From patchwork Wed Jan 29 12:16:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 11356069 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B9423112B for ; Wed, 29 Jan 2020 12:12:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A12A02071E for ; Wed, 29 Jan 2020 12:12:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726749AbgA2MML (ORCPT ); Wed, 29 Jan 2020 07:12:11 -0500 Received: from mga04.intel.com ([192.55.52.120]:15958 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726768AbgA2MLx (ORCPT ); Wed, 29 Jan 2020 07:11:53 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Jan 2020 04:11:53 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,377,1574150400"; d="scan'208";a="314071296" Received: from jacob-builder.jf.intel.com ([10.7.199.155]) by fmsmga001.fm.intel.com with ESMTP; 29 Jan 2020 04:11:53 -0800 From: "Liu, Yi L" To: qemu-devel@nongnu.org, david@gibson.dropbear.id.au, pbonzini@redhat.com, alex.williamson@redhat.com, peterx@redhat.com Cc: mst@redhat.com, eric.auger@redhat.com, kevin.tian@intel.com, yi.l.liu@intel.com, jun.j.tian@intel.com, yi.y.sun@intel.com, kvm@vger.kernel.org, hao.wu@intel.com, Jacob Pan , Yi Sun , Richard Henderson , Eduardo Habkost Subject: [RFC v3 21/25] intel_iommu: do not pass down pasid bind for PASID #0 Date: Wed, 29 Jan 2020 04:16:52 -0800 Message-Id: <1580300216-86172-22-git-send-email-yi.l.liu@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1580300216-86172-1-git-send-email-yi.l.liu@intel.com> References: <1580300216-86172-1-git-send-email-yi.l.liu@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Liu Yi L RID_PASID field was introduced in VT-d 3.0 spec, it is used for DMA requests w/o PASID in scalable mode VT-d. It is also known as IOVA. And in VT-d 3.1 spec, there is definition on it: "Implementations not supporting RID_PASID capability (ECAP_REG.RPS is 0b), use a PASID value of 0 to perform address translation for requests without PASID." This patch adds a check against the PASIDs which are going to be bound to device. For PASID #0, it is not necessary to pass down pasid bind request for it since PASID #0 is used as RID_PASID for DMA requests without pasid. Further reason is current Intel vIOMMU supports gIOVA by shadowing guest 2nd level page table. However, in future, if guest IOMMU driver uses 1st level page table to store IOVA mappings, then guest IOVA support will also be done via nested translation. When gIOVA is over FLPT, then vIOMMU should pass down the pasid bind request for PASID #0 to host, host needs to bind the guest IOVA page table to a proper PASID. e.g PASID value in RID_PASID field for PF/VF if ECAP_REG.RPS is clear or default PASID for ADI (Assignable Device Interface in Scalable IOV solution). IOVA over FLPT support on Intel VT-d: https://lkml.org/lkml/2019/9/23/297 Cc: Kevin Tian Cc: Jacob Pan Cc: Peter Xu Cc: Yi Sun Cc: Paolo Bonzini Cc: Richard Henderson Cc: Eduardo Habkost Signed-off-by: Liu Yi L --- hw/i386/intel_iommu.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index 6422add..a511289 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -1883,6 +1883,16 @@ static int vtd_bind_guest_pasid(IntelIOMMUState *s, VTDBus *vtd_bus, struct iommu_gpasid_bind_data *g_bind_data; int ret = -1; + if (pasid < VTD_MIN_HPASID) { + /* + * If pasid < VTD_HPASID_MIN, this pasid is not allocated + * from host. No need to pass down the changes on it to host. + * TODO: when IOVA over FLPT is ready, this switch should be + * refined. + */ + return 0; + } + vtd_icx = vtd_bus->dev_icx[devfn]; if (!vtd_icx) { return ret;