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

From: Jason Gunthorpe
Date: Mon May 02 2022 - 09:05:56 EST


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?

Jason