then > > we can have > > > > /* Set default ucall types */ > > #if defined(__x86_64__) > > ucall_type = UCALL_PIO; > > #elif defined(__aarch64__) > > ucall_type = UCALL_MMIO; > > ucall_requires_init = true; > > #elif defined(__s390x__) > > ucall_type = UCALL_DIAG; > > #endif > > > > And add an assert in get_ucall() > > > > assert(!ucall_requires_init || ucall_initialized); > > I'm not sure whether I really like that. It's yet another additional > #ifdef block, and yet another variable ... > > What do you think about removing the enum completely and simply code it > directly, without the ucall_type indirection, i.e.: > > void ucall(uint64_t cmd, int nargs, ...) > { > struct ucall uc = { > .cmd = cmd, > }; > va_list va; > int i; > > nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS; > > va_start(va, nargs); > for (i = 0; i < nargs; ++i) > uc.args[i] = va_arg(va, uint64_t); > va_end(va); > > #if defined(__x86_64__) > > /* Exit via PIO */ > asm volatile("in %[port], %%al" > : : [port] "d" (UCALL_PIO_PORT), "D" (&uc) : "rax"); > > #elif defined(__aarch64__) > > *ucall_exit_mmio_addr = (vm_vaddr_t)&uc; > > #elif defined(__s390x__) > > /* Exit via DIAGNOSE 0x501 (normally used for breakpoints) */ > asm volatile ("diag 0,%0,0x501" : : "a"(&uc) : "memory"); > > #endif > } > > I think that's way less confusing than having to understand the meaning > of ucall_type etc. before...? > Sounds good to me. Thanks, drew