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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 2C874C4BA24 for ; Thu, 27 Feb 2020 08:12:57 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E92B32467F for ; Thu, 27 Feb 2020 08:12:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HQhaeIAE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E92B32467F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55214 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j7EHw-00008h-5y for qemu-devel@archiver.kernel.org; Thu, 27 Feb 2020 03:12:56 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:38360) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j7EHH-00082g-Ia for qemu-devel@nongnu.org; Thu, 27 Feb 2020 03:12:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j7EHG-0004KC-78 for qemu-devel@nongnu.org; Thu, 27 Feb 2020 03:12:15 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:22199 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j7EHG-0004Js-3W for qemu-devel@nongnu.org; Thu, 27 Feb 2020 03:12:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582791133; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=r658ia3hKmhLXCESVbop3fdvJTntt2g0Jkc99YfoFuA=; b=HQhaeIAENugK7Vz99N6rBQGs4Hyog37+b1GGMktfrCDOCbCmom/UwJayIiKnqBfC/Y6S8S QxJpMnpSioHUKZPuZxmz1k21dCDpv+p12rqI/YJVDgfY76oM36qbvyIEEblvkyENvMzzat /Cbz+fUWwTVXgjqvlmXvrfoEGbCQRcs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-164-IDrerJNNNAe_6QgXFEHMug-1; Thu, 27 Feb 2020 03:12:09 -0500 X-MC-Unique: IDrerJNNNAe_6QgXFEHMug-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A2A04107ACC4; Thu, 27 Feb 2020 08:12:08 +0000 (UTC) Received: from [10.36.116.59] (ovpn-116-59.ams2.redhat.com [10.36.116.59]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DD20B77945; Thu, 27 Feb 2020 08:12:06 +0000 (UTC) Subject: Re: [RFC 2/2] hw/arm/virt: kvm: allow gicv3 by default if host does not support v2 To: Andrew Jones References: <20200226170500.17028-1-eric.auger@redhat.com> <20200226170500.17028-3-eric.auger@redhat.com> <20200226184218.g5id5lnhzowiicxf@kamzik.brq.redhat.com> From: Auger Eric Message-ID: Date: Thu, 27 Feb 2020 09:12:05 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20200226184218.g5id5lnhzowiicxf@kamzik.brq.redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, qemu-arm@nongnu.org, eric.auger.pro@gmail.com, qemu-devel@nongnu.org, maz@kernel.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Drew, On 2/26/20 7:42 PM, Andrew Jones wrote: > On Wed, Feb 26, 2020 at 06:05:00PM +0100, Eric Auger wrote: >> At the moment if the end-user does not specify the gic-version along >> with KVM acceleration, v2 is set by default. However most of the >> systems now have GICv3 and sometimes they do not support GICv2 >> compatibility. In that case we end up with this error: >> >> qemu-system-aarch64: PMU: KVM_SET_DEVICE_ATTR: Invalid argument >> qemu-system-aarch64: failed to set irq for PMU >> and qemu aborts. >> >> This patch keeps the default v2 selection in all cases except >> in the KVM accelerated mode when the host does not support v2. >> This case did not work anyway so we do not break any compatibility. >> Now we get v3 selected in such a case. > >> Also if the end-user explicitly >> sets v2 whereas this latter is not supported, we also are >> informed that v2 is not selected by thos host instead of getting the >> above PMU related message. > > I would change the above to: > > Also, if the end-user explicitly sets v2 and this is not supported by > the host, then the user gets a more informative error message than > the PMU invalid argument message above. Sure > >> >> Signed-off-by: Eric Auger >> Reported-by: Dr. David Alan Gilbert >> --- >> hw/arm/virt.c | 30 ++++++++++++++++++++++++++++++ >> include/hw/arm/virt.h | 1 + >> 2 files changed, 31 insertions(+) >> >> diff --git a/hw/arm/virt.c b/hw/arm/virt.c >> index a196bbf0d5..b37b0c40c1 100644 >> --- a/hw/arm/virt.c >> +++ b/hw/arm/virt.c >> @@ -1554,6 +1554,33 @@ static void machvirt_init(MachineState *machine) >> } >> } >> } >> + } else if (kvm_enabled()) { >> + int probe_bitmap = kvm_arm_vgic_probe(); >> + >> + if (!probe_bitmap) { >> + error_report( >> + "Unable to determine GIC version supported by host"); >> + exit(1); >> + } >> + if (!vms->gic_version_user_selected) { >> + /* >> + * by default v2 is supposed to be chosen: check it is >> + * supported by the host. Otherwise take v3. >> + */ >> + if (probe_bitmap & KVM_ARM_VGIC_V2) { >> + vms->gic_version = 2; >> + } else if (probe_bitmap & KVM_ARM_VGIC_V3) { >> + vms->gic_version = 3; >> + } >> + } else { /* user explicitly set the version to 2 or 3 */ >> + if (vms->gic_version == 2 && !(probe_bitmap & KVM_ARM_VGIC_V2)) { >> + error_report("GICv2 is not supported by the host"); >> + exit(1); >> + } else if (vms->gic_version == 3 && !(probe_bitmap & KVM_ARM_VGIC_V3)) { >> + error_report("GICv3 is not supported by the host"); >> + exit(1); >> + } >> + } >> } >> >> if (!cpu_type_valid(machine->cpu_type)) { >> @@ -1840,6 +1867,7 @@ static void virt_set_gic_version(Object *obj, const char *value, Error **errp) >> { >> VirtMachineState *vms = VIRT_MACHINE(obj); >> >> + vms->gic_version_user_selected = true; >> if (!strcmp(value, "3")) { >> vms->gic_version = 3; >> } else if (!strcmp(value, "2")) { >> @@ -1851,6 +1879,7 @@ static void virt_set_gic_version(Object *obj, const char *value, Error **errp) >> } else { >> error_setg(errp, "Invalid gic-version value"); >> error_append_hint(errp, "Valid values are 3, 2, host, max.\n"); >> + vms->gic_version_user_selected = false; >> } >> } >> >> @@ -2103,6 +2132,7 @@ static void virt_instance_init(Object *obj) >> NULL); >> /* Default GIC type is v2 */ >> vms->gic_version = 2; >> + vms->gic_version_user_selected = false; >> object_property_add_str(obj, "gic-version", virt_get_gic_version, >> virt_set_gic_version, NULL); >> object_property_set_description(obj, "gic-version", >> diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h >> index 71508bf40c..e363cde452 100644 >> --- a/include/hw/arm/virt.h >> +++ b/include/hw/arm/virt.h >> @@ -124,6 +124,7 @@ typedef struct { >> bool its; >> bool virt; >> int32_t gic_version; >> + bool gic_version_user_selected; >> VirtIOMMUType iommu; >> struct arm_boot_info bootinfo; >> MemMapEntry *memmap; >> -- >> 2.20.1 >> >> > > I just noticed that virt_get_gic_version() returns "2" if the user didn't > explicitly request "3". I guess that hasn't been a problem for "max" > and "host" because nobody is looking, at least not until after gic_version > has been fully initialized. It is wrong though (for example, with TCG > "max" should be "3", not "2"). That's correct indeed. Ideally virt_get_gic_version() would always > return what will actually be used by the guest, but maybe pre-init it > could return "max", "host", and "nosel" instead. We could then use the > property value "nosel" in machvirt_init() to determine whether or not the > user provided input, rather than adding gic_version_user_selected. OK I will try to address that as well. I also notice the property description for gic-version misses "max" Thanks Eric > > Thanks, > drew > >