linux-kernel - Re: [RFC PATCH 2/2] vfio: Include no-iommu mode

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: <20151011092303.GA19867@scylladb.com>
Date:	Sun, 11 Oct 2015 12:23:03 +0300
From:	Gleb Natapov <gleb@...lladb.com>
To:	"Michael S. Tsirkin" <mst@...hat.com>
Cc:	Avi Kivity <avi@...lladb.com>,
	Alex Williamson <alex.williamson@...hat.com>,
	avi@...udius-systems.com, corbet@....net,
	bruce.richardson@...el.com, linux-kernel@...r.kernel.org,
	alexander.duyck@...il.com, gleb@...udius-systems.com,
	stephen@...workplumber.org, vladz@...udius-systems.com,
	iommu@...ts.linux-foundation.org, hjk@...sjkoch.de,
	gregkh@...uxfoundation.org
Subject: Re: [RFC PATCH 2/2] vfio: Include no-iommu mode

On Sun, Oct 11, 2015 at 12:19:54PM +0300, Michael S. Tsirkin wrote:
> > But since you must pass the same value to open(), you already know that
> > you're using noiommu.
> > 
> > >VFIO_IOMMU_MAP_DMA, VFIO_IOMMU_ENABLE and VFIO_IOMMU_DISABLE
> > >will probably also fail ...
> > >
> > 
> > Don't you have to call MAP_DMA to pin the memory?
> 
> Well check it out - the patch in question doesn't implement this ioctl.
> In fact it doesn't implement anything except CHECK_EXTENSION.
> 
> And this makes sense to me: MAP_DMA
> maps a virtual address to io address, and that doesn't
> work for the dummy iommu.
> 
> You can pin memory using many other ways, including
> mlock and hugetlbfs.
> 
mlock() does not pin memory.

--
			Gleb.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/