mpk: reenable MPK support with vendor string check #7513
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In bytecodealliance#7446 I disabled MPK support temporarily due to failures in CI runs. Looking into this further in bytecodealliance#7445, I discovered that it is due to how `has_cpuid_bit_set` works on different x86 machines: Intel's `CPUID` instruction reports support for MPK in a certain leaf bit, AMD does it some other (unknown?) way. The CI problem boiled down to occasional runs on AMD machines that would fail with `SIGILL` because the AMD machine reported that it had MPK support when it really did not. This change fixes the issue by first checking if the CPU vendor string is `GenuineIntel` before inspecting the MPK `CPUID` leaf bit. Closes bytecodealliance#7445.
alexcrichton
approved these changes
Nov 9, 2023
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In #7446 I disabled MPK support temporarily due to failures in CI runs. Looking into this further in #7445, I discovered that it is due to how
has_cpuid_bit_setworks on different x86 machines: Intel'sCPUIDinstruction reports support for MPK in a certain leaf bit, AMD does it some other (unknown?) way. The CI problem boiled down to occasional runs on AMD machines that would fail withSIGILLbecause the AMD machine reported that it had MPK support when it really did not. This change fixes the issue by first checking if the CPU vendor string isGenuineIntelbefore inspecting the MPKCPUIDleaf bit.Closes #7445.