x86/cpu: Fix AMD erratum #1485 on Zen4-based CPUs

stable inclusion
from stable-v4.19.297
commit 05868a16aab502d48a05a9528f23002fbf830335
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8MCB5
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.19.y&id=05868a16aab5



---------------------------

commit f454b18e upstream.

Fix erratum #1485 on Zen4 parts where running with STIBP disabled can
cause an #UD exception. The performance impact of the fix is negligible.

Reported-by: René Rebe <rene@exactcode.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: René Rebe <rene@exactcode.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/D99589F4-BC5D-430B-87B2-72C20370CF57@exactcode.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
	arch/x86/kernel/cpu/amd.c
Signed-off-by: liwei <liwei728@huawei.com>