From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f173.google.com (mail-qk1-f173.google.com [209.85.222.173]) (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 4514B22A7E2 for ; Thu, 16 Jan 2025 19:19:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737055195; cv=none; b=iiV2Vaho7rQ2mskdLgPOEprw9TK+kSwa2W1+F65fFlm54d1STLR0MN9RsZ9vS6EgH8x9Dt89Fpek3qYjC03k4+Z3hqgT5bdc5XQVMH9XSQb08Jor7nAZihwQxIf3Ct3lI75d9rzgwXcYD3wOtP5pfmfdsdBsXHliHrvZ3Q4UzDk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737055195; c=relaxed/simple; bh=bChrpxoXYLOi2YUup3iemrrMhFmpTodAygOPpJhId9Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=j87EFziwiiZzO8qc4VE8lQdjcqXqVTADmRzolJJJLHVqjjYEfMHOY74whWuArDGvTP9ivCObirGJfw9DxHaBFzh35zINH/9bWAz4O4EMHZoSbv3gKdYoDCAaBsslPWV+/WgLAkJsQbOGD43OqBuUCT3bnxP8LNO+JPGyX6B2ehs= 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=G49tWjEA; arc=none smtp.client-ip=209.85.222.173 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="G49tWjEA" Received: by mail-qk1-f173.google.com with SMTP id af79cd13be357-7b6f1be1daeso120047785a.0 for ; Thu, 16 Jan 2025 11:19:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1737055193; x=1737659993; darn=lists.linux.dev; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=bChrpxoXYLOi2YUup3iemrrMhFmpTodAygOPpJhId9Y=; b=G49tWjEALMsHRg+7TOZCK5Xpr5trL2L3J3rEva4cWATLUB2G/gkte4xsdBcN1i4UZ+ 4rSH8++pEjGsO2IjpARJn0irCOhB8tT9oA4vh1Ph9oyJCZGYnJ35sT5MPxACtejyQLUX fWXsuLsATiNxoQuS5a/uGzSAd4UJlsCBxDD2mNHgx6uJUXzzHNrtaWH8Nk/s8ThWG7/P cdKD7uzhSU76XIPy7L+Eef8GP8BiGSMRWYlv9Ktqc6VF5o229juI1NZkWbICfUAtGhzu hoKL9piOr8DEzo0MM0/y4ZsP/d0mIF4Zk4EZXjAeXCwTj2/irk/vMg1yC3Zyf6FtTjud ryWQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1737055193; x=1737659993; h=in-reply-to:content-transfer-encoding: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=bChrpxoXYLOi2YUup3iemrrMhFmpTodAygOPpJhId9Y=; b=pyqiEtaq2oHS/6Z0E1NBja9HCT5BeNaZWp7ARCVza/6lzpe/Ga8giL5A3/ORQMt2Sy WrzP3aiS6qgKl/b8HTHbX9lDTwgcN14dlVXXNs2BWWAjjK0mxekKL7vpwmcKorM7gYAh F/jECAfSt3PrzpE2Rf8riGj1ZpsGAdrrnBA9X6Lc9psGZd5sk0WcNEILG9kYM6cVcZBf 1rKA/brb2jG/7rdz6sdDzFOfPq3yGlbr3lm1l4n4WEgfOpD9NUrD3bjGx6G9MSitOVMx rWQKjVhewZAQZ8zT/ulyvIjlIJm+zPD3CXO++9gFroXP+FlFS81NAmzxf2GLtXephNXb 7zlg== X-Forwarded-Encrypted: i=1; AJvYcCXAVIhzboqx5C1uT/vdn+slYRr0gCulg+Er3wxtQVw+tHSkRwmEb+ZrC3qIv2x6BPfkOE2llng=@lists.linux.dev X-Gm-Message-State: AOJu0YxQAoHVNcUjWtHAjgYd7gV1kAcfnLRVBvRm1WVh0rLG/Ape4TKh X1Imb/eNm8yNDM8K90AiBP6P5ARR9TIVNWbL7lModBs21bCeT4TPZ+ijqBwvhe8= X-Gm-Gg: ASbGncvpUjbfUVb3AH7GTKARVx43t6gfqGTcKCfVIb/N+dbqtO9TWGZnwQkLUh3MpIB W79Wt5YSQ9WUMSZ1J1Y2iLjZld+AVFhARiRWjEvvLmZUnbzFHH3TC/ZTViKmFNHTy1PJCiWLiXV sDwWbf+8uPZDvETgvsu06XgnNVobTQa9Fb08K/dWbNaBHc19ASlIxYFv3nN75lugiy7Y5g3mpGr Fqm7QA99kyy3jzIkVeeOPP0LYTG6l0+uvisiQSZ5X371SSM9Q7kwsibcOSCpfuLO/K2k7qXgIuO QJC0aTGUaUH2nIGj3o8UXukmR/MTRQ== X-Google-Smtp-Source: AGHT+IGTm4bFEwhL8GqLcY8z3nt0mSjwsh1Z+7KfLW6eIDlz0sFoLhtw28pz+YDUvgq5sFx2TdqJnA== X-Received: by 2002:a05:620a:2a13:b0:7b6:d8aa:7ef9 with SMTP id af79cd13be357-7be6320c0f9mr4896085a.32.1737055193220; Thu, 16 Jan 2025 11:19:53 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-68-128-5.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.68.128.5]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7be6147f2e7sm33743585a.32.2025.01.16.11.19.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Jan 2025 11:19:52 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1tYVPE-00000002xf3-0us0; Thu, 16 Jan 2025 15:19:52 -0400 Date: Thu, 16 Jan 2025 15:19:52 -0400 From: Jason Gunthorpe To: Mostafa Saleh Cc: iommu@lists.linux.dev, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, robdclark@gmail.com, joro@8bytes.org, robin.murphy@arm.com, jean-philippe@linaro.org, nicolinc@nvidia.com, vdonnefort@google.com, qperret@google.com, tabba@google.com, danielmentz@google.com, tzukui@google.com Subject: Re: [RFC PATCH v2 00/58] KVM: Arm SMMUv3 driver for pKVM Message-ID: <20250116191952.GD674319@ziepe.ca> References: <20241212180423.1578358-1-smostafa@google.com> <20241212194119.GA4679@ziepe.ca> <20250102201614.GA26854@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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Wed, Jan 08, 2025 at 12:09:53PM +0000, Mostafa Saleh wrote: > I am open to gradually upstream this as you mentioned where as a first > step pKVM would establish DMA isolation without translation for host, > that should be enough to have functional pKVM and run protected workloads. Personally I hate these giant patch series, you should strip it down to small meaningful steps and try to stay below 20 per series. I think getting pkvm to own the SMMU HW is a great first step that everything else can build on > But although that might be usable on some systems, I don’t think that’s > practical in the long term as it limits the amount of HW that can run pKVM. I suspect you will end up doing everything. Old HW needs paravirt, new HW will want nesting and its performance. Users other than mobile will come. If we were to use pKVM on server workloads we need nesting for performance. Jason