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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 EB709C2B9F7 for ; Wed, 26 May 2021 07:38:06 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9F2F361408 for ; Wed, 26 May 2021 07:38:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F2F361408 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.132360.246913 (Exim 4.92) (envelope-from ) id 1llo6s-0007dQ-5t; Wed, 26 May 2021 07:37:46 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 132360.246913; Wed, 26 May 2021 07:37:46 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1llo6s-0007dJ-2s; Wed, 26 May 2021 07:37:46 +0000 Received: by outflank-mailman (input) for mailman id 132360; Wed, 26 May 2021 07:37:44 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1llo6q-0007dD-8R for xen-devel@lists.xenproject.org; Wed, 26 May 2021 07:37:44 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 8181a2fc-b05d-49af-9a8e-04814d7b975d; Wed, 26 May 2021 07:37:43 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id F14D9ADE2; Wed, 26 May 2021 07:37:41 +0000 (UTC) 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: 8181a2fc-b05d-49af-9a8e-04814d7b975d X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1622014662; h=from:from:reply-to: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=DAgndc2MvHoRJlh2yskU6N8P+M2J8gBju5BwD3ep2bQ=; b=T5e4pvE0nuOx6tpWrbmtSHLUcwGI1ScYp4O4NIn5RsYpGz3nrp9oHO4IjzOKZ9JKKPjnWz HipBuPlDA57ewEEW2Es5glNi4VZCjkc0m19M9mHnCgsqz8m7UPA4Ttw+8o8ltrPHWAzSGu ET8HakWNR6PUEpt7z9CimIVu8o4sGB8= From: Jan Beulich Subject: [PATCH v2] firmware/shim: UNSUPPORTED=n To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , Wei Liu , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , George Dunlap , Dario Faggioli References: <19695ffc-34d8-b682-b092-668f872d4e57@suse.com> Message-ID: <72b98382-34ba-6e9d-c90e-c913dfe66258@suse.com> Date: Wed, 26 May 2021 09:37:37 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <19695ffc-34d8-b682-b092-668f872d4e57@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit We shouldn't default to include any unsupported code in the shim. Mark the setting as off, replacing the ARGO specification. This points out anomalies with the scheduler configuration: Unsupported schedulers better don't default to Y in release builds (like is already the case for ARINC653). Without at least the SCHED_NULL adjustments, the shim would suddenly build with RTDS as its default scheduler. As a result, the SCHED_NULL setting can also be dropped from defconfig. Clearly with the shim defaulting to it, SCHED_NULL must be supported at least there. Signed-off-by: Jan Beulich Acked-by: Roger Pau Monné --- v2: Also drop SCHED_NULL setting from defconfig. Make SCHED_NULL the default when PV_SHIM_EXCLUSIVE. --- I'm certainly open to consider alterations on the sched/Kconfig adjustments, but _something_ needs to be done there. In particular I was puzzled to find the NULL scheduler marked unsupported. Clearly with the shim defaulting to it, it must be supported at least there. In a PV_SHIM (but perhaps !PV_SHIM_EXCLUSIVE) build with the build-time default not being SCHED_NULL, when actually running as shim I can't seem to see how the null scheduler would get chosen as the default nevertheless. Shouldn't this happen (in the absence of a command line override)? --- a/SUPPORT.md +++ b/SUPPORT.md @@ -351,9 +351,10 @@ Currently only single-vcpu domains are s A very simple, very static scheduling policy that always schedules the same vCPU(s) on the same pCPU(s). It is designed for maximum determinism and minimum overhead -on embedded platforms. +on embedded platforms and the x86 PV shim. Status: Experimental + Status, x86/shim: Supported ### NUMA scheduler affinity --- a/xen/arch/x86/configs/pvshim_defconfig +++ b/xen/arch/x86/configs/pvshim_defconfig @@ -6,7 +6,6 @@ CONFIG_PV_SHIM=y CONFIG_PV_SHIM_EXCLUSIVE=y CONFIG_NR_CPUS=32 CONFIG_EXPERT=y -CONFIG_SCHED_NULL=y # Disable features not used by the PV shim # CONFIG_XEN_SHSTK is not set # CONFIG_GRANT_TABLE is not set @@ -15,7 +14,7 @@ CONFIG_SCHED_NULL=y # CONFIG_KEXEC is not set # CONFIG_XENOPROF is not set # CONFIG_XSM is not set -# CONFIG_ARGO is not set +# CONFIG_UNSUPPORTED is not set # CONFIG_SCHED_CREDIT is not set # CONFIG_SCHED_CREDIT2 is not set # CONFIG_SCHED_RTDS is not set --- a/xen/common/sched/Kconfig +++ b/xen/common/sched/Kconfig @@ -16,7 +16,7 @@ config SCHED_CREDIT2 config SCHED_RTDS bool "RTDS scheduler support (UNSUPPORTED)" if UNSUPPORTED - default y + default DEBUG ---help--- The RTDS scheduler is a soft and firm real-time scheduler for multicore, targeted for embedded, automotive, graphics and gaming @@ -31,7 +31,7 @@ config SCHED_ARINC653 config SCHED_NULL bool "Null scheduler support (UNSUPPORTED)" if UNSUPPORTED - default y + default PV_SHIM || DEBUG ---help--- The null scheduler is a static, zero overhead scheduler, for when there always are less vCPUs than pCPUs, typically @@ -39,6 +39,7 @@ config SCHED_NULL choice prompt "Default Scheduler?" + default SCHED_NULL_DEFAULT if PV_SHIM_EXCLUSIVE default SCHED_CREDIT2_DEFAULT config SCHED_CREDIT_DEFAULT