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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 00E2EC0218F for ; Thu, 30 Jan 2025 16:42:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tdXc8-00061W-GC; Thu, 30 Jan 2025 11:42:00 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdXc3-0005xU-SV for qemu-devel@nongnu.org; Thu, 30 Jan 2025 11:41:56 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdXc1-0005Xs-I2 for qemu-devel@nongnu.org; Thu, 30 Jan 2025 11:41:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1738255310; h=from:from:reply-to: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=3arpfGjz6zW/uQSYzu6lLVfacbd5PeZ0F2jl58xZJ9I=; b=XiB85PDsJ78cfQ70Ai6pBH0pjL+5W5LINUPYFoNcD2gl5PfF4GecxTcza5TqWcmJv0gHrg SwyEHhfD9A7hFda9UBBXezYHsFK4wAKNloWFww3tuK+XzADU3nTznt6BxEbMoyW7JNDJv9 eaVjhfHyKs2WudsSW0P1XxvpkPqD/+w= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-512-s5c8dsQbO0KASBhwAG12-g-1; Thu, 30 Jan 2025 11:41:47 -0500 X-MC-Unique: s5c8dsQbO0KASBhwAG12-g-1 X-Mimecast-MFC-AGG-ID: s5c8dsQbO0KASBhwAG12-g Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4B2D01801F1F; Thu, 30 Jan 2025 16:41:45 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.184]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 35AAE18008D8; Thu, 30 Jan 2025 16:41:39 +0000 (UTC) Date: Thu, 30 Jan 2025 16:41:36 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Eric Auger Cc: Shameer Kolothum , qemu-arm@nongnu.org, qemu-devel@nongnu.org, peter.maydell@linaro.org, jgg@nvidia.com, nicolinc@nvidia.com, ddutile@redhat.com, linuxarm@huawei.com, wangzhou1@hisilicon.com, jiangkunkun@huawei.com, jonathan.cameron@huawei.com, zhangfei.gao@linaro.org, Andrea Bolognani Subject: Re: [RFC PATCH 0/5] hw/arm/virt: Add support for user-creatable nested SMMUv3 Message-ID: References: <20241108125242.60136-1-shameerali.kolothum.thodi@huawei.com> <8ce24003-66ad-43da-b68a-14686758a85a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8ce24003-66ad-43da-b68a-14686758a85a@redhat.com> User-Agent: Mutt/2.2.13 (2024-03-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.3, 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_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Nov 18, 2024 at 11:50:46AM +0100, Eric Auger wrote: > Hi Shameer, > > On 11/8/24 13:52, Shameer Kolothum wrote: > > Hi, > > > > This series adds initial support for a user-creatable "arm-smmuv3-nested" > > device to Qemu. At present the Qemu ARM SMMUv3 emulation is per machine > > and cannot support multiple SMMUv3s. > > > > In order to support vfio-pci dev assignment with vSMMUv3, the physical > > SMMUv3 has to be configured in nested mode. Having a pluggable > > "arm-smmuv3-nested" device enables us to have multiple vSMMUv3 for Guests > > running on a host with multiple physical SMMUv3s. A few benefits of doing > > this are, > > > > 1. Avoid invalidation broadcast or lookup in case devices are behind > >    multiple phys SMMUv3s. > > 2. Makes it easy to handle phys SMMUv3s that differ in features. > > 3. Easy to handle future requirements such as vCMDQ support. > > > > This is based on discussions/suggestions received for a previous RFC by > > Nicolin here[0]. > > > > This series includes, > >  -Adds support for "arm-smmuv3-nested" device. At present only virt is > >   supported and is using _plug_cb() callback to hook the sysbus mem > >   and irq (Not sure this has any negative repercussions). Patch #3. > >  -Provides a way to associate a pci-bus(pxb-pcie) to the above device. > >   Patch #3. > >  -The last patch is adding RMR support for MSI doorbell handling. Patch #5. > >   This may change in future[1]. > > > > This RFC is for initial discussion/test purposes only and includes patches > > that are only relevant for adding the "arm-smmuv3-nested" support. For the > > complete branch please find, > > https://github.com/hisilicon/qemu/tree/private-smmuv3-nested-dev-rfc-v1 > > > > Few ToDos to note, > > 1. At present default-bus-bypass-iommu=on should be set when > >    arm-smmuv3-nested dev is specified. Otherwise you may get an IORT > >    related boot error.  Requires fixing. > > 2. Hot adding a device is not working at the moment. Looks like pcihp irq issue. > >    Could be a bug in IORT id mappings. > > 3. The above branch doesn't support vSVA yet. > > > > Hopefully this is helpful in taking the discussion forward. Please take a > > look and let me know. > > > > How to use it(Eg:): > > > > On a HiSilicon platform that has multiple physical SMMUv3s, the ACC ZIP VF > > devices and HNS VF devices are behind different SMMUv3s. So for a Guest, > > specify two smmuv3-nested devices each behind a pxb-pcie as below, > > > > ./qemu-system-aarch64 -machine virt,gic-version=3,default-bus-bypass-iommu=on \ > > -enable-kvm -cpu host -m 4G -smp cpus=8,maxcpus=8 \ > > -object iommufd,id=iommufd0 \ > > -bios QEMU_EFI.fd \ > > -kernel Image \ > > -device virtio-blk-device,drive=fs \ > > -drive if=none,file=rootfs.qcow2,id=fs \ > > -device pxb-pcie,id=pcie.1,bus_nr=8,bus=pcie.0 \ > > -device pcie-root-port,id=pcie.port1,bus=pcie.1,chassis=1 \ > > -device arm-smmuv3-nested,id=smmuv1,pci-bus=pcie.1 \ > > -device vfio-pci,host=0000:7d:02.1,bus=pcie.port1,iommufd=iommufd0 \ > > -device pxb-pcie,id=pcie.2,bus_nr=16,bus=pcie.0 \ > > -device pcie-root-port,id=pcie.port2,bus=pcie.2,chassis=2 \ > > -device arm-smmuv3-nested,id=smmuv2,pci-bus=pcie.2 \ > > -device vfio-pci,host=0000:75:00.1,bus=pcie.port2,iommufd=iommufd0 \ > > -append "rdinit=init console=ttyAMA0 root=/dev/vda2 rw earlycon=pl011,0x9000000" \ > > -device virtio-9p-pci,fsdev=p9fs2,mount_tag=p9,bus=pcie.0 \ > > -fsdev local,id=p9fs2,path=p9root,security_model=mapped \ > This kind of instantiation matches what I had in mind. It is > questionable whether the legacy SMMU shouldn't be migrated to that mode > too (instead of using a machine option setting), depending on Peter's > feedbacks and also comments from Libvirt guys. Adding Andrea in the loop. Yeah, looking at the current config I'm pretty surprised to see it configured with '-machine virt,iommu=ssmuv3', where 'smmuv3' is a type name. This effectively a back-door reinvention of the '-device' arg. I think it'd make more sense to deprecate the 'iommu' property on the machine, and allow '-device ssmu3,pci-bus=pcie.0' to associate the IOMMU with the PCI root bus, so we have consistent approaches for all SMMU impls. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|