zfs/include/os/linux
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
..
kernel/linux Avoid save/restoring AMX registers to avoid a SPR erratum 2023-08-26 11:25:46 -07:00
spl linux/spl/kmem_cache: undefine `kmem_cache_alloc` before defining it 2023-08-07 13:55:59 -07:00
zfs/sys linux: implement filesystem-side copy/clone functions for EL7 2023-07-24 16:37:04 -07:00
Makefile.am Add SHA2 SIMD feature tests for Linux 2023-03-02 13:52:04 -08:00