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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 CDE48C43331 for ; Thu, 2 Apr 2020 19:20:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 95E8E206F8 for ; Thu, 2 Apr 2020 19:20:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="d9zsM/xO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389671AbgDBTUe (ORCPT ); Thu, 2 Apr 2020 15:20:34 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:36580 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732600AbgDBTUe (ORCPT ); Thu, 2 Apr 2020 15:20:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585855232; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/Iy3b0tEw0WYsBUVVz0ZsRvSgmOMhz0jgg24jpdOh8c=; b=d9zsM/xOrjKvRSQTZSXJTuXGO3jHFx78RB7u1+l9dKJgTWErfVW0bRpBMSR4wnNzsYLrO9 5P8K/7gQgsl0NbItiCmj22GD51Txjs/Q5h0kb8UeyuhB+DRA8V/rFJf6aox7jyX2UfhGjn dVIaB/l/na5cVXwPCuHcV68AWQ/syPw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-488-l10McgFLN6-PWLYQYVF4GA-1; Thu, 02 Apr 2020 15:20:31 -0400 X-MC-Unique: l10McgFLN6-PWLYQYVF4GA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 27D0818B641A; Thu, 2 Apr 2020 19:20:20 +0000 (UTC) Received: from w520.home (ovpn-112-162.phx2.redhat.com [10.3.112.162]) by smtp.corp.redhat.com (Postfix) with ESMTP id D507C5D9C9; Thu, 2 Apr 2020 19:20:12 +0000 (UTC) Date: Thu, 2 Apr 2020 13:20:12 -0600 From: Alex Williamson To: "Liu, Yi L" Cc: eric.auger@redhat.com, kevin.tian@intel.com, jacob.jun.pan@linux.intel.com, joro@8bytes.org, ashok.raj@intel.com, jun.j.tian@intel.com, yi.y.sun@intel.com, jean-philippe@linaro.org, peterx@redhat.com, iommu@lists.linux-foundation.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, hao.wu@intel.com Subject: Re: [PATCH v1 5/8] vfio/type1: Report 1st-level/stage-1 format to userspace Message-ID: <20200402132012.390a7b54@w520.home> In-Reply-To: <1584880325-10561-6-git-send-email-yi.l.liu@intel.com> References: <1584880325-10561-1-git-send-email-yi.l.liu@intel.com> <1584880325-10561-6-git-send-email-yi.l.liu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 22 Mar 2020 05:32:02 -0700 "Liu, Yi L" wrote: > From: Liu Yi L > > VFIO exposes IOMMU nesting translation (a.k.a dual stage translation) > capability to userspace. Thus applications like QEMU could support > vIOMMU with hardware's nesting translation capability for pass-through > devices. Before setting up nesting translation for pass-through devices, > QEMU and other applications need to learn the supported 1st-lvl/stage-1 > translation structure format like page table format. > > Take vSVA (virtual Shared Virtual Addressing) as an example, to support > vSVA for pass-through devices, QEMU setup nesting translation for pass- > through devices. The guest page table are configured to host as 1st-lvl/ > stage-1 page table. Therefore, guest format should be compatible with > host side. > > This patch reports the supported 1st-lvl/stage-1 page table format on the > current platform to userspace. QEMU and other alike applications should > use this format info when trying to setup IOMMU nesting translation on > host IOMMU. > > Cc: Kevin Tian > CC: Jacob Pan > Cc: Alex Williamson > Cc: Eric Auger > Cc: Jean-Philippe Brucker > Signed-off-by: Liu Yi L > --- > drivers/vfio/vfio_iommu_type1.c | 56 +++++++++++++++++++++++++++++++++++++++++ > include/uapi/linux/vfio.h | 1 + > 2 files changed, 57 insertions(+) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 9aa2a67..82a9e0b 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -2234,11 +2234,66 @@ static int vfio_iommu_type1_pasid_free(struct vfio_iommu *iommu, > return ret; > } > > +static int vfio_iommu_get_stage1_format(struct vfio_iommu *iommu, > + u32 *stage1_format) > +{ > + struct vfio_domain *domain; > + u32 format = 0, tmp_format = 0; > + int ret; > + > + mutex_lock(&iommu->lock); > + if (list_empty(&iommu->domain_list)) { > + mutex_unlock(&iommu->lock); > + return -EINVAL; > + } > + > + list_for_each_entry(domain, &iommu->domain_list, next) { > + if (iommu_domain_get_attr(domain->domain, > + DOMAIN_ATTR_PASID_FORMAT, &format)) { > + ret = -EINVAL; > + format = 0; > + goto out_unlock; > + } > + /* > + * format is always non-zero (the first format is > + * IOMMU_PASID_FORMAT_INTEL_VTD which is 1). For > + * the reason of potential different backed IOMMU > + * formats, here we expect to have identical formats > + * in the domain list, no mixed formats support. > + * return -EINVAL to fail the attempt of setup > + * VFIO_TYPE1_NESTING_IOMMU if non-identical formats > + * are detected. > + */ > + if (tmp_format && tmp_format != format) { > + ret = -EINVAL; > + format = 0; > + goto out_unlock; > + } > + > + tmp_format = format; > + } > + ret = 0; > + > +out_unlock: > + if (format) > + *stage1_format = format; > + mutex_unlock(&iommu->lock); > + return ret; > +} > + > static int vfio_iommu_info_add_nesting_cap(struct vfio_iommu *iommu, > struct vfio_info_cap *caps) > { > struct vfio_info_cap_header *header; > struct vfio_iommu_type1_info_cap_nesting *nesting_cap; > + u32 formats = 0; > + int ret; > + > + ret = vfio_iommu_get_stage1_format(iommu, &formats); > + if (ret) { > + pr_warn("Failed to get stage-1 format\n"); > + return ret; Looks like this generates a warning and causes the iommu_get_info ioctl to fail if the hardware doesn't support the pasid format attribute, or the domain list is empty. This breaks users on existing hardware. > + } > > header = vfio_info_cap_add(caps, sizeof(*nesting_cap), > VFIO_IOMMU_TYPE1_INFO_CAP_NESTING, 1); > @@ -2254,6 +2309,7 @@ static int vfio_iommu_info_add_nesting_cap(struct vfio_iommu *iommu, > /* nesting iommu type supports PASID requests (alloc/free) */ > nesting_cap->nesting_capabilities |= VFIO_IOMMU_PASID_REQS; > } > + nesting_cap->stage1_formats = formats; > > return 0; > } > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index ed9881d..ebeaf3e 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -763,6 +763,7 @@ struct vfio_iommu_type1_info_cap_nesting { > struct vfio_info_cap_header header; > #define VFIO_IOMMU_PASID_REQS (1 << 0) > __u32 nesting_capabilities; > + __u32 stage1_formats; > }; > > #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)