I am playing with AMD Epyc nowadays and my motherboard is Supermicro H11DSU. There is a new technology called SEV-ES VM which is supposed by EPYC series. However, in order to enable that, I need to change something called SEV-ES ASID Space Limit in the BIOS, which indicate how many SEV-ES machines are supported running at the same time. According to the manual, the value 1 (defaulted
value) means no SEV-ES machine is supported and value 2 means 1 machine is supported, 3 means 2 machines ..... I have collected all public BIOS version but the menu in BIOS for changing the Space Limit are all hidden.

When I use IFR extractor to get some content of those BIOS, For most BIOS versions, after searching "ASID", I can only get something like

0xAB49 Numeric: SEV-ES ASID Space Limit (51539607680-51539607680) , Variable: 0x9 {07 9A 2C 00 2D 00 10 00 00 50 09 00 10 22 01 00 00 00 10 00 00 00 00 00 00 00}
0xAB63 Default: 32 Bit, Value: 0x5A {5B 09 00 00 02 01 00 00 00}
0xAB6C End {29 02}

OR besides this, I can find a setting in BIOS 2.0b:

0xACBB Setting: SEV-ES ASID Space Limit Control, Variable: 0x27 {05 91 27 00 28 00 12 00 00 50 27 00 10 10 00 01 00}
0xACCC Option: Auto, Value: 0x0 (default) {09 07 14 00 10 00 00}
0xACD3 Option: Manual, Value: 0x1 {09 07 29 00 00 00 01}
0xACDA End of Options {29 02}

I tried to enter a grub menu before booting and use setup_var to change the option from Auto 0x0 to Manual 0x1. But since the menu for the setting are hidden, I have no idea about how to change the numeric here.
I wonder whether someone have met problems like this before. Can I just use setup_var to change some variable directly in order to change the space limit instead of trying to show those hidden menu? Any advice is welcome. I am stuck here for several weeks now.

Thanks

try AMISCE to read and write NVAR values.