Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756236AbaKTLux (ORCPT ); Thu, 20 Nov 2014 06:50:53 -0500 Received: from smtp.citrix.com ([66.165.176.89]:2355 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754735AbaKTLug (ORCPT ); Thu, 20 Nov 2014 06:50:36 -0500 X-IronPort-AV: E=Sophos;i="5.07,423,1413244800"; d="scan'208";a="193231392" From: David Vrabel To: CC: David Vrabel , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , , , "Konrad Rzeszutek Wilk" , Boris Ostrovsky , Greg Kroah-Hartman Subject: [PATCHv4 0/4]: dma, x86, xen: reduce SWIOTLB usage in Xen guests Date: Thu, 20 Nov 2014 11:50:21 +0000 Message-ID: <1416484225-28054-1-git-send-email-david.vrabel@citrix.com> X-Mailer: git-send-email 1.7.10.4 MIME-Version: 1.0 Content-Type: text/plain X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On systems where DMA addresses and physical addresses are not 1:1 (such as Xen PV guests), the generic dma_get_required_mask() will not return the correct mask (since it uses max_pfn). Some device drivers (such as mptsas, mpt2sas) use dma_get_required_mask() to set the device's DMA mask to allow them to use only 32-bit DMA addresses in hardware structures. This results in unnecessary use of the SWIOTLB if DMA addresses are more than 32-bits, impacting performance significantly. This series allows Xen PV guests to override the default dma_get_required_mask() with one that calculates the DMA mask from the maximum MFN (and not the PFN). Changes in v4: - Assume 64-bit mask is required. Changes in v3: - fix off-by-one in xen_dma_get_required_mask() - split ia64 changes into separate patch. Changes in v2: - split x86 and xen changes into separate patches David -- 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/