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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 4CB14C433ED for ; Mon, 3 May 2021 07:02:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18BA0611CB for ; Mon, 3 May 2021 07:02:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232885AbhECHDB (ORCPT ); Mon, 3 May 2021 03:03:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229817AbhECHC7 (ORCPT ); Mon, 3 May 2021 03:02:59 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA487C06174A; Mon, 3 May 2021 00:02:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=EvzK/tNTFu6j7RpqReg+UsePxfTlwWDpS1m4nxob5S8=; b=d+fupqW0bciG3xsylg36LLTQ15 +QOOLEWa0exqDSIyE2RFjDoTQS5TD06FY0/1FfQh1XNyXHeFTsG9tyenVBVIqgjCBGawuG14FPPQb nlgJ4eujI3lzEMR10byAqYaaw88/xqIRqygJ5YIZ9PGkOsxhy0ki3ZQtW3ya69QlCjplaZenO46s3 CkePR34QF23Hm6BAF/3bUu0VKRE3N5IjTHEqDqDYFI3jHmEo9AfrGQSPCIGrZ0Y8/bi+X18cTDSU5 0b538F8+voZe0aZQuAYNWKR2ipPh29rG5HgUm/aggYZDfxdDlS/AZf2JS+8jK3UFDn0+WK/YHAl6N vR5rCHXw==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1ldSaF-00Elgh-Vf; Mon, 03 May 2021 07:01:37 +0000 Date: Mon, 3 May 2021 08:01:35 +0100 From: Christoph Hellwig To: Shanker Donthineni Cc: Marc Zyngier , Alex Williamson , Will Deacon , Catalin Marinas , Christoffer Dall , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Vikram Sethi , Jason Sequeira Subject: Re: [RFC 0/2] [RFC] Honor PCI prefetchable attributes for a virtual machine on ARM64 Message-ID: <20210503070135.GA3515187@infradead.org> References: <20210429162906.32742-1-sdonthineni@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210429162906.32742-1-sdonthineni@nvidia.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 29, 2021 at 11:29:04AM -0500, Shanker Donthineni wrote: > Problem statement: Virtual machine crashes when NVIDIA GPU driver access a prefetchable BAR space due to the unaligned reads/writes for pass-through devices. The same binary works fine as expected in the host kernel. Only one BAR has control & status registers (CSR) and other PCI BARs are marked as prefetchable. NVIDIA GPU driver uses the write-combine feature for mapping the prefetchable BARs to improve performance. This problem applies to all other drivers which want to enable WC. Unless you mean the noveau drivers this simply does not matter. Please don't spam the kernel lists with issues with your broken and license violating drivers.