10 Jul
2025
10 Jul
'25
3:35 p.m.
On Thu, Jul 10, 2025 at 08:28:08AM -0700, Jacob Pan wrote:
why would IOMMU cache all the entries if the walk is not successful?
Sadly, because nothing in the architecture said not to..
Also, per x86 vm map how could this example (UUUUS) happen to SVA? i.e. sharing intermediate levels.
ffffc90000000000 | -55 TB | ffffe8ffffffffff | 32 TB | vmalloc/ioremap 0000000000000000 | 0 | 00007fffffffffff | 128 TB | user-space
Because Linux only uses the leaf U/S bit, the interior bits are set to not-override the leaf.
Jason