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| author |   patrick <patrick@openbsd.org> | 2021-04-03 15:59:08 +0000 |
|---|---|---|
| committer | patrick <patrick@openbsd.org> | 2021-04-03 15:59:08 +0000 |
| commit | a5eb7f55b9c1dc179deb7da5fa31c6889c73c8ca (patch) | |
| tree | 1aaebdf7ef6cfad3540cacbb308660aaea1007c9 /gnu/llvm/clang/lib/Basic/Module.cpp | |
| parent | Exclude the first page from I/O virtual address space, which is the NULL (diff) | |
| download | wireguard-openbsd-a5eb7f55b9c1dc179deb7da5fa31c6889c73c8ca.tar.xz wireguard-openbsd-a5eb7f55b9c1dc179deb7da5fa31c6889c73c8ca.zip | |
Add a guard page between I/O virtual address space allocations. The idea
is that IOVA allocations always have a gap in-between which produces a fault
on access. If a transfer to a given allocation runs further than expected
we should be able to see it. We pre-allocate IOVA on bus DMA map creation,
and as long as we don't allocate a PTE descriptor, this comes with no cost.
We have plenty of address space anyway, so adding a page-sized gap does not
hurt at all and can only have positive effects.
Idea from kettenis@
Diffstat (limited to 'gnu/llvm/clang/lib/Basic/Module.cpp')
0 files changed, 0 insertions, 0 deletions