[PATCH V3 0/3] iommu: Add support to change default domain of an iommu

Prakhya, Sai Praneeth sai.praneeth.prakhya at intel.com
Fri May 29 04:46:38 UTC 2020


Hi Baolu,

> -----Original Message-----
> From: Lu Baolu <baolu.lu at linux.intel.com>
> Sent: Thursday, May 28, 2020 6:52 PM
> To: Prakhya, Sai Praneeth <sai.praneeth.prakhya at intel.com>;
> iommu at lists.linux-foundation.org
> Cc: baolu.lu at linux.intel.com; Christoph Hellwig <hch at lst.de>; Joerg Roedel
> <joro at 8bytes.org>; Raj, Ashok <ashok.raj at intel.com>; Will Deacon
> <will.deacon at arm.com>; Mehta, Sohil <sohil.mehta at intel.com>; Robin
> Murphy <robin.murphy at arm.com>; Jacob Pan <jacob.jun.pan at linux.intel.com>
> Subject: Re: [PATCH V3 0/3] iommu: Add support to change default domain of
> an iommu
> 
> Hi Sai,
> 
> On 5/29/20 3:23 AM, Sai Praneeth Prakhya wrote:
> > Presently, the default domain of a iommu group is allocated during
> > boot time and it cannot be changed later. So, the device would
> > typically be either in identity
> > (pass_through) mode or the device would be in DMA mode as long as the
> > system is up and running. There is no way to change the default domain
> > type dynamically i.e. after booting, a device cannot switch between identity
> mode and DMA mode.
> >
> > Assume a use case wherein the privileged user would want to use the
> > device in pass-through mode when the device is used for host so that
> > it would be high performing. Presently, this is not supported. Hence
> > add support to change the default domain of an iommu group dynamically.
> >
> > Support this by writing to a sysfs file, namely
> > "/sys/kernel/iommu_groups/<grp_id>/type".
> 
> The email subject
> 
> [PATCH V3 0/3] iommu: Add support to change default domain of an iommu
> 
> probably should be changed to
> 
> [PATCH V3 0/3] iommu: Add support to change default domain of an iommu
> group

Oops.. my bad. I have it in the patches that I have on my dev machine. I added "group" to a new line because the subject line crossed 80 character limit. Probably, I will just put it in the same line for the next version. Thanks for bringing this up.

Regards,
Sai


More information about the iommu mailing list