Re: [PATCH 1/1] iommu/amd: Preserve default DTE fields when updating Host Page Table Root

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, Feb 26, 2025 at 11:19:46AM -0500, Alejandro Jimenez wrote:
> On 1/7/25 13:01, Jason Gunthorpe wrote:
> > On Tue, Jan 07, 2025 at 05:45:38PM +0530, Vasant Hegde wrote:
> > > > @@ -2052,12 +2052,12 @@ static void set_dte_entry(struct amd_iommu *iommu,
> > > >   	make_clear_dte(dev_data, dte, &new);
> > > 
> > > This fix is fine. But with all changes we have done in this code does, do we
> > > really need make_clear_dte()?
> > 
> > > How about removing `make_clear_dte()` and moving DTE_FLAG_V to
> > > write_dte_lower128() ?
> > 
> > The V flag should just be set by the functions building the DTE,
> > write_dte_lower() should accept a fully formed dte as a matter of
> > layering.
> > 
> > I'm hopefull Suravee will come with something like this:
> > 
> > https://lore.kernel.org/linux-iommu/20241016142237.GP3559746@nvidia.com/
> > 
> 
> Suravee did say he would implement the suggestions above in the series for
> nested translation support, but that might take a while considering where
> we are in the cycle. Given that this fix is straightforward and has been
> reviewed by Dheeraj, are there any concerns with merging it in its current
> form?

+1 to take the fix

Jason