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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 B9231C433E0 for ; Tue, 16 Feb 2021 19:05:12 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 438DA64D99 for ; Tue, 16 Feb 2021 19:05:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 438DA64D99 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56918 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lC5ep-0007SS-63 for qemu-devel@archiver.kernel.org; Tue, 16 Feb 2021 14:05:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:43820) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lC5dR-00065D-Gt for qemu-devel@nongnu.org; Tue, 16 Feb 2021 14:03:45 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:57058) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lC5dN-0003VB-0b for qemu-devel@nongnu.org; Tue, 16 Feb 2021 14:03:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613502219; 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=UTFCsvcvtfMAcrB0zAVnL6dXjEKnyh9IplKodkX2Dz0=; b=Nnl2O7j8fKTCLB9gsWidBhTFjTeNvZqrUoCUgxxPFcEEbH3/h8Zd8Vrr8tzq5ufn/heOlj eQKtxL+ZS0QP605npG1B0ykGSj82hjUsbhE6baWNfiaV45qp824LQ/1zEIw4AhkB9UevG2 Ron0+lch4Cl99t4XkTZRGhFqXgqR5WM= 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-450-5tcsM58dOAWHTKqKIRZgZQ-1; Tue, 16 Feb 2021 14:03:35 -0500 X-MC-Unique: 5tcsM58dOAWHTKqKIRZgZQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E2FC6801979; Tue, 16 Feb 2021 19:03:33 +0000 (UTC) Received: from omen.home.shazbot.org (ovpn-112-255.phx2.redhat.com [10.3.112.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4B5B610023AB; Tue, 16 Feb 2021 19:03:20 +0000 (UTC) Date: Tue, 16 Feb 2021 12:03:19 -0700 From: Alex Williamson To: David Hildenbrand Subject: Re: [PATCH v5 11/11] vfio: Disable only uncoordinated discards for VFIO_TYPE1 iommus Message-ID: <20210216120319.435fdcd3@omen.home.shazbot.org> In-Reply-To: <20210121110540.33704-12-david@redhat.com> References: <20210121110540.33704-1-david@redhat.com> <20210121110540.33704-12-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=alex.williamson@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=alex.williamson@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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 , Wei Yang , "Michael S. Tsirkin" , Jonathan Cameron , qemu-devel@nongnu.org, Peter Xu , "Dr . David Alan Gilbert" , Auger Eric , teawater , Igor Mammedov , Paolo Bonzini , Marek Kedzierski Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 21 Jan 2021 12:05:40 +0100 David Hildenbrand wrote: > We support coordinated discarding of RAM using the RamDiscardMgr 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 RamDiscardMgr 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). > > 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 > --- > hw/vfio/common.c | 63 +++++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 51 insertions(+), 12 deletions(-) Acked-by: Alex Williamson Reviewed-by: Alex Williamson > > diff --git a/hw/vfio/common.c b/hw/vfio/common.c > index 15ecd05a4b..d879b8ab92 100644 > --- a/hw/vfio/common.c > +++ b/hw/vfio/common.c > @@ -135,6 +135,27 @@ static const char *index_to_str(VFIODevice *vbasedev, int index) > } > } > > +static int vfio_ram_block_discard_disable(VFIOContainer *container, bool state) > +{ > + switch (container->iommu_type) { > + case VFIO_TYPE1v2_IOMMU: > + case VFIO_TYPE1_IOMMU: > + /* We support coordinated discarding of RAM via the RamDiscardMgr. */ > + return ram_block_uncoordinated_discard_disable(state); > + default: > + /* > + * VFIO_SPAPR_TCE_IOMMU most probably works just fine with > + * RamDiscardMgr, 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 RamDiscardMgr. We would have to special-case sections > + * with a RamDiscardMgr. > + */ > + return ram_block_discard_disable(state); > + } > +} > + > int vfio_set_irq_signaling(VFIODevice *vbasedev, int index, int subindex, > int action, int fd, Error **errp) > { > @@ -1979,15 +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 RamDiscardMgr > + * with some IOMMU types. vfio_ram_block_discard_disable() handles the > + * details once we know which type of IOMMU we are using. > */ > - ret = ram_block_discard_disable(true); > - if (ret) { > - error_setg_errno(errp, -ret, "Cannot set discarding of RAM broken"); > - return ret; > - } > > QLIST_FOREACH(container, &space->containers, next) { > if (!ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &container->fd)) { > + ret = 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 = container; > QLIST_INSERT_HEAD(&container->group_list, group, container_next); > vfio_kvm_device_add_group(group); > @@ -2025,6 +2056,12 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as, > goto free_container_exit; > } > > + ret = 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: > @@ -2072,7 +2109,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as, > if (ret) { > error_setg_errno(errp, errno, "failed to enable container"); > ret = -errno; > - goto free_container_exit; > + goto enable_discards_exit; > } > } else { > container->prereg_listener = vfio_prereg_listener; > @@ -2084,7 +2121,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as, > ret = -1; > error_propagate_prepend(errp, container->error, > "RAM memory listener initialization failed: "); > - goto free_container_exit; > + goto enable_discards_exit; > } > } > > @@ -2097,7 +2134,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as, > if (v2) { > memory_listener_unregister(&container->prereg_listener); > } > - goto free_container_exit; > + goto enable_discards_exit; > } > > if (v2) { > @@ -2112,7 +2149,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *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 */ > @@ -2153,6 +2190,9 @@ listener_release_exit: > vfio_kvm_device_del_group(group); > vfio_listener_release(container); > > +enable_discards_exit: > + vfio_ram_block_discard_disable(container, false); > + > free_container_exit: > g_free(container); > > @@ -2160,7 +2200,6 @@ close_fd_exit: > close(fd); > > put_space_exit: > - ram_block_discard_disable(false); > vfio_put_address_space(space); > > return ret; > @@ -2282,7 +2321,7 @@ void vfio_put_group(VFIOGroup *group) > } > > 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); > @@ -2336,7 +2375,7 @@ int vfio_get_device(VFIOGroup *group, const char *name, > > if (!group->ram_block_discard_allowed) { > group->ram_block_discard_allowed = true; > - ram_block_discard_disable(false); > + vfio_ram_block_discard_disable(group->container, false); > } > } >