How can I change the CC mode of H100 NVL in NCC40ads H100 v5 VM?

Question

How can I change the CC mode of H100 NVL in NCC40ads H100 v5 VM?

Sungkun Moon 20

Hi,

I have created an instance of VM the type of which is NCC40ads H100 v5.

I want to change the CC mode of H100 to "CC-off" by using the nvidia's tool as below.

(dev) furiosa@confidential-vm:~/gpu-admin-tools$ sudo python3 ./nvidia_gpu_tools.py --gpu-bdf 00:00.0 --query-cc-mode NVIDIA GPU Tools version v2025.04.07o ... self.dev.write(self.offset, self.value.raw, self.size) File "/home/furiosa/gpu-admin-tools/utils/file_raw.py", line 41, in write os.write(self.fd, data_from_int(data, size)) 2025-04-14,07:47:36.514 ERROR Device /sys/bus/pci/devices/0001:00:00.0 broken [Errno 1] Operation not permitted

But it failed.

How can I change the mode of the H100 attached in this VM?

Currently the mode is set as "CC-On".

If it is not possible, can you share the type of VM where H100 NVL and AMD Epyc 4th process is used but CC mode is turned off?

Dharani Reguri 345 Reputation points Microsoft External Staff

2025-04-14T17:43:26.0466667+00:00

Hi Sungkun Moon,

I understood that you are trying to change the CC mode of the VM, but the operation was failed. On the same, I'm checking with the internal team to get more information on it and will get back to you as soon as I have an update.

Thank you.
Dharani Reguri 345 Reputation points Microsoft External Staff

2025-04-15T09:33:41.7833333+00:00
Hi Sungkun Moon,

Thanks for your patience.

I have checked with my product team, and they confirmed that Confidential computing mode is already off at the VM SKU NCads H100 v5 VM and no further action is needed.

The command which you have tried is at Azure host level (cluster level) command and can't be used at Guest VM level. Hence the "Operation has failed". In order to verify the confidential computing (CC) mode at the Guest VM level during NVIDIA driver installation, you can use the following command within the VM:

nvidia-smi conf-compute -f

Please may I know how you have identified that CC mode is turned on for the VM?

Please let me know if you have any questions.

Thank you.
Sungkun Moon 20 Reputation points

2025-04-16T02:16:36.0966667+00:00

Hi Dharani,

Sorry for misinformation. I am currently using NCC40ads H100 v5 VM.

In this type of VM, I could identify the mode of H100 as below:

$ nvidia-smi conf-compute -f

CC status: ON

If the CC mode cannot be changed, should I use NCads H100 v5 type to use non-TEE version?

Thank you.

Accepted answer

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Dharani Reguri 345 Reputation points Microsoft External Staff

2025-04-14T17:43:26.0466667+00:00

Hi Sungkun Moon,

I understood that you are trying to change the CC mode of the VM, but the operation was failed. On the same, I'm checking with the internal team to get more information on it and will get back to you as soon as I have an update.

Thank you.
Dharani Reguri 345 Reputation points Microsoft External Staff

2025-04-15T09:33:41.7833333+00:00

Hi Sungkun Moon,

Thanks for your patience.

I have checked with my product team, and they confirmed that Confidential computing mode is already off at the VM SKU NCads H100 v5 VM and no further action is needed.

The command which you have tried is at Azure host level (cluster level) command and can't be used at Guest VM level. Hence the "Operation has failed". In order to verify the confidential computing (CC) mode at the Guest VM level during NVIDIA driver installation, you can use the following command within the VM:

nvidia-smi conf-compute -f

Please may I know how you have identified that CC mode is turned on for the VM?

Please let me know if you have any questions.

Thank you.
Sungkun Moon 20 Reputation points

2025-04-16T02:16:36.0966667+00:00

Hi Dharani,

Sorry for misinformation. I am currently using NCC40ads H100 v5 VM.

In this type of VM, I could identify the mode of H100 as below:

$ nvidia-smi conf-compute -f

CC status: ON

If the CC mode cannot be changed, should I use NCads H100 v5 type to use non-TEE version?

Thank you.

Answer 1

Dharani Reguri 345 Microsoft External Staff

Hi Sungkun Moon,

As said, CC mode can only be switched (ON/OFF) at the host (cluster) level, you can't switch the mode at guest VM level.

If you would like to use CC mode OFF, then you can use NC40ads H100 v5 VM which is an equivalent non-CC version.

If it was helpful, please click "Upvote" on this post and "Accept" the answer for the benefit of community.

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Answer 2

Sungkun Moon 20

Thank you for your answer.

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How can I change the CC mode of H100 NVL in NCC40ads H100 v5 VM?

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