From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C844E199928 for ; Thu, 19 Sep 2024 09:12:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726737124; cv=none; b=lIk6FN14aMcY6ZfKQGuvmtTikGsoxnLbaB/qMhggpC/hjy8Gt58B+4dODtMUXhmzI1h4tYe6KimATb4TBH1rdvVbFl+Pc8xh5cSEtmTLqykK3E3mIKda1/WvbZXj4nC/A9uv/dpoJXy8M4/FNodNLkvqeWFBc014qmDUHW+hCfk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726737124; c=relaxed/simple; bh=6rAF1Svpd8vBBvWUfaNilf4YD3O1FlwDk4ri/1NJPB8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=faiBuz5tpTBSxxSlFDsXjaPm4hm/PvionAOSM7hipRFu/OGOw5uASkpnHhf7GApMRJgUCx+an5qQKm4q/9YcgJjLG0nXCKoAy867UaKADOm56mE5CrZnR3pGmVNl+rqcmRzjv/UhPkxDT+hFt6DCGWBVyPKQJPvN64EtWNRjpmY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=vPUhqOG+; arc=none smtp.client-ip=95.215.58.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="vPUhqOG+" Date: Thu, 19 Sep 2024 02:11:51 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1726737120; 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: in-reply-to:in-reply-to:references:references; bh=SDI9ysSiZI8BDMOOphPs7LmwKx7q2jcPwhENrySxiwA=; b=vPUhqOG+H9KeTsysJMAqMuCfqWmU7+3PlKqtZSPW8LoRbth3fH2oE43m92do6CRtAv7uN3 ZY78LLhPQ0YyxTsc1iu/RCkzUYZbGXbWSIyoLn4ZYvt9KP1Jg5nLLNyObcneQ6la+xKuvU tTo0PBflMSVYjvp6s3e+kGGLM7mMPxA= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Lilit Janpoladyan Cc: kvm@vger.kernel.org, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, nh-open-source@amazon.com, kvmarm@lists.linux.dev Subject: Re: [PATCH 0/8] *** RFC: ARM KVM dirty tracking device *** Message-ID: References: <20240918152807.25135-1-lilitj@amazon.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240918152807.25135-1-lilitj@amazon.com> X-Migadu-Flow: FLOW_OUT Hi Lilit, +cc kvmarm mailing list, get_maintainer is your friend :) On Wed, Sep 18, 2024 at 03:27:59PM +0000, Lilit Janpoladyan wrote: > An example of a device that tracks accesses to stage-2 translations and will > implement page_tracking_device interface is AWS Graviton Page Tracking Agent > (PTA). We'll be posting code for the Graviton PTA device driver in a separate > series of patches. In order to actually review these patches, we need to see an implementation of such a page tracking device. Otherwise it's hard to tell that the interface accomplishes the right abstractions. Beyond that, I have some reservations about maintaining support for features that cannot actually be tested outside of your own environment. > When ARM architectural solution (FEAT_HDBSS feature) is available, we intend to > use it via the same interface most likely with adaptations. Will the PTA stuff eventually get retired once you get support for FEAT_HDBSS in hardware? I think the best way forward here is to implement the architecture, and hopefully after that your legacy driver can be made to fit the interface. The FVP implements FEAT_HDBSS, so there's some (slow) reference hardware to test against. This is a very interesting feature, so hopefully we can move towards something workable. -- Thanks, Oliver