Re: [PATCH 1/1] iommu/vt-d: Fix agaw for a supported 48 bit guest address width

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Aug 16, 2021 at 08:20:31PM +0800, Lu Baolu wrote:
> Hi Greg,
> 
> On 2021/8/16 19:48, Greg Kroah-Hartman wrote:
> > On Mon, Aug 16, 2021 at 07:39:32PM +0800, Lu Baolu wrote:
> > > From: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com>
> > > 
> > > [ Upstream commit 327d5b2fee91c404a3956c324193892cf2cc9528 ]
> > 
> > Also, this really does not look like this commit at all :(
> > 
> 
> This is not a back port. It's a fix for some stable kernels. Sorry for
> the confusion.
> 
> The error happens in a helper function that has been deprecated in the
> upstream kernel by above commit. I added below explanation in the commit
> message:
> 
> "
> This issue happens on the code path of getting a private domain for a
> device. A private domain was needed when the domain of an iommu group
> couldn't meet the requirement of a device. The IOMMU core has been
> evolved to eliminate the need for private domain, hence this code path
> has already been removed from the upstream since commit 327d5b2fee91c
> ("iommu/vt-d: Allow 32bit devices to uses DMA domain"). Instead of back
> porting all patches that are required for removing the private domain,
> this simply fixes it in the affected stable kernel between v4.16 and v5.7.
> "
> 
> I'm sorry if this is not the right way to do this.

Ah, sorry, I totally missed that.  This is fine, now queued up for
4.19.y and 5.4.y.

thanks,

greg k-h