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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 3D54BC433DB for ; Thu, 14 Jan 2021 17:33:36 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 CA01D23B31 for ; Thu, 14 Jan 2021 17:33:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA01D23B31 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject: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=DLuxW0a9jv1XXVwLETSzVdQNieCLg2cORCQ01Ik8x1w=; b=EtBWTHOIIIxKVC5QU92WtxlRs fYlnQF68pHoHdpQqVPcChvd25dKEpY+cj42/iwrXcNnNeHRB+1Y+ATXE0K6Xm4FnH5UCgc7/vlo4b A95RVeUVQ9q+cnsDQ5Q3zUx7vtdaC6QyXHY5SSVTZRp97brxjmySjxB7gqFNROzvfp5vfqrRoD/m5 ilxesvhhqME0iro6a37x5fKQTaak0W05zaTpRRJE9zSUIR6k6P/RI11L0xhx10UYyyZmK3sHJQZnx WaGmwL0h8OYBJFeA+3CXkyTHJS6mEicZqv3j1w68+YQivtx+kJIrC+LlluATeUOWaCfKHru1HMRMI NCs8x6Qbw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l06Uu-0003A2-3Y; Thu, 14 Jan 2021 17:33:24 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l06Ur-00038o-Gt for linux-nvme@lists.infradead.org; Thu, 14 Jan 2021 17:33:22 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id ABB1068B02; Thu, 14 Jan 2021 18:33:13 +0100 (CET) Date: Thu, 14 Jan 2021 18:33:13 +0100 From: Christoph Hellwig To: Klaus Jensen Subject: Re: [PATCH] nvme: allow use of cmb on v1.4 controllers Message-ID: <20210114173313.GA31028@lst.de> References: <20210114132441.193782-1-its@irrelevant.dk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210114132441.193782-1-its@irrelevant.dk> 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-20210114_123321_682210_BD873F7E X-CRM114-Status: GOOD ( 17.32 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sagi Grimberg , Klaus Jensen , linux-nvme@lists.infradead.org, Jens Axboe , Keith Busch , Christoph Hellwig Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Jan 14, 2021 at 02:24:41PM +0100, Klaus Jensen wrote: > From: Klaus Jensen > > Since NVMe v1.4 the Controller Memory Buffer must be explicitly enabled > by the host. Thanks, this has been on my TODO list for a while. > + vs = readl(dev->bar + NVME_REG_VS); > + > + if (vs >= NVME_VS(1, 4, 0)) { > + if (!NVME_CAP_CMBS(dev->ctrl.cap)) > + return; We should not check the version here, but the presence of the new register so that controllers claiming an older version complicance that implement the new scheme are supported as well. Given that the old scheme is highly dangerous in virtualized enviroments we should also warn about it and eventually required an explicit opt-in to use it. > + if (vs >= NVME_VS(1, 4, 0)) { > + cmbmsc = pci_resource_start(pdev, bar); > + cmbmsc |= (NVME_CMBMSC_CRE | NVME_CMBMSC_CMSE); > + > + /* > + * Writing the low bits may cause the controller to check the > + * validity of the 52 bit controller base address in the CMBMSC > + * register, so write the high bits first. > + */ > + writel(cmbmsc >> 32, dev->bar + NVME_REG_CMBMSC + 4); > + writel(cmbmsc, dev->bar + NVME_REG_CMBMSC); I think we should just use writeq here, with the hilo wrapper for 32-bit platforms here. The reason why NVMe has so avoided the 64-bit access is for buggy Apple controllers, but they are unlikely to implement CMB. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme