From patchwork Fri Feb 3 08:22:28 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 723466 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3vF94c6nqZz9s7D for ; Fri, 3 Feb 2017 19:28:48 +1100 (AEDT) Received: from localhost ([::1]:60773 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cZZEc-0002YX-DT for incoming@patchwork.ozlabs.org; Fri, 03 Feb 2017 03:28:46 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59448) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cZZ9H-000638-2b for qemu-devel@nongnu.org; Fri, 03 Feb 2017 03:23:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cZZ9D-0004WX-W1 for qemu-devel@nongnu.org; Fri, 03 Feb 2017 03:23:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54968) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cZZ9D-0004WJ-N5 for qemu-devel@nongnu.org; Fri, 03 Feb 2017 03:23:11 -0500 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DDF844E4C8; Fri, 3 Feb 2017 08:23:11 +0000 (UTC) Received: from pxdev.xzpeter.org.com (ovpn-8-19.pek2.redhat.com [10.72.8.19]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v138MwkU005045; Fri, 3 Feb 2017 03:23:07 -0500 From: Peter Xu To: qemu-devel@nongnu.org Date: Fri, 3 Feb 2017 16:22:28 +0800 Message-Id: <1486110164-13797-3-git-send-email-peterx@redhat.com> In-Reply-To: <1486110164-13797-1-git-send-email-peterx@redhat.com> References: <1486110164-13797-1-git-send-email-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 03 Feb 2017 08:23:11 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v6 02/18] vfio: introduce vfio_get_vaddr() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tianyu.lan@intel.com, kevin.tian@intel.com, mst@redhat.com, jan.kiszka@siemens.com, jasowang@redhat.com, peterx@redhat.com, alex.williamson@redhat.com, bd.aviv@gmail.com, David Gibson Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" A cleanup for vfio_iommu_map_notify(). Now we will fetch vaddr even if the operation is unmap, but it won't hurt much. One thing to mention is that we need the RCU read lock to protect the whole translation and map/unmap procedure. Signed-off-by: Peter Xu Acked-by: Alex Williamson Reviewed-by: David Gibson --- hw/vfio/common.c | 65 +++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 45 insertions(+), 20 deletions(-) diff --git a/hw/vfio/common.c b/hw/vfio/common.c index 174f351..42c4790 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -294,54 +294,79 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section) section->offset_within_address_space & (1ULL << 63); } -static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) +/* Called with rcu_read_lock held. */ +static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr, + bool *read_only) { - VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n); - VFIOContainer *container = giommu->container; - hwaddr iova = iotlb->iova + giommu->iommu_offset; MemoryRegion *mr; hwaddr xlat; hwaddr len = iotlb->addr_mask + 1; - void *vaddr; - int ret; - - trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP", - iova, iova + iotlb->addr_mask); - - if (iotlb->target_as != &address_space_memory) { - error_report("Wrong target AS \"%s\", only system memory is allowed", - iotlb->target_as->name ? iotlb->target_as->name : "none"); - return; - } + bool writable = iotlb->perm & IOMMU_WO; /* * The IOMMU TLB entry we have just covers translation through * this IOMMU to its immediate target. We need to translate * it the rest of the way through to memory. */ - rcu_read_lock(); mr = address_space_translate(&address_space_memory, iotlb->translated_addr, - &xlat, &len, iotlb->perm & IOMMU_WO); + &xlat, &len, writable); if (!memory_region_is_ram(mr)) { error_report("iommu map to non memory area %"HWADDR_PRIx"", xlat); - goto out; + return false; } + /* * Translation truncates length to the IOMMU page size, * check that it did not truncate too much. */ if (len & iotlb->addr_mask) { error_report("iommu has granularity incompatible with target AS"); + return false; + } + + *vaddr = memory_region_get_ram_ptr(mr) + xlat; + *read_only = !writable || mr->readonly; + + return true; +} + +static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) +{ + VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n); + VFIOContainer *container = giommu->container; + hwaddr iova = iotlb->iova + giommu->iommu_offset; + bool read_only; + void *vaddr; + int ret; + + trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP", + iova, iova + iotlb->addr_mask); + + if (iotlb->target_as != &address_space_memory) { + error_report("Wrong target AS \"%s\", only system memory is allowed", + iotlb->target_as->name ? iotlb->target_as->name : "none"); + return; + } + + rcu_read_lock(); + + if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) { goto out; } if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) { - vaddr = memory_region_get_ram_ptr(mr) + xlat; + /* + * vaddr is only valid until rcu_read_unlock(). But after + * vfio_dma_map has set up the mapping the pages will be + * pinned by the kernel. This makes sure that the RAM backend + * of vaddr will always be there, even if the memory object is + * destroyed and its backing memory munmap-ed. + */ ret = vfio_dma_map(container, iova, iotlb->addr_mask + 1, vaddr, - !(iotlb->perm & IOMMU_WO) || mr->readonly); + read_only); if (ret) { error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", " "0x%"HWADDR_PRIx", %p) = %d (%m)",