Trouble starting SEV, SEV-ES, SEV-SNP on EPYC 8024P

[SudNeela]

I have an AMD EPYC 8024P and I'm having issues starting SEV, SEV-ES, and SEV-SNP. I've enabled SEV-SNP in BIOS, set the ASIDs appropriately (256 out of 1006), and enabled SMEE.

However, I still don't have the /dev/sev interface. This is the output after modprobe ccp:

ccp 0000:02:00.5: sev enabled
ccp 0000:02:00.5: psp enabled
ccp 0000:02:00.5: SEV: failed to get status. Error: 0x8003

After modprobe kvm_amd:

kvm_amd: TSC scaling supported
kvm_amd: Nested Virtualization enabled
kvm_amd: Nested Paging enabled
kvm_amd: LBR virtualization supported
kvm_amd: SEV enabled (ASIDs 256 - 1006)
kvm_amd: SEV-ES enabled (ASIDs 1 - 255)
kvm_amd: SEV-SNP enabled (ASIDs 1 - 255)
kvm_amd: Virtual VMLOAD VMSAVE supported
kvm_amd: Virtual GIF supported
kvm_amd: Virtual NMI enabled

Which firmware should I be using from https://www.amd.com/en/developer/sev.html? Is there something else I could be possibly missing? Please let me know if you would like more information.

TIA.

[tlendacky]

What's the output of cpuid -1 -l 0x8000001f ?