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x86 fails all tests if CONFIG_X86_KPTI is disabled #29175

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andrewboie opened this issue Oct 13, 2020 · 0 comments · Fixed by #29411
Closed

x86 fails all tests if CONFIG_X86_KPTI is disabled #29175

andrewboie opened this issue Oct 13, 2020 · 0 comments · Fixed by #29411
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@andrewboie
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area: Memory Protection area: X86 x86 Architecture (32-bit) area: X86_64 x86-64 Architecture (64-bit) bug The issue is a bug, or the PR is fixing a bug priority: medium Medium impact/importance bug

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@andrewboie
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andrewboie commented Oct 13, 2020 •
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Describe the bug
If kernel page table isolation (KPTI) is disabled, the memory management code doesn't work. This may have been bit-rotten for a while, we were lacking test coverage.

To Reproduce
This PR illustrates the problem:
#28800

Build tests with the new qemu_x86_nokpti or qemu_x86_64_nokpti targets.

Expected behavior
All tests pass.

Impact
x86 CPUs not susceptible to Meltdown cannot disable this feature and enjoy the considerable performance benefits.
@andrewboie andrewboie added bug The issue is a bug, or the PR is fixing a bug priority: medium Medium impact/importance bug area: X86 x86 Architecture (32-bit) area: Memory Protection area: X86_64 x86-64 Architecture (64-bit) labels Oct 13, 2020
@andrewboie andrewboie self-assigned this Oct 13, 2020
@andrewboie andrewboie mentioned this issue Oct 21, 2020
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area: Memory Protection area: X86 x86 Architecture (32-bit) area: X86_64 x86-64 Architecture (64-bit) bug The issue is a bug, or the PR is fixing a bug priority: medium Medium impact/importance bug
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x86: support single or per-domain page tables andrewboie/zephyr
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@andrewboie