AES NI vs BIOS settings

Kostik Belousov kostikbel at
Mon May 31 08:35:17 UTC 2010

On Sun, May 30, 2010 at 10:55:39PM -0700, Xin LI wrote:
> Hash: SHA256
> Hi,
> I just found that if I disable "AES NI" in BIOS setting, FreeBSD would
> be able to detect it on boot with:
> However if it's set to "enabled" I got:
> Features2=0x9ee3fd<SSE3,DTES64,MON,DS_CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,<b17>,DCA,SSE4.1,SSE4.2,POPCNT>
> The CPU was Xeon L5630 and motherboard is Supermicro X8STi with BIOS
> 1.00c.  Should I consider this a BIOS issue with known workaround that I
> consider "Disable" as "Enabled"? :)

On the only machine with AESNI-capable Core i5 I have access to thanks
to Sentex Communications, AESNI bit is reported as 1 and aesni instructions
do work.

You could try to actually use aesni and see what is broken. I failed to
find a magic bit to enable/disable AESNI in the MSRs.
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