Re: [PATCH 2/5] iommu/vt-d: Set SNP bit only in second-level page table entries

[Baolu Lu]

Hi Jason,

On 2022/5/2 21:05, Jason Gunthorpe wrote:
> On Sun, May 01, 2022 at 07:24:31PM +0800, Lu Baolu wrote:
> > The SNP bit is only valid for second-level PTEs. Setting this bit in the
> > first-level PTEs has no functional impact because the Intel IOMMU always
> > ignores the same bit in first-level PTEs. Anyway, let's check the page
> > table type before setting SNP bit in PTEs to make the code more readable.
> Shouldn't this be tested before setting force_snooping and not during
> every map?

The check is in the following patch. This just makes sure that SNP is
only set in second-level page table entries.

Best regards,
baolu