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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 08D0CC433EF for ; Wed, 2 Mar 2022 08:15:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=iXJMr2QoQwx9dnn+xUcZVDMUmPMGFgI0+ZJnYfrdou4=; b=CSASyvQVya39+y dwhvqHFryqcnSjo3hr12OBRbTK/q1/7QlIA8s3XN7OrTuIY4zEdziY6u8tIQX2ky4nXUQbiTfIyhM SOLrB/AxY+UnH6BmGvtGFhyPZfDmePvwqNsGBLEFafDyRE0JAqRL/r1nJjGrTn6k/tmVNRYMZlrxJ UTksaaM3684LabZw0dDTLgURiRjehx7Q+n603ok4mEvv6RRL/BGaSH5NSeSbEtaSk8qDWH5sXHKQH G1QX3V6vPB312nV4OOFFqEfcyhzuyQ0YHVT5cPosV8SxxuX0pBGseg9V/ML7We3bTqgj0dbsgg67m YRhr352UA7aytfHWiong==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nPK8l-001p4t-Bb; Wed, 02 Mar 2022 08:15:19 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nPK8Z-001p1z-NJ; Wed, 02 Mar 2022 08:15:09 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 527A368BEB; Wed, 2 Mar 2022 09:15:01 +0100 (CET) Date: Wed, 2 Mar 2022 09:15:00 +0100 From: Christoph Hellwig To: Stefano Stabellini Cc: Christoph Hellwig , iommu@lists.linux-foundation.org, x86@kernel.org, Anshuman Khandual , Tom Lendacky , Konrad Rzeszutek Wilk , Boris Ostrovsky , Juergen Gross , Joerg Roedel , David Woodhouse , Lu Baolu , Robin Murphy , linux-arm-kernel@lists.infradead.org, xen-devel@lists.xenproject.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-hyperv@vger.kernel.org, tboot-devel@lists.sourceforge.net, linux-pci@vger.kernel.org Subject: Re: [PATCH 11/12] swiotlb: merge swiotlb-xen initialization into swiotlb Message-ID: <20220302081500.GB23075@lst.de> References: <20220301105311.885699-1-hch@lst.de> <20220301105311.885699-12-hch@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220302_001507_914555_150B01C2 X-CRM114-Status: GOOD ( 21.84 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Mar 01, 2022 at 06:55:47PM -0800, Stefano Stabellini wrote: > Unrelated to this specific patch series: now that I think about it, if > io_tlb_default_mem.nslabs is already allocated by the time xen_mm_init > is called, wouldn't we potentially have an issue with the GFP flags used > for the earlier allocation (e.g. GFP_DMA32 not used)? Maybe something > for another day. swiotlb_init allocates low memory from meblock, which is roughly equivalent to GFP_DMA allocations, so we'll be fine. > > @@ -143,10 +141,15 @@ static int __init xen_mm_init(void) > > if (!xen_swiotlb_detect()) > > return 0; > > > > - rc = xen_swiotlb_init(); > > /* we can work with the default swiotlb */ > > - if (rc < 0 && rc != -EEXIST) > > - return rc; > > + if (!io_tlb_default_mem.nslabs) { > > + if (!xen_initial_domain()) > > + return -EINVAL; > > I don't think we need this xen_initial_domain() check. It is all > already sorted out by the xen_swiotlb_detect() check above. Is it? static inline int xen_swiotlb_detect(void) { if (!xen_domain()) return 0; if (xen_feature(XENFEAT_direct_mapped)) return 1; /* legacy case */ if (!xen_feature(XENFEAT_not_direct_mapped) && xen_initial_domain()) return 1; return 0; } I think I'd keep it as-is for now, as my planned next step would be to fold xen-swiotlb into swiotlb entirely. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv