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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 A8F0BC0044D for ; Sat, 14 Mar 2020 18:23:25 +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 7180420751 for ; Sat, 14 Mar 2020 18:23:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Xp+cgMDc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7180420751 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]:47238 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jDBRU-0000Gd-E7 for qemu-devel@archiver.kernel.org; Sat, 14 Mar 2020 14:23:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38233) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jDBQr-00088I-65 for qemu-devel@nongnu.org; Sat, 14 Mar 2020 14:22:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jDBQp-00016y-8J for qemu-devel@nongnu.org; Sat, 14 Mar 2020 14:22:45 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:27703 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jDBQp-00012r-4r for qemu-devel@nongnu.org; Sat, 14 Mar 2020 14:22:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584210162; 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=IQb+iBTnzwuymekHVpiE0GaqWaAtgh1LKmDD/jRfaRE=; b=Xp+cgMDcEuQEqXMVQFsj+rdSIcmkc0Fj3Hpnv5BjD2HpO3mwUoPE+evXf16yG27BNj7f0k vvngN7OHt+Bqf57KElgTbGG5/7LAUPgHM/TWsh2vUEnQmdRG3Etfdg2DLN0y7fqu00q9UI JSHMnRuND7sglDxzteDtVmNArkuLsR8= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-401-CKnhZH5cNIuWvLSOmSkIbA-1; Sat, 14 Mar 2020 14:22:40 -0400 X-MC-Unique: CKnhZH5cNIuWvLSOmSkIbA-1 Received: by mail-wr1-f71.google.com with SMTP id u18so6211495wrn.11 for ; Sat, 14 Mar 2020 11:22:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=nvX4hyRK+FdnahxsvXMFwjI5fSn9UQUuLFLcGpb+YCs=; b=gou5pVFY7NkAgm10Ysz1lYpCmKndnXuSd4k4uC62pTUXpic2RidJjqzrPdbFBEYKEP 59vbW4SSl+DZy6sMJLRduhXiINbgEgImzSPW+YcXuBr3Uw1Md9JeHtHTyRt3z0IgNLOH YbNUmts+YlbFmo8skxvkjVWt1DiAcI1gIQBeWrZn1zzVR9luDul/EewAI8IjZ9DPpgTY ovmPzOzIu1e8e5gobNMUsNxff3z5magf0P+YqQINnKWEnfbdEQvHpjWP3y/9wkVfebDI DVx3ZNdBl5+SG+FYrCbfGqoLguAi/wHeZQSDkHMo609wxYzpKmhu1YBCOUxUdqukWsA2 cFlQ== X-Gm-Message-State: ANhLgQ3GyfOIU7eO/6h2rysYTscoVHompY9e6FaZVf3Ctz+RBT9eewD0 yfzLUywrdfRhFXSYkTAhgUfz8xRlR/1A7ZIiw31OSfQCww+VkRWul2JAbk5aq30QGezR4yWkw3B mf66AP0wLv6rSUbE= X-Received: by 2002:adf:f583:: with SMTP id f3mr6714649wro.243.1584210159505; Sat, 14 Mar 2020 11:22:39 -0700 (PDT) X-Google-Smtp-Source: ADFU+vvVREQqP5FW/+StaM0Ice/ouR7BrgiEMgy6Njnq+MZGD8V1g0t7DF5o0X//NdIQQkuxb9sqMQ== X-Received: by 2002:adf:f583:: with SMTP id f3mr6714632wro.243.1584210159250; Sat, 14 Mar 2020 11:22:39 -0700 (PDT) Received: from redhat.com (bzq-79-180-7-202.red.bezeqint.net. [79.180.7.202]) by smtp.gmail.com with ESMTPSA id o3sm23896329wme.36.2020.03.14.11.22.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 14 Mar 2020 11:22:38 -0700 (PDT) Date: Sat, 14 Mar 2020 14:22:36 -0400 From: "Michael S. Tsirkin" To: Brijesh Singh Subject: Re: [PATCH V2] vhost: correctly turn on VIRTIO_F_IOMMU_PLATFORM Message-ID: <20200314142114-mutt-send-email-mst@kernel.org> References: <20200226094357.25061-1-jasowang@redhat.com> <20200226142839.4263de9b.pasic@linux.ibm.com> <20200226083654-mutt-send-email-mst@kernel.org> <20200226163618.31aa86ed.pasic@linux.ibm.com> <20200226115009-mutt-send-email-mst@kernel.org> <20200227140215.2d12149c.pasic@linux.ibm.com> <20200227104233-mutt-send-email-mst@kernel.org> <20200313134446.782c5f7c.pasic@linux.ibm.com> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: Halil Pasic , Tom Lendacky , Jason Wang , qemu-devel@nongnu.org, qemu-stable@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Mar 13, 2020 at 03:27:59PM -0500, Brijesh Singh wrote: >=20 > On 3/13/20 7:44 AM, Halil Pasic wrote: > > [..] > >>> CCing Tom. @Tom does vhost-vsock work for you with SEV and current qe= mu? > >>> > >>> Also, one can specify iommu_platform=3Don on a device that ain't a pa= rt of > >>> a secure-capable VM, just for the fun of it. And that breaks > >>> vhost-vsock. Or is setting iommu_platform=3Don only valid if > >>> qemu-system-s390x is protected virtualization capable? > >>> > >>> BTW, I don't have a strong opinion on the fixes tag. We currently do = not > >>> recommend setting iommu_platform, and thus I don't think we care too > >>> much about past qemus having problems with it. > >>> > >>> Regards, > >>> Halil > >> > >> Let's just say if we do have a Fixes: tag we want to set it correctly = to > >> the commit that needs this fix. > >> > > I finally did some digging regarding the performance degradation. For > > s390x the performance degradation on vhost-net was introduced by commit > > 076a93d797 ("exec: simplify address_space_get_iotlb_entry"). Before > > IOMMUTLBEntry.addr_mask used to be based on plen, which in turn was > > calculated as the rest of the memory regions size (from address), and > > covered most of the guest address space. That is we didn't have a whole > > lot of IOTLB API overhead. > > > > With commit 076a93d797 I see IOMMUTLBEntry.addr_mask =3D=3D 0xfff which= comes > > as ~TARGET_PAGE_MASK from flatview_do_translate(). To have things worki= ng > > properly I applied 75e5b70e6, b021d1c044, and d542800d1e on the level o= f > > 076a93d797 and 076a93d797~1. > > > > Regarding vhost-vsock. It does not work with iommu_platform=3Don since = the > > very beginning (i.e. 8607f5c307 ("virtio: convert to use DMA api")). No= t > > sure if that is a good or a bad thing. (If the vhost driver in the kern= el > > would actually have to do the IOTLB translation, then failing in case > > where it does not support it seems sane. The problem is that > > ACCESS_PLATFORM is used for more than one thing (needs translation, and > > restricted memory access).) > > > > I don't think I've heard back from AMD whether vsock works with SEV or > > not... I don't have access to HW to test it myself. >=20 >=20 > I just tried vhost-vsock on AMD SEV machine and it does not work. I am > using FC31 (qemu 4.1.1.1.fc31). Neither does vhost scsi - no ACCESS_PLATFORM support. But with Jason's patch I think both should work. Pls give it a try. >=20 > > We (s390) don't require this being backported to the stable qemus, > > because for us iommu_platform=3Don becomes relevant with protected > > virtualization, and those qemu versions don't support it. > > > > Cheers, > > Halil > >