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Date: Tue, 19 May 2026 09:14:48 +0200
From: Christoph Hellwig <hch@lst.de>
To: Chao Shi <coshi036@gmail.com>
Cc: linux-nvme@lists.infradead.org, Keith Busch <kbusch@kernel.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 v2] nvme: reserve a keep-alive admin tag for all
 transports
Message-ID: <20260519071448.GA9841@lst.de>
References: <20260515071248.2689513-1-coshi036@gmail.com>
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On Fri, May 15, 2026 at 03:12:48AM -0400, Chao Shi wrote:
> A quirk-based approach was considered but no PCIe controller
> documented to declare KAS != 0 was found (two enterprise SSDs tested
> locally report KAS=0), so an allowlist has no entries today.

Quirking for spec allowed behavior sounds odd.  If we care about
testing KA for PCIe it should be trivial to implement in nvmet-epf
in the kernel, but I'm not sure there is much of a point in that.

> Reproducer (run as root on an unpatched kernel with a PCIe NVMe device):

Can you wire this up as a testcase in blktests?

The patch itself looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>