From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from verein.lst.de (verein.lst.de [213.95.11.211])
	(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 0263037187B
	for <linux-kernel@vger.kernel.org>; Thu, 28 May 2026 08:43:06 +0000 (UTC)
Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211
ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;
	t=1779957788; cv=none; b=A5cZ3ycLDW1Sj54+ZZIAJI2D2pzqWIcBvIBZSwXFC3AHvd9seY03ek6/QJJlHnG9wYCahG63cTv1hr/H1BLwyMfzQagMsTqDCOdEmeEAEpCeO28dzdrGGtXzGXfjMOqjGaH7iDr6/ion4RNuCimZ5jgk7/G+Xz36ka1rIUslnC8=
ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org;
	s=arc-20240116; t=1779957788; c=relaxed/simple;
	bh=DGvf82Jw8NvfZ7cpwcGs2iTax4rt9ddm9t/f7Yr2LdM=;
	h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version:
	 Content-Type:Content-Disposition:In-Reply-To; b=bJ6yjr2R9m5QeI18N5hqWJ0iV8CDjpek23UamX09SMz7Nq3gb9P4B9kC8A+JEIGUDExQmHMsUxGUpfrhdCv+wGi9FWsm1j3uQYD6Kn9SUK0b3HZEJvajuji5WarXRgQc2tSOj63/qcy4UoA9l4DS3otWODS4iv3KhUWxvceTC1U=
ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211
Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de
Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de
Received: by verein.lst.de (Postfix, from userid 2407)
	id 2AAC468B05; Thu, 28 May 2026 10:43:04 +0200 (CEST)
Date: Thu, 28 May 2026 10:43:03 +0200
From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Chao Shi <coshi036@gmail.com>, linux-nvme@lists.infradead.org,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	Jens Axboe <axboe@kernel.dk>,
	Tatsuya Sasaki <tatsuya6.sasaki@kioxia.com>,
	Maurizio Lombardi <mlombard@arkamax.eu>,
	linux-kernel@vger.kernel.org, Sungwoo Kim <iam@sung-woo.kim>,
	Dave Tian <daveti@purdue.edu>, Weidong Zhu <weizhu@fiu.edu>
Subject: Re: [PATCH v5] nvme: reject passthrough of driver-managed Set
 Features
Message-ID: <20260528084303.GA8199@lst.de>
References: <20260523225629.3964037-1-coshi036@gmail.com> <ahcAaPTOH9ELlAA4@kbusch-mbp>
Precedence: bulk
X-Mailing-List: linux-kernel@vger.kernel.org
List-Id: <linux-kernel.vger.kernel.org>
List-Subscribe: <mailto:linux-kernel+subscribe@vger.kernel.org>
List-Unsubscribe: <mailto:linux-kernel+unsubscribe@vger.kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ahcAaPTOH9ELlAA4@kbusch-mbp>
User-Agent: Mutt/1.5.17 (2007-11-01)

On Wed, May 27, 2026 at 08:32:08AM -0600, Keith Busch wrote:
> On Sat, May 23, 2026 at 06:56:29PM -0400, Chao Shi wrote:
> > +			switch (le32_to_cpu(c->features.fid) & 0xff) {
> > +			case NVME_FEAT_KATO:
> > +				if (ctrl->ops->flags & NVME_F_FABRICS)
> > +					break;
> > +				fallthrough;
> > +			case NVME_FEAT_HOST_BEHAVIOR:
> > +			case NVME_FEAT_HOST_MEM_BUF:
> > +			case NVME_FEAT_NUM_QUEUES:
> > +			case NVME_FEAT_AUTO_PST:
> 
> I may have been overly restrictive with suggesting AUTO_PST for this
> filter. Messing with the other features will break something, but power
> state is just user policy. The driver may undo the user setting on a
> controller reset, but so what?

There's really no point in allowing it.  Just as we should have never
allowed low-level config of any kind, but unfortunately nvme admin
commands are a horrible grab all.