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CPU flags not passing through into container (SSE 4.2)

Hi,

I’m running the M1 tech preview of Docker on my macbook pro.
On the host machine, if I run the following:
sysctl -a | grep machdep.cpu.features
I get the following result:
“machdep.cpu.features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 PCLMULQDQ DTSE64 MON DSCPL VMX EST TM2 SSSE3 CX16 TPR PDCM SSE4.1 SSE4.2 AES SEGLIM64”
(notably, it includes SSE4.2 - which I require for a program I need to run within the container).

I have then pulled an image, and when I run the container derived from it (starting an interactive shell),
I then run the following: cat /proc/cpuinfo
and get the following output:
processor : 0
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm jscvt fcma lrcpc dcpop sha3 asimddp sha512 asimdfhm dit uscat ilrcpc flagm ssbs
CPU implementer : 0x00
CPU architecture: 8
CPU variant : 0x0
CPU part : 0x000
CPU revision : 0

processor : 1
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm jscvt fcma lrcpc dcpop sha3 asimddp sha512 asimdfhm dit uscat ilrcpc flagm ssbs
CPU implementer : 0x00
CPU architecture: 8
CPU variant : 0x0
CPU part : 0x000
CPU revision : 0

processor : 2
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm jscvt fcma lrcpc dcpop sha3 asimddp sha512 asimdfhm dit uscat ilrcpc flagm ssbs
CPU implementer : 0x00
CPU architecture: 8
CPU variant : 0x0
CPU part : 0x000
CPU revision : 0

processor : 3
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm jscvt fcma lrcpc dcpop sha3 asimddp sha512 asimdfhm dit uscat ilrcpc flagm ssbs
CPU implementer : 0x00
CPU architecture: 8
CPU variant : 0x0
CPU part : 0x000
CPU revision : 0

Which doesn’t include SSE4.2. Why is SSE4.2 not available? It seems to be available on the host machine.
Any advice would be much appreciated.

Thanks!