From patchwork Fri Feb 26 22:52:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Stabellini X-Patchwork-Id: 12107441 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 7A927C433E0 for ; Fri, 26 Feb 2021 22:52:29 +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 2902E64EDC for ; Fri, 26 Feb 2021 22:52:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2902E64EDC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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.90615.171602 (Exim 4.92) (envelope-from ) id 1lFlyA-000891-NQ; Fri, 26 Feb 2021 22:52:22 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 90615.171602; Fri, 26 Feb 2021 22:52:22 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lFlyA-00088u-KS; Fri, 26 Feb 2021 22:52:22 +0000 Received: by outflank-mailman (input) for mailman id 90615; Fri, 26 Feb 2021 22:52:21 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lFly9-00088p-30 for xen-devel@lists.xenproject.org; Fri, 26 Feb 2021 22:52:21 +0000 Received: from mail.kernel.org (unknown [198.145.29.99]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 39986784-6fb7-4293-82a7-e79b8de519ac; Fri, 26 Feb 2021 22:52:20 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 6817264EDC; Fri, 26 Feb 2021 22:52:19 +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: 39986784-6fb7-4293-82a7-e79b8de519ac DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614379939; bh=TP3PUri1nqJIGJ0ib6Y6jLpS6FE2eGzTgEFt783zVVs=; h=From:To:Cc:Subject:Date:From; b=noPsku21c4JKET3kCAZnaA7iJuRsJOBLu0bH5RnMQogrUvOwX1IMNXsEizNPf46tg /+EmwMkHJuuKfJL2fC1IoIcDn8+w4KUJSuo2TcUL7BoRGp6EQthXpAGVT4qD0qMJ/b 1bg6NKZ11mroe2IQ3q5AyKmQBKJhtDdKedb5lcj0I1rJxXxTOeBP1ttYeKv9l5lEEw eE9VceFTG92ZZZ8VR6Lem2kW5EimMfnWVfJTnpA7dPoMuWqePNfQqWTzPzSCa5wqhM N9DheWyElw+LBrAs/rTIPGI9jlwij34T1xlMph8YqjzYVWcWKsEJ+Bh1PlpcJwjcJx 5wRpxCubEso2Q== From: Stefano Stabellini To: xen-devel@lists.xenproject.org Cc: sstabellini@kernel.org, Stefano Stabellini , jbeulich@suse.com, andrew.cooper3@citrix.com, julien@xen.org Subject: [PATCH v2] xen: introduce XENFEAT_direct_mapped and XENFEAT_not_direct_mapped Date: Fri, 26 Feb 2021 14:52:17 -0800 Message-Id: <20210226225217.2137-1-sstabellini@kernel.org> X-Mailer: git-send-email 2.17.1 Introduce two feature flags to tell the domain whether it is direct-mapped or not. It allows the guest kernel to make informed decisions on things such as swiotlb-xen enablement. The introduction of both flags (XENFEAT_direct_mapped and XENFEAT_not_direct_mapped) allows the guest kernel to avoid any guesswork if one of the two is present, or fallback to the current checks if neither of them is present. XENFEAT_direct_mapped is always set for not auto-translated guests. For auto-translated guests, only Dom0 on ARM is direct-mapped. Also, see is_domain_direct_mapped() which refers to auto-translated guests: xen/include/asm-arm/domain.h:is_domain_direct_mapped xen/include/asm-x86/domain.h:is_domain_direct_mapped Signed-off-by: Stefano Stabellini CC: jbeulich@suse.com CC: andrew.cooper3@citrix.com CC: julien@xen.org Reviewed-by: Jan Beulich --- Changes in v2: - code style improvements - better comments - better commit message - not auto_translated domains are direct_mapped --- xen/common/kernel.c | 4 ++++ xen/include/public/features.h | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/xen/common/kernel.c b/xen/common/kernel.c index 7a345ae45e..431447326c 100644 --- a/xen/common/kernel.c +++ b/xen/common/kernel.c @@ -560,6 +560,10 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg) (1U << XENFEAT_hvm_callback_vector) | (has_pirq(d) ? (1U << XENFEAT_hvm_pirqs) : 0); #endif + if ( is_domain_direct_mapped(d) || !paging_mode_translate(d) ) + fi.submap |= (1U << XENFEAT_direct_mapped); + else + fi.submap |= (1U << XENFEAT_not_direct_mapped); break; default: return -EINVAL; diff --git a/xen/include/public/features.h b/xen/include/public/features.h index 1613b2aab8..4aebfd359a 100644 --- a/xen/include/public/features.h +++ b/xen/include/public/features.h @@ -114,6 +114,18 @@ */ #define XENFEAT_linux_rsdp_unrestricted 15 +/* + * A direct-mapped (or 1:1 mapped) domain is a domain for which its + * local pages have gfn == mfn. If a domain is direct-mapped, + * XENFEAT_direct_mapped is set; otherwise XENFEAT_not_direct_mapped + * is set. + * + * Not auto_translated domains are always direct-mapped. Also see + * XENFEAT_auto_translated_physmap. + */ +#define XENFEAT_not_direct_mapped 16 +#define XENFEAT_direct_mapped 17 + #define XENFEAT_NR_SUBMAPS 1 #endif /* __XEN_PUBLIC_FEATURES_H__ */