linux-kernel - Re: [PATCH 06/12] IB/core: Add optional PCI P2P flag to rdma_rw_ctx

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: <7d276107-d2ae-530b-3d56-e104e22b4eea@deltatee.com>
Date:   Mon, 8 Jan 2018 12:05:57 -0700
From:   Logan Gunthorpe <logang@...tatee.com>
To:     Christoph Hellwig <hch@....de>
Cc:     Jason Gunthorpe <jgg@...pe.ca>, linux-kernel@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-nvme@...ts.infradead.org,
        linux-rdma@...r.kernel.org, linux-nvdimm@...ts.01.org,
        linux-block@...r.kernel.org, Stephen Bates <sbates@...thlin.com>,
        Jens Axboe <axboe@...nel.dk>,
        Keith Busch <keith.busch@...el.com>,
        Sagi Grimberg <sagi@...mberg.me>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Max Gurtovoy <maxg@...lanox.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Jérôme Glisse <jglisse@...hat.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>
Subject: Re: [PATCH 06/12] IB/core: Add optional PCI P2P flag to
 rdma_rw_ctx_[init|destroy]()



On 08/01/18 11:57 AM, Christoph Hellwig wrote:
> It does, sort of - but in a different way then the normal DMA map
> ops.  And only to work around the fact that we need to map our
> P2P space into struct pages.  Without that we could just pass the
> bus address around, but the Linux stack and VM isn't anywhere near
> ready for something that advanced.

Yeah, wouldn't that be nice.

Ok, so if we shouldn't touch the dma_map infrastructure how should the 
workaround to opt-out HFI and QIB look? I'm not that familiar with the 
RDMA code.

Thanks,

Logan