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Date: Thu, 15 Feb 2024 16:35:45 +0000
From: Will Deacon <will@kernel.org>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: sagi@grimberg.me, hch@lst.de, axboe@kernel.dk, kbusch@kernel.org,
	joro@8bytes.org, robin.murphy@arm.com, jgg@nvidia.com,
	linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
	iommu@lists.linux.dev, murphyt7@tcd.ie, baolu.lu@linux.intel.com
Subject: Re: [PATCH v1 0/2] nvme-pci: Fix dma-iommu mapping failures when
 PAGE_SIZE=64KB
Message-ID: <20240215163544.GA821@willie-the-truck>
References: <cover.1707851466.git.nicolinc@nvidia.com>
 <20240214164138.GA31927@willie-the-truck>
 <Zc0bLAIXSAqsQJJv@Asurada-Nvidia>
 <20240215142208.GA753@willie-the-truck>
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On Thu, Feb 15, 2024 at 02:22:09PM +0000, Will Deacon wrote:
> On Wed, Feb 14, 2024 at 11:57:32AM -0800, Nicolin Chen wrote:
> > On Wed, Feb 14, 2024 at 04:41:38PM +0000, Will Deacon wrote:
> > > On Tue, Feb 13, 2024 at 01:53:55PM -0800, Nicolin Chen wrote:
> > And it seems to get worse, as even a 64KB mapping is failing:
> > [    0.239821] nvme 0000:00:01.0: swiotlb buffer is full (sz: 65536 bytes), total 32768 (slots), used 0 (slots)
> > 
> > With a printk, I found the iotlb_align_mask isn't correct:
> >    swiotlb_area_find_slots:alloc_align_mask 0xffff, iotlb_align_mask 0x800
> > 
> > But fixing the iotlb_align_mask to 0x7ff still fails the 64KB
> > mapping..
> 
> Hmm. A mask of 0x7ff doesn't make a lot of sense given that the slabs
> are 2KiB aligned. I'll try plugging in some of the constants you have
> here, as something definitely isn't right...

Sorry, another ask: please can you print 'orig_addr' in the case of the
failing allocation?

Thanks!

Will