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,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 4C8ABC433E0 for ; Wed, 13 Jan 2021 23:58:25 +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 98D9D21734 for ; Wed, 13 Jan 2021 23:58:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 98D9D21734 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]:53246 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kzq1u-0006fd-Tc for qemu-devel@archiver.kernel.org; Wed, 13 Jan 2021 18:58:22 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:36096) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kzq15-0006FD-Cj for qemu-devel@nongnu.org; Wed, 13 Jan 2021 18:57:31 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:54954) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kzq12-0006Hs-K8 for qemu-devel@nongnu.org; Wed, 13 Jan 2021 18:57:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610582246; 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=9DrykCmrESMmR9d57sCtm7+qDAaTPupQvQuxNP8hESU=; b=WSVQEuzlbLoCjYIyecA7yplWTgahvQdWfGWd26ZYJwvcSo9YBbeKnvINQAOL0kK0WINZfm FFxR/HkKqHLyh4rHnPbVqCJDH24BFiie5tSI4fIynDFUvpt6x73+K8HcCpO2Y9C77JOzLq x3WGNGrQ8KTb+QW+xRhb+8kszSnQAZQ= 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-584-nAgt4nSVNimekTgVuK59xg-1; Wed, 13 Jan 2021 18:57:24 -0500 X-MC-Unique: nAgt4nSVNimekTgVuK59xg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 272FD801FD4; Wed, 13 Jan 2021 23:57:23 +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 1A8086A8F2; Wed, 13 Jan 2021 23:57:09 +0000 (UTC) Date: Wed, 13 Jan 2021 16:57:08 -0700 From: Alex Williamson To: David Hildenbrand Subject: Re: [PATCH v4 11/11] vfio: Disable only uncoordinated discards Message-ID: <20210113165708.45a8701c@omen.home.shazbot.org> In-Reply-To: <20210107133423.44964-12-david@redhat.com> References: <20210107133423.44964-1-david@redhat.com> <20210107133423.44964-12-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.25, 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: Marek Kedzierski , Pankaj Gupta , Wei Yang , "Michael S. Tsirkin" , qemu-devel@nongnu.org, Peter Xu , "Dr . David Alan Gilbert" , Auger Eric , Pankaj Gupta , teawater , Jonathan Cameron , Paolo Bonzini , Igor Mammedov Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 7 Jan 2021 14:34:23 +0100 David Hildenbrand wrote: > We support coordinated discarding of RAM using the RamDiscardMgr. Let's > unlock support for coordinated discards, keeping uncoordinated discards > (e.g., via virtio-balloon) disabled. > > This unlocks virtio-mem + vfio. Note that vfio used via "nvme://" by the > block layer has to be implemented/unlocked separately. For now, > virtio-mem only supports x86-64 - spapr IOMMUs are not tested/affected. I think SPAPR always uses a vIOMMU, but I won't claim to understand it. Is there anything other than testing that restricts it to x86-64? ARM and S390 will use the same type1 IOMMU backend as far as vfio support is concerned. Should we do something more than put it in a commit log if we really want to prevent it elsewhere? Thanks, Alex > 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). > > Reviewed-by: Pankaj Gupta > 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 | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/hw/vfio/common.c b/hw/vfio/common.c > index 2b9ba3f8c9..ee7a82524a 100644 > --- a/hw/vfio/common.c > +++ b/hw/vfio/common.c > @@ -1976,8 +1976,10 @@ 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. > */ > - ret = ram_block_discard_disable(true); > + ret = ram_block_uncoordinated_discard_disable(true); > if (ret) { > error_setg_errno(errp, -ret, "Cannot set discarding of RAM broken"); > return ret; > @@ -2157,7 +2159,7 @@ close_fd_exit: > close(fd); > > put_space_exit: > - ram_block_discard_disable(false); > + ram_block_uncoordinated_discard_disable(false); > vfio_put_address_space(space); > > return ret; > @@ -2279,7 +2281,7 @@ void vfio_put_group(VFIOGroup *group) > } > > if (!group->ram_block_discard_allowed) { > - ram_block_discard_disable(false); > + ram_block_uncoordinated_discard_disable(false); > } > vfio_kvm_device_del_group(group); > vfio_disconnect_container(group); > @@ -2333,7 +2335,7 @@ 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); > + ram_block_uncoordinated_discard_disable(false); > } > } >