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 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B3A2EC433EF for ; Tue, 18 Jan 2022 08:58:38 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.258405.444948 (Exim 4.92) (envelope-from ) id 1n9kJl-0001Vg-2S; Tue, 18 Jan 2022 08:58:17 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 258405.444948; Tue, 18 Jan 2022 08:58:17 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1n9kJk-0001VZ-Vk; Tue, 18 Jan 2022 08:58:16 +0000 Received: by outflank-mailman (input) for mailman id 258405; Tue, 18 Jan 2022 08:58:15 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1n9kJi-0001VT-Vp for xen-devel@lists.xenproject.org; Tue, 18 Jan 2022 08:58:15 +0000 Received: from mail-lf1-x130.google.com (mail-lf1-x130.google.com [2a00:1450:4864:20::130]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id c4e5e075-783c-11ec-a115-11989b9578b4; Tue, 18 Jan 2022 09:58:13 +0100 (CET) Received: by mail-lf1-x130.google.com with SMTP id x11so42093984lfa.2 for ; Tue, 18 Jan 2022 00:58:13 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: c4e5e075-783c-11ec-a115-11989b9578b4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=cbbC7njoQiCI+pJ3A+jBYzdVhH+bdsBlJDpCjJipZ1k=; b=DL9w/tbX2EpUxLZUWcvEeG+GisPJZHxbXfV4fVea40a2jU1MgQa/Ay/asBpuOkD0/K P3rpL/65TSJjZH7I8wzT0ZCtZ73a+Y7fPQeeS6ay7xGy6O+Xxs569oYrJ0ESshUOWdZ6 dP9JysU/njkBnlLNq8Me6PxrLNEkDp9Ua+nmUP8eU3kfsPMT/DQLbS21eHGab0KMsVpv iiG2y/17J+CC5f8GiE9Bv2QG2crpgc9daHCpSVoF/699MvdiIherWn3oWbanH8guFi8L NvxLsKi+mkqM/UVbVtlPcwSCuol0iTfSVlH0Sf918r+GjYetplNHEqz8dVJpSUdNaiHE fR8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=cbbC7njoQiCI+pJ3A+jBYzdVhH+bdsBlJDpCjJipZ1k=; b=bQcG/aRYlOg4GkuFTK1cQOwg6iNC0o7mvGMHlRwoStvFzK+ddXcxWjd5M114rJcGV0 tXJVPQ/7t2BXjAdwWc5+9UiZhqhrDt7DvITU5G3M0URhECySdKxbl4Z7sWtX4dISA9BB W5Rnei92eRcMwzWegy6c574lNrkukKVgidF4X20+Xg3GeFl6NQ2o+Vat4RqXZztaiR9a 5tCgvpWUkni3HoH3SqQ+QYJAVUNwyyA+hSQIV7JUUmdd/KqWuN2uY2suzzMwTBHb4Kyv DpYIAf3/exk7RubNiQVAOLI7IMfmc7Twa24vSW+DjhkJszi6t2j5LpA8SbWP2fO2t7UT DL1g== X-Gm-Message-State: AOAM530xZQRLHPul6p7UZC66DyT3vjr/YoN5uio8A3R82fcC31wWoWuH IM08pJlCnv4SYI0g64QXGOJ5cnv8MjQ7vsM0Fas= X-Google-Smtp-Source: ABdhPJxf7E4NO8+vtFSE+kHcSeuGHH3g4PAROZ0XsvhLUznbXvda0HMZLAfNtDSxoYVJ/t1GkRSUaAM5VGijcqvh+Y0= X-Received: by 2002:a05:6512:400b:: with SMTP id br11mr18979675lfb.108.1642496293549; Tue, 18 Jan 2022 00:58:13 -0800 (PST) MIME-Version: 1.0 References: <20220117064003.3367188-1-gengdongjiu1@gmail.com> <2a1a0dd5-b8a7-8072-2961-b1fbe9ec746a@xen.org> <9A7FAD16-3D4A-4C22-8288-A4719A993CDD@arm.com> In-Reply-To: <9A7FAD16-3D4A-4C22-8288-A4719A993CDD@arm.com> From: Dongjiu Geng Date: Tue, 18 Jan 2022 16:58:03 +0800 Message-ID: Subject: Re: [PATCH v4] xen/arm: Allow QEMU platform to be built with GICv2 To: Bertrand Marquis Cc: Julien Grall , Stefano Stabellini , Volodymyr Babchuk , xen-devel Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Bertrand Marquis =E4=BA=8E2022=E5=B9=B41=E6=9C= =8818=E6=97=A5=E5=91=A8=E4=BA=8C 16:48=E5=86=99=E9=81=93=EF=BC=9A > > Hi Dongju, > > > On 18 Jan 2022, at 08:45, Dongjiu Geng wrote: > > > > Julien Grall =E4=BA=8E2022=E5=B9=B41=E6=9C=8817=E6=97= =A5=E5=91=A8=E4=B8=80 22:16=E5=86=99=E9=81=93=EF=BC=9A > >> > >> Hi, > >> > >> On 17/01/2022 10:40, Dongjiu Geng wrote: > >>> It turns out that QEMU has been supporting GICv2 virtualization since > >>> v3.1.0. So remove the dependencies on GICv3. > >> > >> > >> Technically, the current form of CONFIG_QEMU allows the same binary to > >> boot on QEMU with GICv2 or GICv3. > >> > >>> If we want to use GICv3, > >>> we can select the QEMU_LEGACY configuration. > >> > >> AFAIK, GICv3 is not a legacy feature... So it feels a bit odd to name = it > >> like that (see more below). > > > > Legacy means QEMU platform only supports GICV3, now it can support > > both GICv2 and GICv3. The scope of support has been expanded > > Not mean GICv3 is a legacy feature. > > You might be misleading a bit here. > In the current configuration, Xen support GICv2, GICv3 and vgic. > The only thing not supported is actually the new VGIC but this is an unsu= pported feature not fully functional which shall be used with caution. > > What issue exactly do you have in Qemu configured for gicv2 when you use = the default configuration ? I want to use NEW_VGIC with GICv2, but QEMU only select GICV3, when GICv3 is select, the NEW_VGIC can not be used. I try the NEW_VGIC with GICv2, not found issue. so I want to remove this limitation. If you think we should not support NEW_VGIC feature, we can ignore this patch. thanks! > > Cheers > Bertrand > > > > >> > >>> > >>> Signed-off-by: Dongjiu Geng > >>> --- > >>> xen/arch/arm/platforms/Kconfig | 10 +++++++++- > >>> 1 file changed, 9 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/xen/arch/arm/platforms/Kconfig b/xen/arch/arm/platforms/= Kconfig > >>> index c93a6b2756..41e82a42ee 100644 > >>> --- a/xen/arch/arm/platforms/Kconfig > >>> +++ b/xen/arch/arm/platforms/Kconfig > >>> @@ -13,7 +13,15 @@ config ALL_PLAT > >>> automatically select any of the related drivers. > >>> > >>> config QEMU > >>> - bool "QEMU aarch virt machine support" > >>> + bool "QEMU aarch virt machine support >=3D v3.1.0" > >> > >> This is a bit misleading. A user may select this thinking that this wi= ll > >> select GICv3. However, this will not. > >> > >> This also raises the question of what is the default GIC version in QE= MU > >> (i.e. if you don't pass anything on the command line)? If this is GICv= 3, > >> then I am afraid that this patch would be a no-go for me. > >> > >> Looking at overall discussion, you seem to push the patch only to allo= w > >> building a tiny Xen for QEMU and the new vGIC. > >> > >> The default Xen (i.e. make defconfig) will also work on QEMU. Given th= at > >> the new vGIC is a still in development, I am seriously considering to > >> say that if you want to try it then you have to use the default > >> configuration. > >> > >> @Dongjiu, is there any reason why you want to use the tiny QEMU config > >> rather than the default configuration? > > > > Hi Julien, thanks for the reply, I do not use the tiny QEMU config. I > > used the default configuration and selected the platform as QEMU. > > But QEMU platform only slects GICV3, so I submit this patch to remove > > the limitation because I want to use VGIC. VGIC can already support > > GICv2 now. > > > >> > >> @Bertrand, @Stefano, what do you think? > >> > >> Cheers, > >> > >> -- > >> Julien Grall >