How to enable AVX in a UEFI application?

[poby]

I have a simple working UEFI application except avx instructions don't work. Host supports AVX and I'm using the latest version of virtualbox which supports avx and the following works (doesn't hang)

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movdqa    xmm0, dqword[testmem]

testmem is defined elsewhere as

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align 32
testmem:   rb   128

However the following causes the program to hang up, and not proceed.

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vmovdqa    ymm0, qqword[testmem]

I have tried enabling AVX with

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mov     rcx, 0
xgetbv
or      rax, 0007h
xsetbv 

But it doesn't help.

What am I missing?

[BrightLight]

I enable AVX this way.

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	; enable AVX
	mov rax, cr4
	or eax, 0x40000
	mov cr4, rax

	mov rcx, 0
	xgetbv

	or eax, 6
	mov rcx, 0
	xsetbv

[poby]

I enable AVX this way.

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	; enable AVX
	mov rax, cr4
	or eax, 0x40000
	mov cr4, rax

	mov rcx, 0
	xgetbv

	or eax, 6
	mov rcx, 0
	xsetbv

THANK YOU SOOOO MUCH!!! I've spent hours googling and reading intel manuals etc and your code just works! Awesome man!