Hello,

A bit of Context (Can be Skipped): I bought this laptop to use Linux and Windows VM using PCI-passthrough for the GPU, the problem is that Lenovo Doesn't show IOMMU Option In the BIOS, so I cannot enable it.

The Bios is a InsydeH20, but it seem a different from the one I saw online, as it the one with the mouse support rubbish (
).

I tried all possible key combo to unlock Hidded Feuture, but accordind to the Murphy law this not Worked at all.
So after a bit of research I discovered H20UVE and H20EZE, but I'm a bit scared, that these are old compared to my bios and could brick my laptop.


Regarding the option that I want to enable, I found these with UEFITool/IRF Extractor, but I want a confirmation from one with more experience before
making damage.


The relevant Part of the IFR is from CbsSetupDxeRN Module:

0xAB6B 	Form: NBIO Common Options, FormId: 0x7004 {01 86 04 70 08 00}
0xAB71 		Subtitle: Statement.Prompt: NBIO Common Options, Flags: 0x0 {02 87 08 00 00 00 00}
0xAB78 		End {29 02}
0xAB7A 		Subtitle: Statement.Prompt: , Flags: 0x0 {02 87 02 00 00 00 00}
0xAB81 		End {29 02}
0xAB83 		One Of: IOMMU, VarStoreInfo (VarOffset/VarName): 0xCA, VarStore: 0x5000, QuestionId: 0xA6, Size: 1, Min: 0x0, Max 0xF, Step: 0x0 {05 91 39 02 3A 02 A6 00 00 50 CA 00 10 10 00 0F 00}
0xAB94 			One Of Option: Disabled, Value (8 bit): 0x0 {09 07 18 00 00 00 00}
0xAB9B 			One Of Option: Enabled, Value (8 bit): 0x1 {09 07 17 00 00 00 01}
0xABA2 			One Of Option: Auto, Value (8 bit): 0xF (default) {09 07 12 00 10 00 0F}
0xABA9 		End One Of {29 02}
0xABAB 		One Of: PCIe ARI Support, VarStoreInfo (VarOffset/VarName): 0xCB, VarStore: 0x5000, QuestionId: 0xA7, Size: 1, Min: 0x0, Max 0xF, Step: 0x0 {05 91 3B 02 3C 02 A7 00 00 50 CB 00 10 10 00 0F 00}
0xABBC 			One Of Option: Disabled, Value (8 bit): 0x0 {09 07 18 00 00 00 00}
0xABC3 			One Of Option: Enabled, Value (8 bit): 0x1 {09 07 17 00 00 00 01}
0xABCA 			One Of Option: Auto, Value (8 bit): 0xF (default) {09 07 12 00 10 00 0F}
0xABD1 		End One Of {29 02}
0xABD3 		One Of: PSPP Policy, VarStoreInfo (VarOffset/VarName): 0xCC, VarStore: 0x5000, QuestionId: 0xA8, Size: 1, Min: 0x0, Max 0xF, Step: 0x0 {05 91 3D 02 3E 02 A8 00 00 50 CC 00 10 10 00 0F 00}
0xABE4 			One Of Option: Disabled, Value (8 bit): 0x0 {09 07 18 00 00 00 00}
0xABEB 			One Of Option: Balanced, Value (8 bit): 0x2 {09 07 3F 02 00 00 02}
0xABF2 			One Of Option: Auto, Value (8 bit): 0xF (default) {09 07 12 00 10 00 0F}
0xABF9 		End One Of {29 02}
0xABFB 		Ref: GFX Configuration, VarStoreInfo (VarOffset/VarName): 0xFFFF, VarStore: 0x0, QuestionId: 0xA9, FormId: 0x7028 {0F 0F 40 02 40 02 A9 00 00 00 FF FF 00 28 70}
0xAC0A 		Suppress If {0A 82}
0xAC0C 			QuestionId: 0xAD equals value 0xF {12 86 AD 00 0F 00}
0xAC12 				Not {17 02}
0xAC14 				QuestionId: 0xAD equals value 0x1 {12 06 AD 00 01 00}
0xAC1A 				Not {17 02}
0xAC1C 				And {15 02}
0xAC1E 				QuestionId: 0xAD equals value 0x2 {12 06 AD 00 02 00}
0xAC24 				Not {17 02}
0xAC26 				And {15 02}
0xAC28 			End {29 02}
0xAC2A 			Ref: Audio Configuration, VarStoreInfo (VarOffset/VarName): 0xFFFF, VarStore: 0x0, QuestionId: 0xAA, FormId: 0x7029 {0F 0F 41 02 41 02 AA 00 00 00 FF FF 00 29 70}
0xAC39 		End If {29 02}
0xAC3B 		Ref: XFR Enhancement, VarStoreInfo (VarOffset/VarName): 0xFFFF, VarStore: 0x0, QuestionId: 0xAB, FormId: 0x702A {0F 0F 42 02 42 02 AB 00 00 00 FF FF 00 2A 70}
0xAC4A 		Ref: SMU Common Options, VarStoreInfo (VarOffset/VarName): 0xFFFF, VarStore: 0x0, QuestionId: 0xAC, FormId: 0x702B {0F 0F 43 02 43 02 AC 00 00 00 FF FF 00 2B 70}
0xAC59 		Suppress If {0A 82}
0xAC5B 			QuestionId: 0xA6 equals value 0x1 {12 86 A6 00 01 00}
0xAC61 				Not {17 02}
0xAC63 			End {29 02}
0xAC65 			One Of: DMAr Support, VarStoreInfo (VarOffset/VarName): 0xCD, VarStore: 0x5000, QuestionId: 0x702C, Size: 1, Min: 0x0, Max 0xF, Step: 0x0 {05 91 44 02 45 02 2C 70 00 50 CD 00 14 10 00 0F 00}
0xAC76 				One Of Option: Auto, Value (8 bit): 0xF (default) {09 07 12 00 10 00 0F}
0xAC7D 				One Of Option: Enabled, Value (8 bit): 0x1 {09 07 17 00 00 00 01}
0xAC84 				One Of Option: Disabled, Value (8 bit): 0x0 {09 07 18 00 00 00 00}
0xAC8B 			End One Of {29 02}
0xAC8D 		End If {29 02}
0xAC8F 	End Form {29 02}
 
 

So To enable IOMMU I have TO :

Resolved by myself

@AARCH64_EL3 - Yes, setup_var may work, or you may need to dump vars with CMD-line H2OUVE, edit, then flash back (Safest and best way)

For #4 - You may only be looking at CBS IFR, there is also setup module IFR which would have the rest of stuff from normal BIOS area such as the setting you asked about.

hello

I have the same issue for the same reason, how did you resolve it?

Hello @AARCH64_EL3, thanks for these pointers, I was able to enable IOMMU & DMAR following these steps:

1. Download modGRUBShell.efi from github(.)com/datasone/grub-mod-setup_var/releases (or compile from source) and place it in a bootable usb, assuming your device is /dev/sda:

sudo wipefs -a /dev/sda
sudo parted /dev/sda mktable msdos
sudo parted /dev/sda mkpart primary fat32 0% 100%
sudo mkfs.fat -F 32 /dev/sda1
sudo parted /dev/sda set 1 boot on

sudo mount /dev/sda1 /mnt
sudo mkdir -p /mnt/EFI/BOOT
sudo cp ./modGRUBShell.efi /mnt/EFI/BOOT/bootx64.efi

2. Boot from usb, and when at grub prompt, issue the following 2 commands:

setup_var_cv AmdSetup 0xCA 0x1 0x1
setup_var_cv AmdSetup 0xCD 0x1 0x1

Note: It's necessary to use setup_var_cv instead of setup_var since the variables are in a different varstore (0x5000 = AmdSetup) than the default

Now reboot, and both features will be enabled

hello im new here thanks for help i tried your guide on EUCN31WW and it worked msinfo32 says that kernel DMA protection is on
PROTIP on linux you can enable iommu=pt and intel/ amd_iommu=on on the ubuntu livecd by pressing e to edit the command line and put after /vmlinuz.efi

but will this still work for [LENOVO EUCN33WW 23/09/2021] BIOS
i reverted my bios to defaults and installed the newest firmware via lenovo vantage to avoid errors
after a few reboots i tried it again it says [GUID does not match expected GUID taking it nevertheless] this is the same output as last time when it worked
but this time it no longer seems to work strangely the mobilepassthorugh script says that IOMMU VT-D/AMD-Vi is enabled in the uefi but DMAR is off on msinfo32
did the lenovo developers patch this method? it says on the changelog the wakeup sleep issue was fixed surprisingly i never experienced any instability unlike what reddit said

also can i use this method with different variables to increase the radeon iGPU to 2gb VRAM flashing BIOSes is too dangerous for me even though my device is still in warranty
512mb of vram feels bare minimum edge would lag for a second when watching multiple youtube tabs simultaneously and i can notice it going to peak 480mb on task manager