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 BFE38C4167B for ; Wed, 6 Dec 2023 16:24:07 +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=HjvtLqWsYUjn4WCDAUZdtXu7vkbx2veI+izoWXBX9tE=; b=2QD4UmMH1J6ocM cbAqPG1+BtKuUXRZlPsjBeLAYlUOZ3zqRuo+LF5vK/dPs1my75ErUx8X2s9FkgTjc0+h/wHHxTt2v zpWJyDUVyLDGbfcpfF7ORa42nUZF+nAObvZUGLwOp12+fH0tAg+Mpf6i/715eq5MyPuIYcEZ3l7VA 21yS2hd819Gh6B8mcHxzRKCP8MV+mVdz9LyTAkM6uQzDib3jfxUm1+x55iJCSzoaPYgsYpOvsqppE A1xXx+Mc5fvYaxVjTvRj1i+5BTQptCuJX+qwbCu5YcEzySflbM+ARcHSfTEbTd3+B/1P82ZpePgR0 jLwq0Ot7cyiDRQ2rW03Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rAugV-00AkLC-0F; Wed, 06 Dec 2023 16:23:39 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rAugQ-00AkK9-18 for linux-arm-kernel@lists.infradead.org; Wed, 06 Dec 2023 16:23:36 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by ams.source.kernel.org (Postfix) with ESMTP id 92F49B8214B; Wed, 6 Dec 2023 16:23:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4457C433C8; Wed, 6 Dec 2023 16:23:27 +0000 (UTC) Date: Wed, 6 Dec 2023 16:23:25 +0000 From: Catalin Marinas To: Jason Gunthorpe Cc: Lorenzo Pieralisi , Marc Zyngier , ankita@nvidia.com, Shameerali Kolothum Thodi , oliver.upton@linux.dev, suzuki.poulose@arm.com, yuzenghui@huawei.com, will@kernel.org, ardb@kernel.org, akpm@linux-foundation.org, gshan@redhat.com, aniketa@nvidia.com, cjia@nvidia.com, kwankhede@nvidia.com, targupta@nvidia.com, vsethi@nvidia.com, acurrid@nvidia.com, apopple@nvidia.com, jhubbard@nvidia.com, danw@nvidia.com, mochs@nvidia.com, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 1/1] KVM: arm64: allow the VM to select DEVICE_* and NORMAL_NC for IO memory Message-ID: References: <20231205130517.GD2692119@nvidia.com> <20231205164318.GG2692119@nvidia.com> <20231205194822.GL2692119@nvidia.com> <20231206150556.GQ2692119@nvidia.com> <20231206153809.GS2692119@nvidia.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20231206153809.GS2692119@nvidia.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231206_082335_633746_B3235528 X-CRM114-Status: GOOD ( 16.72 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Dec 06, 2023 at 11:38:09AM -0400, Jason Gunthorpe wrote: > On Wed, Dec 06, 2023 at 04:18:05PM +0100, Lorenzo Pieralisi wrote: > > On Wed, Dec 06, 2023 at 11:05:56AM -0400, Jason Gunthorpe wrote: > > > On Wed, Dec 06, 2023 at 02:49:02PM +0000, Catalin Marinas wrote: > > > > BTW, on those Mellanox devices that require different attributes within > > > > a BAR, do they have a problem with speculative reads causing > > > > side-effects? > > > > > > Yes. We definitely have had that problem in the past on older > > > devices. VFIO must map the BAR using pgprot_device/noncached() into > > > the VMM, no other choice is functionally OK. > > > > Were those BARs tagged as prefetchable or non-prefetchable ? I assume the > > latter but please let me know if I am guessing wrong. > > I don't know it was quite old HW. Probably. > > Just because a BAR is not marked as prefetchable doesn't mean that the > device can't use NORMAL_NC on subsets of it. What about the other way around - would we have a prefetchable BAR that has portions which are unprefetchable? -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel