linux-kernel - Re: [PATCH] VFIO driver: Non-privileged user level PCI drivers

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]

Date:	Tue, 01 Jun 2010 13:28:48 +0300
From:	Avi Kivity <avi@...hat.com>
To:	"Michael S. Tsirkin" <mst@...hat.com>
CC:	Tom Lyon <pugs@...co.com>, linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org, chrisw@...s-sol.org, joro@...tes.org,
	hjk@...utronix.de, gregkh@...e.de, aafabbri@...co.com,
	scofeldm@...co.com
Subject: Re: [PATCH] VFIO driver: Non-privileged user level PCI drivers

On 06/01/2010 12:55 PM, Michael S. Tsirkin wrote:
>
>>   It can't program the iommu.
>> What
>> the patch proposes is that userspace tells vfio about the needed
>> mappings, and vfio programs the iommu.
>>      
> There seems to be some misunderstanding.  The userspace interface
> proposed forces a separate domain per device and forces userspace to
> repeat iommu programming for each device.  We are better off sharing a
> domain between devices and programming the iommu once.
>    

   iommufd = open(/dev/iommu);
   ioctl(iommufd, IOMMUFD_ASSIGN_RANGE, ...)
   ioctl(vfiofd, VFIO_SET_IOMMU, iommufd)

?

If so, I agree.

> The natural way to do this is to have an iommu driver for programming
> iommu.
>
> This likely means we will have to pass the domain to 'vfio' or uio or
> whatever the driver that gives userspace the access to device is called,
> but this is only for security, there's no need to support programming
> iommu there.
>
> And using this design means the uio framework changes
> required would be minor, so we won't have to duplicate code.
>    

Since vfio would be the only driver, there would be no duplication.  But 
a separate object for the iommu mapping is a good thing.  Perhaps we can 
even share it with vhost (without actually using the mmu, since vhost is 
software only).

-- 
error compiling committee.c: too many arguments to function

--
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/