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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4E767ECAAA1 for ; Sun, 30 Oct 2022 17:36:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1opCDN-0000AS-93; Sun, 30 Oct 2022 13:35:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1opCDJ-00008M-BH for qemu-devel@nongnu.org; Sun, 30 Oct 2022 13:35:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1opCDG-0002rD-60 for qemu-devel@nongnu.org; Sun, 30 Oct 2022 13:35:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667151308; 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=eI1vIpA6G7sTas5c7d7OEXhzlpOHvpGNrmh2edfNaYs=; b=YxvAJ03h2dMLAScOLiklWdUGe4m26ZhvdS+DjCzedsmvJ9Jlrx75tShyOlyu2gOt8zFi4s BiF17Pl52Ksnzug9JQMIGpxl3uvoW2R7AgAC42Zw00TPdTno22djSObinqfVlKW86daDo0 YqTjz3/aAVrx2OR/PkEpOmdqDFowX5I= Received: from mail-il1-f200.google.com (mail-il1-f200.google.com [209.85.166.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-45-fm7FDWDMPu6kI9XPjk8EbA-1; Sun, 30 Oct 2022 13:35:05 -0400 X-MC-Unique: fm7FDWDMPu6kI9XPjk8EbA-1 Received: by mail-il1-f200.google.com with SMTP id s2-20020a056e021a0200b0030087a59cf9so4735923ild.11 for ; Sun, 30 Oct 2022 10:35:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:organization:references :in-reply-to:message-id:subject:cc:to:from:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=eI1vIpA6G7sTas5c7d7OEXhzlpOHvpGNrmh2edfNaYs=; b=bk32hvmkRFboTW8YECjpXp37Fo4qyq6kVJVhpa17Z94IVeWUCMeRObSZJecwdE3sLZ p1KgsTAAcrDpGQdEcHwN2DGyzEy/LIBn3Sra1uQnhB3zaG5VQz3xStunki4QhaHPVq/U 5UtYncjpQdPeJocW6Lb8uc4UKMzBAOCCNNW3GtEsnbkUOQbFpQ24uGRSUK47Gy6Up6bS TorcBoXwpoeu7zMWT0AujB15o+uosugaDPTUqyl/r1kZ37Uhoj/nDjWSwwljV+CrpU/R 7Dd2kQtfF5kZ+78FR0rzusYIKmXle9fA4Bm/8ri0u1AP0vSzc5U4j2iSbvCFsNBSKUIi EO4g== X-Gm-Message-State: ACrzQf1w2aa0IcOqUalixVYP53Q0qbRXmbZjpMUda+wTk/ZVKzoj1ElE qcfdvNJddHtMGmjiMgaAVdMDsB0t5aip6olIcGET7g4HT2h5Ir+aVI1wJrj2dovI5SRJ5znTSA9 TMScIGcWpvNjIirM= X-Received: by 2002:a05:6638:3711:b0:363:a1f2:df4e with SMTP id k17-20020a056638371100b00363a1f2df4emr5258712jav.226.1667151304408; Sun, 30 Oct 2022 10:35:04 -0700 (PDT) X-Google-Smtp-Source: AMsMyM6WATwlvmUYUbyA5RtP1erAy0QrB3X63geoPDBJDNjj7o/HJurVgzIfkIUfBLf3qoxCuXqdSA== X-Received: by 2002:a05:6638:3711:b0:363:a1f2:df4e with SMTP id k17-20020a056638371100b00363a1f2df4emr5258704jav.226.1667151304124; Sun, 30 Oct 2022 10:35:04 -0700 (PDT) Received: from redhat.com ([38.15.36.239]) by smtp.gmail.com with ESMTPSA id w16-20020a056e0213f000b002faecf63c48sm1711709ilj.79.2022.10.30.10.35.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Oct 2022 10:35:03 -0700 (PDT) Date: Sun, 30 Oct 2022 11:35:02 -0600 From: Alex Williamson To: Cindy Lu Cc: jasowang@redhat.com, mst@redhat.com, pbonzini@redhat.com, peterx@redhat.com, david@redhat.com, f4bug@amsat.org, sgarzare@redhat.com, qemu-devel@nongnu.org Subject: Re: [PATCH v7 1/2] vfio: move function vfio_get_xlat_addr() to memory.c Message-ID: <20221030113502.5c2e5e63.alex.williamson@redhat.com> In-Reply-To: <20221030164539.1374058-2-lulu@redhat.com> References: <20221030164539.1374058-1-lulu@redhat.com> <20221030164539.1374058-2-lulu@redhat.com> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=170.10.129.124; envelope-from=alex.williamson@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.055, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Qemu-devel" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, 31 Oct 2022 00:45:38 +0800 Cindy Lu wrote: > - Move the function vfio_get_xlat_addr to softmmu/memory.c, and > =C2=A0 change the name to memory_get_xlat_addr(). So we can use this > =C2=A0 function on other devices, such as vDPA device. > - Add a new bool arg in this function, which shows whether the memory is > =C2=A0 backed by a discard manager. So the device can have its own warnin= g. >=20 > Signed-off-by: Cindy Lu > --- > hw/vfio/common.c | 107 +++++++++++------------------------------- > include/exec/memory.h | 4 ++ > softmmu/memory.c | 72 ++++++++++++++++++++++++++++ > 3 files changed, 104 insertions(+), 79 deletions(-) >=20 > diff --git a/hw/vfio/common.c b/hw/vfio/common.c > index ace9562a9b..a934262f39 100644 > --- a/hw/vfio/common.c > +++ b/hw/vfio/common.c > @@ -573,61 +573,20 @@ static bool vfio_listener_skipped_section(MemoryReg= ionSection *section) > */ > section->offset_within_address_space & (1ULL << 63); > } > - > -/* Called with rcu_read_lock held. */ > -static bool vfio_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr, > - ram_addr_t *ram_addr, bool *read_only) > +static inline void vfio_mr_discard_manager_warn(bool mr_has_discard_mana= ger) > { > - MemoryRegion *mr; > - hwaddr xlat; > - hwaddr len =3D iotlb->addr_mask + 1; > - bool writable =3D 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. > - */ > - mr =3D address_space_translate(&address_space_memory, > - iotlb->translated_addr, > - &xlat, &len, writable, > - MEMTXATTRS_UNSPECIFIED); > - if (!memory_region_is_ram(mr)) { > - error_report("iommu map to non memory area %"HWADDR_PRIx"", > - xlat); > - return false; > - } else if (memory_region_has_ram_discard_manager(mr)) { > - RamDiscardManager *rdm =3D memory_region_get_ram_discard_manager= (mr); > - MemoryRegionSection tmp =3D { > - .mr =3D mr, > - .offset_within_region =3D xlat, > - .size =3D int128_make64(len), > - }; > - > - /* > - * Malicious VMs can map memory into the IOMMU, which is expected > - * to remain discarded. vfio will pin all pages, populating memo= ry. > - * Disallow that. vmstate priorities make sure any RamDiscardMan= ager > - * were already restored before IOMMUs are restored. > - */ > - if (!ram_discard_manager_is_populated(rdm, &tmp)) { > - error_report("iommu map to discarded memory (e.g., unplugged= via" > - " virtio-mem): %"HWADDR_PRIx"", > - iotlb->translated_addr); > - return false; > - } > - > + if (mr_has_discard_manager) { > /* > - * Malicious VMs might trigger discarding of IOMMU-mapped memory= . The > - * pages will remain pinned inside vfio until unmapped, resultin= g in a > - * higher memory consumption than expected. If memory would get > - * populated again later, there would be an inconsistency betwee= n pages > - * pinned by vfio and pages seen by QEMU. This is the case until > - * unmapped from the IOMMU (e.g., during device reset). > + * Malicious VMs might trigger discarding of IOMMU-mapped memory. > + * The pages will remain pinned inside vfio until unmapped, > + * resulting in a higher memory consumption than expected. If me= mory > + * would get populated again later, there would be an inconsiste= ncy > + * between pages pinned by vfio and pages seen by QEMU. This is = the > + * case until unmapped from the IOMMU (e.g., during device reset= ). > * > - * With malicious guests, we really only care about pinning more= memory > - * than expected. RLIMIT_MEMLOCK set for the user/process can ne= ver be > - * exceeded and can be used to mitigate this problem. > + * With malicious guests, we really only care about pinning more > + * memory than expected. RLIMIT_MEMLOCK set for the user/process= can > + * never be exceeded and can be used to mitigate this problem. > */ > warn_report_once("Using vfio with vIOMMUs and coordinated discar= ding of" > " RAM (e.g., virtio-mem) works, however, malici= ous" > @@ -635,31 +594,7 @@ static bool vfio_get_xlat_addr(IOMMUTLBEntry *iotlb,= void **vaddr, > " intended via an IOMMU. It's possible to mitig= ate " > " by setting/adjusting RLIMIT_MEMLOCK."); > } > - > - /* > - * 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; > - } > - > - if (vaddr) { > - *vaddr =3D memory_region_get_ram_ptr(mr) + xlat; > - } > - > - if (ram_addr) { > - *ram_addr =3D memory_region_get_ram_addr(mr) + xlat; > - } > - > - if (read_only) { > - *read_only =3D !writable || mr->readonly; > - } > - > - return true; > } > - > static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) > { > VFIOGuestIOMMU *giommu =3D container_of(n, VFIOGuestIOMMU, n); > @@ -681,10 +616,17 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n,= IOMMUTLBEntry *iotlb) > =20 > if ((iotlb->perm & IOMMU_RW) !=3D IOMMU_NONE) { > bool read_only; > + bool mr_has_discard_manager; > =20 > - if (!vfio_get_xlat_addr(iotlb, &vaddr, NULL, &read_only)) { > + if (!memory_get_xlat_addr(iotlb, &vaddr, NULL, &read_only, > + &mr_has_discard_manager)) { > goto out; > } > + /* > + * if the mr has the discard_manager and the return value of > + * memory_get_xlat_addr() is ture then we need to warn > + */ > + vfio_mr_discard_manager_warn(mr_has_discard_manager); The wrapper should be around the memory_get_xlat_addr() function, not a separate helper whose only purpose is to trigger the error report, ie. extract all but the warn_report_once() into a shared function, keep vfio_get_xlat_addr(). The vfio call sites should not change. Thanks, Alex > /* > * vaddr is only valid until rcu_read_unlock(). But after > * vfio_dma_map has set up the mapping the pages will be > @@ -1349,6 +1291,7 @@ static void vfio_iommu_map_dirty_notify(IOMMUNotifi= er *n, IOMMUTLBEntry *iotlb) > VFIOContainer *container =3D giommu->container; > hwaddr iova =3D iotlb->iova + giommu->iommu_offset; > ram_addr_t translated_addr; > + bool mr_has_discard_manager; > =20 > trace_vfio_iommu_map_dirty_notify(iova, iova + iotlb->addr_mask); > =20 > @@ -1359,9 +1302,9 @@ static void vfio_iommu_map_dirty_notify(IOMMUNotifi= er *n, IOMMUTLBEntry *iotlb) > } > =20 > rcu_read_lock(); > - if (vfio_get_xlat_addr(iotlb, NULL, &translated_addr, NULL)) { > + if (memory_get_xlat_addr(iotlb, NULL, &translated_addr, NULL, > + &mr_has_discard_manager)) { > int ret; > - > ret =3D vfio_get_dirty_bitmap(container, iova, iotlb->addr_mask = + 1, > translated_addr); > if (ret) { > @@ -1370,6 +1313,12 @@ static void vfio_iommu_map_dirty_notify(IOMMUNotif= ier *n, IOMMUTLBEntry *iotlb) > container, iova, > iotlb->addr_mask + 1, ret); > } > + > + /* > + * if the mr has the discard_manager and the return value of > + * memory_get_xlat_addr() is ture then we need to warn > + */ > + vfio_mr_discard_manager_warn(mr_has_discard_manager); > } > rcu_read_unlock(); > } > diff --git a/include/exec/memory.h b/include/exec/memory.h > index bfb1de8eea..d1e79c39dc 100644 > --- a/include/exec/memory.h > +++ b/include/exec/memory.h > @@ -713,6 +713,10 @@ void ram_discard_manager_register_listener(RamDiscar= dManager *rdm, > void ram_discard_manager_unregister_listener(RamDiscardManager *rdm, > RamDiscardListener *rdl); > =20 > +bool memory_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr, > + ram_addr_t *ram_addr, bool *read_only, > + bool *mr_has_discard_manager); > + > typedef struct CoalescedMemoryRange CoalescedMemoryRange; > typedef struct MemoryRegionIoeventfd MemoryRegionIoeventfd; > =20 > diff --git a/softmmu/memory.c b/softmmu/memory.c > index 7ba2048836..bc0be3f62c 100644 > --- a/softmmu/memory.c > +++ b/softmmu/memory.c > @@ -33,6 +33,7 @@ > #include "qemu/accel.h" > #include "hw/boards.h" > #include "migration/vmstate.h" > +#include "exec/address-spaces.h" > =20 > //#define DEBUG_UNASSIGNED > =20 > @@ -2121,6 +2122,77 @@ void ram_discard_manager_unregister_listener(RamDi= scardManager *rdm, > rdmc->unregister_listener(rdm, rdl); > } > =20 > +/* Called with rcu_read_lock held. */ > +bool memory_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr, > + ram_addr_t *ram_addr, bool *read_only, > + bool *mr_has_discard_manager) > +{ > + MemoryRegion *mr; > + hwaddr xlat; > + hwaddr len =3D iotlb->addr_mask + 1; > + bool writable =3D iotlb->perm & IOMMU_WO; > + > + if (mr_has_discard_manager) { > + *mr_has_discard_manager =3D false; > + } > + /* > + * 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. > + */ > + mr =3D address_space_translate(&address_space_memory, iotlb->transla= ted_addr, > + &xlat, &len, writable, MEMTXATTRS_UNSPE= CIFIED); > + if (!memory_region_is_ram(mr)) { > + error_report("iommu map to non memory area %" HWADDR_PRIx "", xl= at); > + return false; > + } else if (memory_region_has_ram_discard_manager(mr)) { > + RamDiscardManager *rdm =3D memory_region_get_ram_discard_manager= (mr); > + MemoryRegionSection tmp =3D { > + .mr =3D mr, > + .offset_within_region =3D xlat, > + .size =3D int128_make64(len), > + }; > + if (mr_has_discard_manager) { > + *mr_has_discard_manager =3D true; > + } > + /* > + * Malicious VMs can map memory into the IOMMU, which is expected > + * to remain discarded. vfio will pin all pages, populating memo= ry. > + * Disallow that. vmstate priorities make sure any RamDiscardMan= ager > + * were already restored before IOMMUs are restored. > + */ > + if (!ram_discard_manager_is_populated(rdm, &tmp)) { > + error_report("iommu map to discarded memory (e.g., unplugged= via" > + " virtio-mem): %" HWADDR_PRIx "", > + iotlb->translated_addr); > + 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; > + } > + > + if (vaddr) { > + *vaddr =3D memory_region_get_ram_ptr(mr) + xlat; > + } > + > + if (ram_addr) { > + *ram_addr =3D memory_region_get_ram_addr(mr) + xlat; > + } > + > + if (read_only) { > + *read_only =3D !writable || mr->readonly; > + } > + > + return true; > +} > + > void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client) > { > uint8_t mask =3D 1 << client;