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=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 E70C1C433E0 for ; Tue, 30 Jun 2020 09:25:02 +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 B0AAE204EC for ; Tue, 30 Jun 2020 09:25:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FiTfk/QD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B0AAE204EC 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]:46562 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jqCVh-0004P5-Sy for qemu-devel@archiver.kernel.org; Tue, 30 Jun 2020 05:25:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45392) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqCUa-0002hE-Aa for qemu-devel@nongnu.org; Tue, 30 Jun 2020 05:23:52 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:41944 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jqCUY-00063p-Ba for qemu-devel@nongnu.org; Tue, 30 Jun 2020 05:23:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593509029; 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=9m1hmzt5chzlQr+t+Z2BWaepuHgAzCHaf17YlHMbZOY=; b=FiTfk/QDNz7Izi1uqo3GiBZyFf4gCbdP6j7Hzf1D/Z7wG7+zi0ABh2t08CQRpL8oQrPgPH 0RDVKCl22yHpM5BiDgkxOYJ2+wZjcWx9ysnCPmb3Ugwp95+xxZkh7W1dH6K9Ulz81ovuWD eJP+JkZez2koMCToPveqyeQxuzLfVpg= 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-311-hDuehoYEO_WKTB3FST4WZg-1; Tue, 30 Jun 2020 05:23:47 -0400 X-MC-Unique: hDuehoYEO_WKTB3FST4WZg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A1682107ACCA; Tue, 30 Jun 2020 09:23:46 +0000 (UTC) Received: from [10.72.13.159] (ovpn-13-159.pek2.redhat.com [10.72.13.159]) by smtp.corp.redhat.com (Postfix) with ESMTP id 68E317BED5; Tue, 30 Jun 2020 09:23:33 +0000 (UTC) Subject: Re: [RFC v2 1/1] memory: Delete assertion in memory_region_unregister_iommu_notifier To: "Michael S. Tsirkin" References: <20200626064122.9252-1-eperezma@redhat.com> <20200626064122.9252-2-eperezma@redhat.com> <20200626212917.GD175520@xz-x1> <8cf25190-53e6-8cbb-372b-e3d4ec714dc5@redhat.com> <20200628144746.GA239443@xz-x1> <54d2cdfd-97b8-9e1d-a607-d7a5e96be3a1@redhat.com> <20200629133403.GA266532@xz-x1> <2589d0e9-cc5b-a4df-8790-189b49f1a40e@redhat.com> <1b4eaaaf-c2ab-0da8-afb4-1b7b4221e6cf@redhat.com> <20200630052148-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <49f547e1-dd87-7abe-1075-9dcece75b641@redhat.com> Date: Tue, 30 Jun 2020 17:23:31 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200630052148-mutt-send-email-mst@kernel.org> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.120; envelope-from=jasowang@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/30 00:34:33 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: Peter Maydell , Yan Zhao , Juan Quintela , qemu-devel@nongnu.org, Peter Xu , =?UTF-8?Q?Eugenio_P=c3=a9rez?= , Eric Auger , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/6/30 下午5:21, Michael S. Tsirkin wrote: > On Tue, Jun 30, 2020 at 04:29:19PM +0800, Jason Wang wrote: >> On 2020/6/30 上午10:41, Jason Wang wrote: >>> On 2020/6/29 下午9:34, Peter Xu wrote: >>>> On Mon, Jun 29, 2020 at 01:51:47PM +0800, Jason Wang wrote: >>>>> On 2020/6/28 下午10:47, Peter Xu wrote: >>>>>> On Sun, Jun 28, 2020 at 03:03:41PM +0800, Jason Wang wrote: >>>>>>> On 2020/6/27 上午5:29, Peter Xu wrote: >>>>>>>> Hi, Eugenio, >>>>>>>> >>>>>>>> (CCing Eric, Yan and Michael too) >>>>>>>> >>>>>>>> On Fri, Jun 26, 2020 at 08:41:22AM +0200, Eugenio Pérez wrote: >>>>>>>>> diff --git a/memory.c b/memory.c >>>>>>>>> index 2f15a4b250..7f789710d2 100644 >>>>>>>>> --- a/memory.c >>>>>>>>> +++ b/memory.c >>>>>>>>> @@ -1915,8 +1915,6 @@ void >>>>>>>>> memory_region_notify_one(IOMMUNotifier >>>>>>>>> *notifier, >>>>>>>>>             return; >>>>>>>>>         } >>>>>>>>> -    assert(entry->iova >= notifier->start && >>>>>>>>> entry_end <= notifier->end); >>>>>>>> I can understand removing the assertion should solve >>>>>>>> the issue, however imho >>>>>>>> the major issue is not about this single assertion >>>>>>>> but the whole addr_mask >>>>>>>> issue behind with virtio... >>>>>>> I don't get here, it looks to the the range was from >>>>>>> guest IOMMU drivers. >>>>>> Yes.  Note that I didn't mean that it's a problem in virtio, >>>>>> it's just the fact >>>>>> that virtio is the only one I know that would like to >>>>>> support arbitrary address >>>>>> range for the translated region.  I don't know about tcg, >>>>>> but vfio should still >>>>>> need some kind of page alignment in both the address and the >>>>>> addr_mask.  We >>>>>> have that assumption too across the memory core when we do >>>>>> translations. >>>>> Right but it looks to me the issue is not the alignment. >>>>> >>>>> >>>>>> A further cause of the issue is the MSI region when vIOMMU >>>>>> enabled - currently >>>>>> we implemented the interrupt region using another memory >>>>>> region so it split the >>>>>> whole DMA region into two parts.  That's really a clean approach to IR >>>>>> implementation, however that's also a burden to the >>>>>> invalidation part because >>>>>> then we'll need to handle things like this when the listened >>>>>> range is not page >>>>>> alighed at all (neither 0-0xfedffff, nor 0xfef0000-MAX).  If >>>>>> without the IR >>>>>> region (so the whole iommu address range will be a single FlatRange), >>>>> Is this a bug? I remember that at least for vtd, it won't do any >>>>> DMAR on the >>>>> intrrupt address range >>>> I don't think it's a bug, at least it's working as how I >>>> understand...  that >>>> interrupt range is using an IR region, that's why I said the IR >>>> region splits >>>> the DMAR region into two pieces, so we have two FlatRange for the same >>>> IOMMUMemoryRegion. >>> >>> I don't check the qemu code but if "a single FlatRange" means >>> 0xFEEx_xxxx is subject to DMA remapping, OS need to setup passthrough >>> mapping for that range in order to get MSI to work. This is not what vtd >>> spec said: >>> >>> """ >>> >>> 3.14 Handling Requests to Interrupt Address Range >>> >>> Requests without PASID to address range 0xFEEx_xxxx are treated as >>> potential interrupt requests and are not subjected to DMA remapping >>> (even if translation structures specify a mapping for this >>> range). Instead, remapping hardware can be enabled to subject such >>> interrupt requests to interrupt remapping. >>> >>> """ >>> >>> My understanding is vtd won't do any DMA translation on 0xFEEx_xxxx even >>> if IR is not enabled. >> >> Ok, we had a dedicated mr for interrupt: >> >> memory_region_add_subregion_overlap(MEMORY_REGION(&vtd_dev_as->iommu), >> VTD_INTERRUPT_ADDR_FIRST, >> &vtd_dev_as->iommu_ir, 1); >> >> So it should be fine. I guess the reason that I'm asking is that I thought >> "IR" means "Interrupt remapping" but in fact it means "Interrupt Region"? >> >> But I'm still not clear about the invalidation part for interrupt region, >> maybe you can elaborate a little more on this. >> >> Btw, I think guest can trigger the assert in vtd_do_iommu_translate() if we >> teach vhost to DMA to that region: > > Why would we want to? I meant a buggy(malicious) guest driver. Thanks > >>     /* >>      * We have standalone memory region for interrupt addresses, we >>      * should never receive translation requests in this region. >>      */ >>     assert(!vtd_is_interrupt_addr(addr)); >> >> Is this better to return false here? (We can work on the fix for vhost but >> it should be not trivial) >> >> Thanks >>