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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 4DFF2C433E0 for ; Thu, 9 Jul 2020 11:21:42 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 EFB9D206DF for ; Thu, 9 Jul 2020 11:21:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="o7Zn13YV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EFB9D206DF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4B2YfD2DwQzDqLH for ; Thu, 9 Jul 2020 21:21:40 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4B2YcD3NSkzDq9C for ; Thu, 9 Jul 2020 21:19:56 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=o7Zn13YV; dkim-atps=neutral Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4B2YcB2P66z9s1x; Thu, 9 Jul 2020 21:19:54 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1594293596; bh=dGEXXZrjz1Z84JNnKjB7T7gvF97Fo/wCVLXC7PO2vWs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=o7Zn13YVTmdArBSvThw2v1J6IuZ1hE7jCtYMdh+DV7rALdtKJLjfVx6/uKpndSluA pAJvJ8/EWrpJT/Emx5EA4eQXTitJpvQ4ZI/NFlfjvHOrtzsR1IZY/xTLg3T2H6i2+Q M1iOD1CYug1qLcaL5ROrabf8tsgP4oRGtWJ9Trg9Y9oF6qHHwAlTddM5nJoc6R/ofs wRQT+VZ4UHFilJ1ggIn+SkhNDzsxu984P3EYCdd6WwShYItX9/H+t9gXn64MS9uiXR 3fo8FwP5YRI/OrFEexPAlkCcKEBYsWfAvXqL0rrwd/RBVoqtOWPGy5eGn1wfU+n0lJ SEcquMooGUoBg== From: Michael Ellerman To: Haren Myneni Subject: Re: [PATCH 1/2] powerpc/vas: Report proper error for address translation failure In-Reply-To: References: Date: Thu, 09 Jul 2020 21:22:10 +1000 Message-ID: <87y2ntue59.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tulioqm@br.ibm.com, abali@us.ibm.com, linuxppc-dev@lists.ozlabs.org, rzinsly@linux.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Haren Myneni writes: > DMA controller uses CC=5 internally for translation fault handling. So > OS should be using CC=250 and should report this error to the user space > when NX encounters address translation failure on the request buffer. That doesn't really explain *why* the OS must use CC=250. Is it documented somewhere that 5 is for hardware use, and 250 is for software? > This patch defines CSB_CC_ADDRESS_TRANSLATION(250) and updates > CSB.CC with this proper error code for user space. We still have: #define CSB_CC_TRANSLATION (5) And it's very unclear where one or the other should be used. Can one or the other get a name that makes the distinction clear. cheers > diff --git a/Documentation/powerpc/vas-api.rst b/Documentation/powerpc/vas-api.rst > index 1217c2f..78627cc 100644 > --- a/Documentation/powerpc/vas-api.rst > +++ b/Documentation/powerpc/vas-api.rst > @@ -213,7 +213,7 @@ request buffers are not in memory. The operating system handles the fault by > updating CSB with the following data: > > csb.flags = CSB_V; > - csb.cc = CSB_CC_TRANSLATION; > + csb.cc = CSB_CC_ADDRESS_TRANSLATION; > csb.ce = CSB_CE_TERMINATION; > csb.address = fault_address; > > diff --git a/arch/powerpc/include/asm/icswx.h b/arch/powerpc/include/asm/icswx.h > index 965b1f3..b1c9a57 100644 > --- a/arch/powerpc/include/asm/icswx.h > +++ b/arch/powerpc/include/asm/icswx.h > @@ -77,6 +77,8 @@ struct coprocessor_completion_block { > #define CSB_CC_CHAIN (37) > #define CSB_CC_SEQUENCE (38) > #define CSB_CC_HW (39) > +/* User space address traslation failure */ > +#define CSB_CC_ADDRESS_TRANSLATION (250) > > #define CSB_SIZE (0x10) > #define CSB_ALIGN CSB_SIZE > diff --git a/arch/powerpc/platforms/powernv/vas-fault.c b/arch/powerpc/platforms/powernv/vas-fault.c > index 266a6ca..33e89d4 100644 > --- a/arch/powerpc/platforms/powernv/vas-fault.c > +++ b/arch/powerpc/platforms/powernv/vas-fault.c > @@ -79,7 +79,7 @@ static void update_csb(struct vas_window *window, > csb_addr = (void __user *)be64_to_cpu(crb->csb_addr); > > memset(&csb, 0, sizeof(csb)); > - csb.cc = CSB_CC_TRANSLATION; > + csb.cc = CSB_CC_ADDRESS_TRANSLATION; > csb.ce = CSB_CE_TERMINATION; > csb.cs = 0; > csb.count = 0; > -- > 1.8.3.1