mirror_zfs/include/os/linux/kernel/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
..
blkdev_compat.h Linux 6.5 compat: blkdev changes 2023-08-01 08:37:20 -07:00
compiler_compat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dcache_compat.h Workaround for Linux PowerPC GPL-only cpu_has_feature() 2023-03-10 09:35:00 -08:00
kmap_compat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
mod_compat.h Finally drop long disabled vdev cache. 2023-06-09 12:40:55 -07:00
page_compat.h Linux 5.9 compat: NR_SLAB_RECLAIMABLE 2020-08-29 20:57:45 -07:00
percpu_compat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
simd_aarch64.h Add SHA2 SIMD feature tests for Linux 2023-03-02 13:52:04 -08:00
simd_arm.h Add SHA2 SIMD feature tests for Linux 2023-03-02 13:52:04 -08:00
simd_powerpc.h Refactor CONFIG_SPE check on Linux/powerpc 2023-03-15 10:30:42 -07:00
simd_x86.h Avoid save/restoring AMX registers to avoid a SPR erratum 2023-08-26 11:25:46 -07:00
simd.h Add SHA2 SIMD feature tests for Linux 2023-03-02 13:52:04 -08:00
utsname_compat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vfs_compat.h Linux 6.3 compat: idmapped mount API changes 2023-04-10 14:15:36 -07:00
xattr_compat.h Linux 6.3 compat: idmapped mount API changes 2023-04-10 14:15:36 -07:00