Bug while creating the first i/o completion queue (NVMe over PCIe)

[osdev199]

Hi, in my nvme driver, while creating the first i/o completion queue, it is failing with the status code 2 (Invalid Field in Command). I have double checked my commands and still can't figure out which cmd is invalid.

Here are my commands: https://pastebin.com/PYiL0WJA . I'm testing my driver on my real machine.

[Octocontrabass]

it is failing with the status code 2

What's the status code type?

[osdev199]

status code type is 1 (Command Specific Status).

[Octocontrabass]

When the status code type is 1, status code 2 means "Maximum Queue Size Exceeded". Use CAP.MQES to choose a valid queue size.

[osdev199]

Thank you. Before creating the i/o completion queue, I was reading the CAP register value. Accidentally I was doing `*addr = value` instead of `value = *addr`. I fixed this and I checked that the queue size i.e. 64 commands is valid. Still I'm getting the same error status.

[Octocontrabass]

What is the value of the CAP register?

Have you tried your driver in a virtual machine like QEMU?

[osdev199]

CAP register value = 0x300a0103ff

I have tried running it on qemu too but launching qemu fails with "gtk initialization failed". I haven't been able to solve this issue yet!

[Octocontrabass]

How are you launching QEMU? How did you install QEMU?

[osdev199]

Code: Select all

$ qemu-system-x86_64 -M q35 -smbios type=0,uefi=on -bios /usr/share/ovmf/OVMF.fd -enable-kvm -cpu host -drive format=raw,file=disk.img,if=none,id=NVME1 -device nvme,drive=NVME1,serial=nvme-1 -trace pci_nvme*

I don't remember how did I install it. But as far as I know, when I added a password to my user account recently, this error began to appear. I'm already using `export DISPLAY=:0` in my .bashrc.

[osdev199]

After asking on #qemu irc channel, I changed the DISPLAY value to 1 and it worked. Now in qemu, while resetting the controller during initialization, on clearing the CC.EN (bit #0) to 0, and writing it back, the new CC register value becomes 0 don't know why. However, the driver halts a bit later on the fatal error: CSTS.CFS is not 0!

I'm pasting the screenshot: https://drive.google.com/file/d/1Ay_8w7 ... sp=sharing

[Octocontrabass]

You need to choose reasonable values for CC.IOSQES and CC.IOCQES.

[mleks]

Please take a look at my code on this matter: https://github.com/MaciekLeks/bebok/blo ... e.zig#L905 . I have resolved the issue with sc=0x02 for sct=0x01. Now I'm struggling with sc=0x08. Good luck!

[osdev199]

I don't like the virtual machine.

The others drivers I have checked have the same commands as mine and they are working fine.

If so, then why am I getting the error?

[osdev199]

You can also resume the discussion in the issue that I have opened in the project:

https://github.com/robstat7/Raam/issues/4

[Octocontrabass]

sc=0x08

Invalid Interrupt Vector. You're using pin-based interrutps, so the interrupt vector needs to be 0. If you switch to MSI or MSI-X, the interrupt vector is the index in the list of MSI(-X) interrupts you've configured on the NVMe controller. The interrupt vector you need to use here is not the same as a CPU interrupt vector.

I don't like the virtual machine.

Does your code work in the virtual machine?