From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f41.google.com (mail-qv1-f41.google.com [209.85.219.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 809FA3546C8 for ; Wed, 2 Sep 2026 01:51:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788313907; cv=none; b=dCShzgSXjeNMBffnY9RxMW6aroSD6pn1+pFNAzsid1N2j5Ah2wWw7/icbfKo9QeYKAkJr/X+z4xMiftxC6ZCnSji4PGtLuz1peDyNhtzYjU27uTCBcTESgHUCgthLkHQ7llohRnr/UgqeFD4kqYzf/wJhFVFCFCQQOFV2Thcd98= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788313907; c=relaxed/simple; bh=E+oXMdrF2sleLVDXDyRpoFuZgDFkHIlL9VN1wy6t690=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PknIR0tO3CWOW+gDO2+aNyl5OnLlwHGBRljoD2iTnYf3n5LpcY4XTnLshF3AxEF+/UpV7ZompSvZPOW1ha/RFvf9nYOpsnfqOqbmJQKfPnG3lVCQZBMuELU/jZsYKpXWfQoB8BFGZa6OHG5V0IQq/rZuw9gd+3pXJCmRCpNWUdU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca; spf=pass smtp.mailfrom=ziepe.ca; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b=Cokh/1k8; arc=none smtp.client-ip=209.85.219.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="Cokh/1k8" Received: by mail-qv1-f41.google.com with SMTP id 6a1803df08f44-90e8535619bso5656686d6.2 for ; Tue, 01 Sep 2026 18:51:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1788313900; x=1788918700; darn=lists.linux.dev; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=E+oXMdrF2sleLVDXDyRpoFuZgDFkHIlL9VN1wy6t690=; b=Cokh/1k85vJ4CHgv5xK2B6hIC0TBeuhQwpiDPs/T6jzFx4j3tSi7FxhK/fuEvlQJpV PgJwRJPA29geLfVJFt9nIH/L/Ep+i9sendCwtO27hjtPQJe/Q9ddQRyIAPkwcfg4jZ5w lIMAtNsKQ26s64ofj9UIYqkeXP9QFuEtUoYpfxdijkLiZHG+VvmcTe9JmBvIdJbg91rh DSxOusKi5yjI2HL9XBTXqNEJRuHLGevNFEgCv+Hkk7NE0pXnvTwRxr8XJiL8pZCoICgp OxNZ7S3Kd5fjQITLcgeixgJEVstV/UKqf67D7/AOutS/eCV5TM5/kU1mIy9mJLBior2o xFAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788313900; x=1788918700; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=E+oXMdrF2sleLVDXDyRpoFuZgDFkHIlL9VN1wy6t690=; b=FVg4KkXlcBE1od9BQxouQS4F1Chwn4YZP+qj8Y1VqKs2/UmoRVj+vpRCcRbEKPazCJ f9n4uN2DHBLzpA9hinNzTS9TpnIeLsMNCm9+fnGbxypF3M3k87Z7rZdSzPQ6RcpNfT+z oNSRD1mVpJqd/9o4obUdpNFvU/TsYDjZFZDlhmygNCcXctExGyNVe/YlC+ZR0fE/pKVt k2OtKg84AkOTzv0rTshdueyBKmSmFTmnTojTmDAPbDkbWz6JYwhPCGM48g67ApcuSl2K urUYHrmZEs2tASjexlXE5SYfUii+L0OdEtody5GAe8rrQDo3x6DEiY2NlHA4Uw/xeXlD sfXw== X-Forwarded-Encrypted: i=1; AKwUvBzQ2xwAH09eW9ZhsiJMEVLrFf9kvPalAc064UEENws9ou1ac3rRR/N0JrOGk7hsA+QuKNNDBR8=@lists.linux.dev X-Gm-Message-State: AFuF++lf/gB3gwQ2roF770Xb3+Nu5mebhGggylN9oIPCMzpyOPcqCX2v ItEvzSc6+yUI47kdr9DBWBDU0aysWX5CE8xBPe+0/rp0uOacRbQ2ZYKdQYD46cMoLrk= X-Gm-Gg: AR+sD11Xj520RaWwmAG7VDK2GpFXe7Q22cFjIDtwE2NsY0+tZWofDNfc3g4rp38hisc AbXobOQ3vhMRsM/yE/CiGU4Slc9PniYJEr98Cg4hY0m+mHG/ANjLkYb6O5GnqF5RG42IdjBfcba 1J94bdKSy6mYumgy2jrPFgc11DPLq6ZJXKnN5Z6Agf9hV07hiATd2fTNTV6Orj1cnfMav2nYJdx Vec0YE+BCAVhwUEhaEhtR/76U8Tbp7kN24U5/E0sxkrAAuoS93ks7J+P9glgssYeROrXzle7h5y gcsgykS7K7cod3p0JLMBOV9taoTJs1jV4QW5TDXCmgUUN2PJDaSlJFTBxNHowfDvjiTvWhT1p8w gRnc8iRucsxHkIsLijysmC2WRcSMmaq9YPxcGEOdRqrTBtaLABx3tq573+/8512Aj7Ox5kDK7P6 JyNe8joHrZ+Vj4aoVCK+LsUTQ4lT0cdXRb/CLhbMHvOqgIOWZGkv6Suo6gOVmSTene17ajdGu8X b+sk6ypLy20aYZ3WZ5sJYvRvIhuV+vEnLka5l/cou3XQg== X-Received: by 2002:a05:6214:2584:b0:90c:c53c:a032 with SMTP id 6a1803df08f44-90ebabce888mr24156306d6.25.1788313899587; Tue, 01 Sep 2026 18:51:39 -0700 (PDT) Received: from ziepe.ca (hlfxns010zw-159-2-239-150.pppoe-dynamic.high-speed.ns.bellaliant.net. [159.2.239.150]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-90e9eef4f20sm7284946d6.41.2026.09.01.18.51.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Sep 2026 18:51:38 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1x1a8X-0000000Czw5-2tb4; Tue, 01 Sep 2026 22:51:37 -0300 Date: Tue, 1 Sep 2026 22:51:37 -0300 From: Jason Gunthorpe To: Nicolin Chen Cc: "Aneesh Kumar K.V" , linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexey Kardashevskiy , Catalin Marinas , Dan Williams , Joerg Roedel , Jonathan Cameron , Marc Zyngier , Pranjal Shrivastava , Robin Murphy , Samuel Ortiz , Steven Price , Suzuki K Poulose , Will Deacon , Xu Yilun Subject: Re: [RFC PATCH v4 03/16] iommu/arm-smmu-v3: Add initial pSMMU realm viommu plumbing Message-ID: <20260902015137.GA2890729@ziepe.ca> References: <20260427085344.941627-1-aneesh.kumar@kernel.org> <20260427085344.941627-4-aneesh.kumar@kernel.org> <20260901143445.GC56830@ziepe.ca> <20260901174230.GA2847102@ziepe.ca> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Sep 01, 2026 at 12:08:38PM -0700, Nicolin Chen wrote: > The viommu object here is an empty vehicle that almost has no use > but to allow another vehicle (vdevice) on top to forward vBDF. It > makes VMM code a bit awkward: there is no iommu instance, so VMM > doesn't enable iommu driver, then there is no good place to alloc > the viomu object for VIOMMU_TYPE_ARM_REALM_SMMUV3. It would have to allocate singletons viommu for each psmmu as part of setting up the vdevices. Somehow I'd rather the vmm deal with that then invent a whole new set of uapis and flows.. At best maybe we can invent a kernel side helper to create the singletons like the auto domains, but IDK if it is really so hard for the VMM (especially compared with how hard everything else is in CC) Jason