Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753858Ab3IEQwc (ORCPT ); Thu, 5 Sep 2013 12:52:32 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:59675 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753545Ab3IEQwb (ORCPT ); Thu, 5 Sep 2013 12:52:31 -0400 X-IronPort-AV: E=Sophos;i="4.90,848,1371081600"; d="scan'208";a="48569840" Date: Thu, 5 Sep 2013 17:43:33 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Catalin Marinas CC: Stefano Stabellini , "xen-devel@lists.xensource.com" , "Ian.Campbell@citrix.com" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "konrad.wilk@oracle.com" Subject: Re: [PATCH v5 11/13] xen: introduce xen_alloc/free_coherent_pages In-Reply-To: <20130905160905.GI11887@arm.com> Message-ID: References: <1377801154-29215-11-git-send-email-stefano.stabellini@eu.citrix.com> <20130905160905.GI11887@arm.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 874 Lines: 18 On Thu, 5 Sep 2013, Catalin Marinas wrote: > On Thu, Aug 29, 2013 at 07:32:32PM +0100, Stefano Stabellini wrote: > > xen_swiotlb_alloc_coherent needs to allocate a coherent buffer for cpu > > and devices. On native x86 and ARMv8 is sufficient to call > > __get_free_pages in order to get a coherent buffer, while on ARM we need > > to call arm_dma_ops.alloc. > > Don't bet on this for ARMv8. It's not mandated for the architecture, so > at some point some SoC will require non-cacheable buffers for coherency. I see. Would it be better if I implemented xen_alloc_coherent_pages on armv8 by calling arm64_swiotlb_dma_ops.alloc? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/