From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@lst.de>
Date: Fri, 04 Mar 2022 17:28:59 +0000
Subject: Re: [PATCH 11/12] swiotlb: merge swiotlb-xen initialization into swiotlb
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To: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>, Christoph Hellwig <hch@lst.de>, iommu@lists.linux-foundation.org, x86@kernel.org, Anshuman Khandual <anshuman.khandual@arm.com>, Tom Lendacky <thomas.lendacky@amd.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Juergen Gross <jgross@suse.com>, Joerg Roedel <joro@8bytes.org>, David Woodhouse <dwmw2@infradead.org>, Lu Baolu <baolu.lu@linux.intel.com>, Robin Murphy <robin.murphy@arm.com>, linux-arm-kernel@lists.infradead.org, xen-devel@lists.xenproject.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-hyperv@vger.kernel.org, tboot-devel@lists.sourceforge.net, linux-pci@vger.kernel.org

On Wed, Mar 02, 2022 at 08:15:03AM -0500, Boris Ostrovsky wrote:
> Not for me, I fail to boot with
>
> [   52.202000] bnxt_en 0000:31:00.0: swiotlb buffer is full (sz: 256 bytes), total 0 (slots), used 0 (slots)
>
> (this is iscsi root so I need the NIC).
>
>
> I bisected it to "x86: remove the IOMMU table infrastructure" but haven't actually looked at the code yet.

That looks like the swiotlb buffer did not get initialized at all, but I
can't really explain why.

Can you stick in a printk and see if xen_swiotlb_init_early gets called
at all?