From nobody Mon Feb 9 16:18:55 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1625775373487472.304100278384; Thu, 8 Jul 2021 13:16:13 -0700 (PDT) Received: from localhost ([::1]:46988 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m1aRQ-0000OL-A7 for importer@patchew.org; Thu, 08 Jul 2021 16:16:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59240) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m1aA6-0007d1-4f for qemu-devel@nongnu.org; Thu, 08 Jul 2021 15:58:18 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:35505) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m1aA3-0002jS-NH for qemu-devel@nongnu.org; Thu, 08 Jul 2021 15:58:17 -0400 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-6-QXDYRVrhOb-kSrPCQFeMJg-1; Thu, 08 Jul 2021 15:58:13 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B73411937FC9; Thu, 8 Jul 2021 19:57:49 +0000 (UTC) Received: from localhost (unknown [10.22.8.123]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6E2CF60C13; Thu, 8 Jul 2021 19:57:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625774295; 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=v+oduKwky4JwZRsX/JwVarVY96A/4FN8qrmBVH0MMfQ=; b=Y4n0z+g5A+awfjtFthB/t5a6eujtUB1Y695x6FI5CacGryonjyrZX5+T5ZMF4H9hX5qmbS 1NkVYVYYlzgdl3OXFqUv9ERtTldD+t3P8FawM3aostsxvggs9z3gAQ60P/Uhs4KGARrl3w 4IM7Tq9banHD6/afJB95atLQg12Loh4= X-MC-Unique: QXDYRVrhOb-kSrPCQFeMJg-1 From: Eduardo Habkost To: Peter Maydell , qemu-devel@nongnu.org Subject: [PULL v2 15/15] vfio: Disable only uncoordinated discards for VFIO_TYPE1 iommus Date: Thu, 8 Jul 2021 15:55:52 -0400 Message-Id: <20210708195552.2730970-16-ehabkost@redhat.com> In-Reply-To: <20210708195552.2730970-1-ehabkost@redhat.com> References: <20210708195552.2730970-1-ehabkost@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ehabkost@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=ehabkost@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=-0.45, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Pankaj Gupta , Eduardo Habkost , "Michael S . Tsirkin" , David Hildenbrand , "Dr . David Alan Gilbert" , Peter Xu , Auger Eric , Alex Williamson , teawater , Igor Mammedov , Paolo Bonzini , Marek Kedzierski , Wei Yang Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1625775375111100001 Content-Type: text/plain; charset="utf-8" From: David Hildenbrand We support coordinated discarding of RAM using the RamDiscardManager for the VFIO_TYPE1 iommus. Let's unlock support for coordinated discards, keeping uncoordinated discards (e.g., via virtio-balloon) disabled if possible. This unlocks virtio-mem + vfio on x86-64. Note that vfio used via "nvme://" by the block layer has to be implemented/unlocked separately. For now, virtio-mem only supports x86-64; we don't restrict RamDiscardManager to x86-64, though: arm64 and s390x are supposed to work as well, and we'll test once unlocking virtio-mem support. The spapr IOMMUs will need special care, to be tackled later, e.g.., once supporting virtio-mem. Note: The block size of a virtio-mem device has to be set to sane sizes, depending on the maximum hotplug size - to not run out of vfio mappings. The default virtio-mem block size is usually in the range of a couple of MBs. The maximum number of mapping is 64k, shared with other users. Assume you want to hotplug 256GB using virtio-mem - the block size would have to be set to at least 8 MiB (resulting in 32768 separate mappings). Acked-by: Alex Williamson Reviewed-by: Alex Williamson Acked-by: Michael S. Tsirkin Cc: Paolo Bonzini Cc: "Michael S. Tsirkin" Cc: Alex Williamson Cc: Dr. David Alan Gilbert Cc: Igor Mammedov Cc: Pankaj Gupta Cc: Peter Xu Cc: Auger Eric Cc: Wei Yang Cc: teawater Cc: Marek Kedzierski Signed-off-by: David Hildenbrand Message-Id: <20210413095531.25603-14-david@redhat.com> Signed-off-by: Eduardo Habkost --- hw/vfio/common.c | 65 +++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 53 insertions(+), 12 deletions(-) diff --git a/hw/vfio/common.c b/hw/vfio/common.c index 8a9bbf27918..3f0d1113608 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -135,6 +135,29 @@ static const char *index_to_str(VFIODevice *vbasedev, = int index) } } =20 +static int vfio_ram_block_discard_disable(VFIOContainer *container, bool s= tate) +{ + switch (container->iommu_type) { + case VFIO_TYPE1v2_IOMMU: + case VFIO_TYPE1_IOMMU: + /* + * We support coordinated discarding of RAM via the RamDiscardMana= ger. + */ + return ram_block_uncoordinated_discard_disable(state); + default: + /* + * VFIO_SPAPR_TCE_IOMMU most probably works just fine with + * RamDiscardManager, however, it is completely untested. + * + * VFIO_SPAPR_TCE_v2_IOMMU with "DMA memory preregistering" does + * completely the opposite of managing mapping/pinning dynamically= as + * required by RamDiscardManager. We would have to special-case se= ctions + * with a RamDiscardManager. + */ + return ram_block_discard_disable(state); + } +} + int vfio_set_irq_signaling(VFIODevice *vbasedev, int index, int subindex, int action, int fd, Error **errp) { @@ -1977,15 +2000,25 @@ static int vfio_connect_container(VFIOGroup *group,= AddressSpace *as, * new memory, it will not yet set ram_block_discard_set_required() and * therefore, neither stops us here or deals with the sudden memory * consumption of inflated memory. + * + * We do support discarding of memory coordinated via the RamDiscardMa= nager + * with some IOMMU types. vfio_ram_block_discard_disable() handles the + * details once we know which type of IOMMU we are using. */ - ret =3D ram_block_discard_disable(true); - if (ret) { - error_setg_errno(errp, -ret, "Cannot set discarding of RAM broken"= ); - return ret; - } =20 QLIST_FOREACH(container, &space->containers, next) { if (!ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &container->fd)) { + ret =3D vfio_ram_block_discard_disable(container, true); + if (ret) { + error_setg_errno(errp, -ret, + "Cannot set discarding of RAM broken"); + if (ioctl(group->fd, VFIO_GROUP_UNSET_CONTAINER, + &container->fd)) { + error_report("vfio: error disconnecting group %d from" + " container", group->groupid); + } + return ret; + } group->container =3D container; QLIST_INSERT_HEAD(&container->group_list, group, container_nex= t); vfio_kvm_device_add_group(group); @@ -2023,6 +2056,12 @@ static int vfio_connect_container(VFIOGroup *group, = AddressSpace *as, goto free_container_exit; } =20 + ret =3D vfio_ram_block_discard_disable(container, true); + if (ret) { + error_setg_errno(errp, -ret, "Cannot set discarding of RAM broken"= ); + goto free_container_exit; + } + switch (container->iommu_type) { case VFIO_TYPE1v2_IOMMU: case VFIO_TYPE1_IOMMU: @@ -2070,7 +2109,7 @@ static int vfio_connect_container(VFIOGroup *group, A= ddressSpace *as, if (ret) { error_setg_errno(errp, errno, "failed to enable container"= ); ret =3D -errno; - goto free_container_exit; + goto enable_discards_exit; } } else { container->prereg_listener =3D vfio_prereg_listener; @@ -2082,7 +2121,7 @@ static int vfio_connect_container(VFIOGroup *group, A= ddressSpace *as, ret =3D -1; error_propagate_prepend(errp, container->error, "RAM memory listener initialization failed: "); - goto free_container_exit; + goto enable_discards_exit; } } =20 @@ -2095,7 +2134,7 @@ static int vfio_connect_container(VFIOGroup *group, A= ddressSpace *as, if (v2) { memory_listener_unregister(&container->prereg_listener); } - goto free_container_exit; + goto enable_discards_exit; } =20 if (v2) { @@ -2110,7 +2149,7 @@ static int vfio_connect_container(VFIOGroup *group, A= ddressSpace *as, if (ret) { error_setg_errno(errp, -ret, "failed to remove existing window"); - goto free_container_exit; + goto enable_discards_exit; } } else { /* The default table uses 4K pages */ @@ -2151,6 +2190,9 @@ listener_release_exit: vfio_kvm_device_del_group(group); vfio_listener_release(container); =20 +enable_discards_exit: + vfio_ram_block_discard_disable(container, false); + free_container_exit: g_free(container); =20 @@ -2158,7 +2200,6 @@ close_fd_exit: close(fd); =20 put_space_exit: - ram_block_discard_disable(false); vfio_put_address_space(space); =20 return ret; @@ -2280,7 +2321,7 @@ void vfio_put_group(VFIOGroup *group) } =20 if (!group->ram_block_discard_allowed) { - ram_block_discard_disable(false); + vfio_ram_block_discard_disable(group->container, false); } vfio_kvm_device_del_group(group); vfio_disconnect_container(group); @@ -2334,7 +2375,7 @@ int vfio_get_device(VFIOGroup *group, const char *nam= e, =20 if (!group->ram_block_discard_allowed) { group->ram_block_discard_allowed =3D true; - ram_block_discard_disable(false); + vfio_ram_block_discard_disable(group->container, false); } } =20 --=20 2.31.1