linux-kernel - Re: [PATCH v7 20/21] PCI/P2PDMA: Introduce pci_mmap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YsRzNqmZYlgkL7fI@kroah.com>
Date:   Tue, 5 Jul 2022 19:21:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Christoph Hellwig <hch@....de>
Cc:     Logan Gunthorpe <logang@...tatee.com>,
        Jason Gunthorpe <jgg@...pe.ca>, linux-kernel@...r.kernel.org,
        linux-nvme@...ts.infradead.org, linux-block@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-mm@...ck.org,
        iommu@...ts.linux-foundation.org,
        Stephen Bates <sbates@...thlin.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Christian König <christian.koenig@....com>,
        John Hubbard <jhubbard@...dia.com>,
        Don Dutile <ddutile@...hat.com>,
        Matthew Wilcox <willy@...radead.org>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Minturn Dave B <dave.b.minturn@...el.com>,
        Jason Ekstrand <jason@...kstrand.net>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Xiong Jianxin <jianxin.xiong@...el.com>,
        Bjorn Helgaas <helgaas@...nel.org>,
        Ira Weiny <ira.weiny@...el.com>,
        Robin Murphy <robin.murphy@....com>,
        Martin Oliveira <martin.oliveira@...eticom.com>,
        Chaitanya Kulkarni <ckulkarnilinux@...il.com>,
        Ralph Campbell <rcampbell@...dia.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH v7 20/21] PCI/P2PDMA: Introduce pci_mmap_p2pmem()

On Tue, Jul 05, 2022 at 06:50:39PM +0200, Christoph Hellwig wrote:
> [note for the newcomers, this is about allowing mmap()ing the PCIe
> P2P memory from the generic PCI P2P code through sysfs, and more
> importantly how to revoke it on device removal]

We allow mmap on PCIe config space today, right?  Why is this different
from what pci_create_legacy_files() does today?

> On Tue, Jul 05, 2022 at 10:44:49AM -0600, Logan Gunthorpe wrote:
> > We might be able to. I'm not sure. I'll have to figure out how to find
> > that inode from the p2pdma code. I haven't found an obvious interface to
> > do that.
> 
> I think the right way to approach this would be a new sysfs API
> that internally calls unmap_mapping_range internally instead of
> exposing the inode. I suspect that might actually be the right thing
> to do for iomem_inode as well.

Why do we need something new and how is this any different from the PCI
binary files I mention above?  We have supported PCI hotplug for a very
long time, do the current PCI binary sysfs files not work properly with
mmap and removing a device?

thanks,

greg k-h