Re: swiotlb/caamjr regression (Was: [GIT PULL] (swiotlb) stable/for-linus-5.12)

From: Konrad Rzeszutek Wilk <konrad@darnok.org>
To: 'Dominique MARTINET' <dominique.martinet@atmark-techno.com>
Cc: "Chanho Park" <chanho61.park@samsung.com>,
	"'Jianxiong Gao'" <jxgao@google.com>,
	"'Christoph Hellwig'" <hch@lst.de>,
	"'Konrad Rzeszutek Wilk'" <konrad.wilk@oracle.com>,
	"'Linus Torvalds'" <torvalds@linux-foundation.org>,
	"'Horia Geantă'" <horia.geanta@nxp.com>,
	linux-kernel@vger.kernel.org,
	"'Lukas Hartmann'" <lukas@mntmn.com>,
	"'Aymen Sghaier'" <aymen.sghaier@nxp.com>,
	"'Herbert Xu'" <herbert@gondor.apana.org.au>,
	"'David S. Miller'" <davem@davemloft.net>,
	linux-crypto@vger.kernel.org, iommu@lists.linux-foundation.org,
	"'Marc Orr'" <marcorr@google.com>,
	"'Erdem Aktas'" <erdemaktas@google.com>,
	"'Peter Gonda'" <pgonda@google.com>,
	"'Bumyong Lee'" <bumyong.lee@samsung.com>
Subject: Re: swiotlb/caamjr regression (Was: [GIT PULL] (swiotlb) stable/for-linus-5.12)
Date: Mon, 21 Jun 2021 09:16:43 -0400	[thread overview]
Message-ID: <YNCROxI328u7IKdQ@fedora> (raw)
In-Reply-To: <YNASOEGsDxhFC8qJ@atmark-techno.com>

On Mon, Jun 21, 2021 at 01:14:48PM +0900, 'Dominique MARTINET' wrote:
> Chanho Park wrote on Mon, Jun 21, 2021 at 11:55:22AM +0900:
> > Sure. No problem. But, the patch was already stacked on Konrad's tree
> > and linux-next as well.
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb.git/commit/?h=devel/for-linus-5.14&id=33d1641f38f0c327bc3e5c21de585c77a6512bc6 
> 
> That patch is slightly different, it's a rewrite Konrad did that mixes
> in Linus' suggestion[1], which breaks things for the NVMe usecase
> Jianxiong Gao has.
> 
> [1] offset = (tlb_addr - mem->start) & (IO_TLB_SIZE - 1)
> 
> 
> Konrad is aware so I think it shouldn't be submitted :)

The beaty of 'devel' and 'linux-next' is that they can be reshuffled and
mangled. I pushed them original patch from Bumyong there and will let
it sit for a day and then create a stable branch and give it to Linus.

Then I need to expand the test-regression bucket so that this does not
happen again. Dominique, how easy would it be to purchase one of those
devices?

I was originally thinking to create a crypto device in QEMU to simulate
this but that may take longer to write than just getting the real thing.

Or I could create some fake devices with weird offsets and write a driver
for it to exercise this.. like this one I had done some time ago that
needs some brushing off.