Rich Ercolani 277f2e587b Avoid save/restoring AMX registers to avoid a SPR erratum ... Intel SPR erratum SPR4 says that if you trip into a vmexit while doing FPU save/restore, your AMX register state might misbehave... and by misbehave, I mean save all zeroes incorrectly, leading to explosions if you restore it. Since we're not using AMX for anything, the simple way to avoid this is to just not save/restore those when we do anything, since we're killing preemption of any sort across our save/restores. If we ever decide to use AMX, it's not clear that we have any way to mitigate this, on Linux...but I am not an expert. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Rich Ercolani <rincebrain@gmail.com> Closes #14989 Closes #15168		2023-08-26 11:25:46 -07:00
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freebsd	FreeBSD: catch up to __FreeBSD_version 1400093	2023-07-13 09:06:57 -07:00
linux	Avoid save/restoring AMX registers to avoid a SPR erratum	2023-08-26 11:25:46 -07:00