Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) client-ip=2620:137:e000::3:4;
Date:   Tue, 28 Nov 2023 08:16:10 +0100
From:   Petr =?UTF-8?B?VGVzYcWZw61r?= <petr@tesarici.cz>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Halil Pasic <pasic@linux.ibm.com>,
        Niklas Schnelle <schnelle@linux.ibm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Petr Tesarik <petr.tesarik1@huawei-partners.com>,
        Ross Lagerwall <ross.lagerwall@citrix.com>,
        linux-pci <linux-pci@vger.kernel.org>,
        linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
        Matthew Rosato <mjrosato@linux.ibm.com>,
        Jianxiong Gao <jxgao@google.com>
Subject: Re: Memory corruption with CONFIG_SWIOTLB_DYNAMIC=y
Message-ID: <20231128081610.5616ef14@meshulam.tesarici.cz>
In-Reply-To: <20231127155913.GA1468@lst.de>
References: <104a8c8fedffd1ff8a2890983e2ec1c26bff6810.camel@linux.ibm.com>
        <20231103171447.02759771.pasic@linux.ibm.com>
        <20231103214831.26d29f4d@meshulam.tesarici.cz>
        <20231107182420.0bd8c211.pasic@linux.ibm.com>
        <20231108101347.77cab795@meshulam.tesarici.cz>
        <20231123111608.17727968@meshulam.tesarici.cz>
        <20231127155913.GA1468@lst.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Mon, 27 Nov 2023 16:59:13 +0100
Christoph Hellwig <hch@lst.de> wrote:

> On Thu, Nov 23, 2023 at 11:16:08AM +0100, Petr Tesa=C5=99=C3=ADk wrote:
> > > To sum it up, there are two types of alignment:
> > >=20
> > > 1. specified by a device's min_align_mask; this says how many low
> > >    bits of a buffer's physical address must be preserved,
> > >=20
> > > 2. specified by allocation size and/or the alignment parameter;
> > >    this says how many low bits in the first IO TLB slot's physical
> > >    address must be zero. =20
>=20
> Both are correct.

Great! Thank you for confirmation. Unfortunately, that's not quite how
the code works now.

I'm on it to fix things.

Petr T