From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f182.google.com (mail-qt1-f182.google.com [209.85.160.182]) (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 ECF521CA92 for ; Tue, 16 Jan 2024 17:22:14 +0000 (UTC) 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; arc=none smtp.client-ip=209.85.160.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705425736; cv=none; b=rNgtk9cAk012gvygXY1YG+xKmHHig0SXskPXHQ5exBAhrtdbwa+dL/Dex5Yp8CWlKZ0A6niNQMQJKTqoj7gj2PfrY3DBx3FCIZA6PvOt0Ba7F5+coTXguVscw3a/kHmOwN5X3dlewI3oR4zbUFZokvuCQJsDiIx5No8HA1mgWTw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705425736; c=relaxed/simple; bh=aYK0pXUCQDuWqK9h1FN+gk+wNlGZ4DmYNR3Rcj4LiQM=; h=Received:DKIM-Signature:X-Google-DKIM-Signature: X-Gm-Message-State:X-Google-Smtp-Source:X-Received:Received: Received:Date:From:To:Cc:Subject:Message-ID:References: MIME-Version:Content-Type:Content-Disposition:In-Reply-To; b=g6yQBbHlb3nEOVtO2EDzZXoxKOWP6btTJfiIkc/vFaBGwNaMd+TakOh+5XsolI52QlyHorH/Sc5ASSnqnsn3VEnqj7GdkjMut3hRGCOC89f7I+rUTIB5444/z7UNtx1ArZAjRkFnRmfFcAoVcahorKxbMlcn0gywoD2KHqwwPpc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b=AnAVyu03; arc=none smtp.client-ip=209.85.160.182 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="AnAVyu03" Received: by mail-qt1-f182.google.com with SMTP id d75a77b69052e-429be9fe952so38207711cf.0 for ; Tue, 16 Jan 2024 09:22:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1705425733; x=1706030533; darn=lists.linux.dev; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=5/brWcTdNs+6S2k/yrCHCfUU2lKmPGBcNCKNqgF66R0=; b=AnAVyu03g8T2Ebw2gntEOq+sy3lpz67jFSrsbsqoljt92lY4mXyDhtRt+EQaQgT6lr 1rE2PtDQbM/VYe/7YY1G14HPgrj/mif1MerlxrThUyW62MPwkYBEX9nhLabCpri+sduN uOhCYIp0ls2HhzfI7R2ivnqB9dS+O2J/y3WN6mTEC7DsW9A+XYtrqaYOCaKTHuGupv/Z v7An6fIVWNLgo67LZJcWoKF4vQYE7OnKTzQpOLQoIJlo7Ty61G+L70/K4+DdvyFYz6l6 pVFUkfG/bXSBhs++mIyjzMw2akI6sAI8Tv09rLGa8vDktmHk7EJb4eCEaXZ5Ec2hP6KE 4ZZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705425733; x=1706030533; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=5/brWcTdNs+6S2k/yrCHCfUU2lKmPGBcNCKNqgF66R0=; b=JnUtQZpCXaLqHKbRD/h7uVVFOnH7TLtS4i+XRS8/U5jUNAgs9tx10OXfZ0chxDxOz1 9C+igpVRyOjpvse4keE3EXS0Z/5Ahvr7TDPVfIHajz4tLDY30YC3s33mx2QzFoS8xaRT Ebq1CB8rIfOIQFe2ERJuVGFPc8V8JKVzrVbKnLIJ4VewyqdclbHlCNYMl7T2yG/aybx3 6rcP8JrWRchiUIqU+K+Gz3AjAyo6ZfZLOzpCL8hf2Sgqsx3vOZ7+9RGUu9IimQ+U3Ttr 66q5cdvwXMDFIjJCFdI97PVEbfhFKHUrSpO4eJ/esYp7ULkl9CExGg/Df8sTR1k5pCwc baww== X-Gm-Message-State: AOJu0YxcmzSJn/PFjH5rZr5NNwLroUHsU5n/wmF0upOiNZ3m7SWPJ7W3 RuZMV+U0qMcCEs/kLtMPuQ9jGYC1PnZ3BA== X-Google-Smtp-Source: AGHT+IEqX6FBlJcqIURQNWdMB4Pjrd+85tT1vjPWzBCDLpIX3WTAFh+m0WiWcCtR2bz4jTiceZxLKg== X-Received: by 2002:ac8:5b8a:0:b0:42a:c2b:adc6 with SMTP id a10-20020ac85b8a000000b0042a0c2badc6mr324639qta.40.1705425733751; Tue, 16 Jan 2024 09:22:13 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-68-80-239.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.68.80.239]) by smtp.gmail.com with ESMTPSA id r13-20020a05620a03cd00b0078326257ab7sm3872984qkm.37.2024.01.16.09.22.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jan 2024 09:22:13 -0800 (PST) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1rPn8e-0046hz-P7; Tue, 16 Jan 2024 13:22:12 -0400 Date: Tue, 16 Jan 2024 13:22:12 -0400 From: Jason Gunthorpe To: Vasant Hegde Cc: iommu@lists.linux.dev, joro@8bytes.org, suravee.suthikulpanit@amd.com, wei.huang2@amd.com, jsnitsel@redhat.com, Baolu Lu Subject: Re: [PATCH v4 07/16] iommu/amd: Introduce per-device domain ID to workaround potential TLB aliasing issue Message-ID: <20240116172212.GG50608@ziepe.ca> References: <20231212085224.6985-1-vasant.hegde@amd.com> <20231212085224.6985-8-vasant.hegde@amd.com> <20240105185549.GM50608@ziepe.ca> <20240111135952.GV50608@ziepe.ca> <0215990a-dff1-c6c3-bfa1-c90fa63b0c7b@amd.com> <20240112145934.GY50608@ziepe.ca> <5d0f4146-fb57-d700-1263-881e2ec3ded7@amd.com> <20240116140049.GD50608@ziepe.ca> <2fa63c4c-28bb-246d-300b-852db447a3c7@amd.com> Precedence: bulk X-Mailing-List: iommu@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: <2fa63c4c-28bb-246d-300b-852db447a3c7@amd.com> On Tue, Jan 16, 2024 at 10:38:16PM +0530, Vasant Hegde wrote: > Joson, > > > On 1/16/2024 7:30 PM, Jason Gunthorpe wrote: > > On Tue, Jan 16, 2024 at 04:22:16PM +0530, Vasant Hegde wrote: > > > >>> The *device* has a list of PASID's that point to iommu_domains. This > >>> is stored in an xarray inside the iommu_group. > >>> > >>> The *iommu_domain* has a list of *devices & PASIDs* that can use this > >>> domain for translation (ie that it was attached to) > >> > >> IIUC domain will be having device/PASID combination something like below: > >> > >> UNMANAGED_DOMAIN_A with IO Page table : > >> - DevA + PASID zero (say non PASID capable device) > >> - devB + PASID > >> - devC + PASID > >> > >> We will *not* have same device with different PASID in same domain like > >> - DevB + PASID M > >> - DevB + PASID N > >> > >> Is that correct? > > > > No, all combinations are allowed in the API. > > What is the use case for same device with two or more different PASID to point > to same page table? Possibly something with SIOV like techniques where you have two virtual functions, each being DMA isolated with PASID, installed into the same VM. The guest physical map would be the same iommu_domain but the PASID would be different. Regardless, the API doesn't require this and I don't want to see drivers inventing their own restrictions without a reason.. Jason