Receiving "iopl: Operation not permitted"/"You need to be root" error about intelmetool

[cbarcenas]

I got this error too, and tracked the issue down.

iopl() returns an error EPERM (Operation not permitted) - even when invoked as root - if the kernel is in "lockdown mode". One of the things that lockdown mode does is disables userspace access to privileged I/O.

You can check if you are in lockdown mode as follows:

$ cat /sys/kernel/security/lockdown 
none [integrity] confidentiality

Modern Linux distributions - such as Debian, in my case - will automatically enter lockdown mode (integrity) when the kernel is booted with EFI Secure Boot enabled. To fix the issue I simply disabled Secure Boot and restarted my machine.

[zamaudio]

@eloydegen first of all, your change applies to inteltool not intelmetool. Second, this repository is retired. I am no longer maintaining it, it is there to preserve history. See coreboot/util for upstream. Thanks.

[eloydegen]

@zamaudio I see, my apologies!

[zamaudio]

No idea, I just tried on a system with 4.14.7-300.fc27.x86_64 and iomem=relaxed and it worked... Maybe Ubuntu has some special kernel patches applied that prevents pci i/o space from being mapped? Can you try running it again and then paste the output of dmesg | tail.

[zamaudio]

Maybe paste also cat /boot/config-$(uname -r) |grep DEVMEM

[troyready]

Nothing notable from dmesg (nothing added after running the intelmetool command; last entries are ALLOWED apparmor entries for chromium and wifi association)

for DEVMEM settings:

root@mysystem:/home/myuser/intelmetool# cat /boot/config-$(uname -r) |grep DEVMEM
CONFIG_DEVMEM=y
CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y
CONFIG_STRICT_DEVMEM=y
# CONFIG_IO_STRICT_DEVMEM is not set

[zamaudio]

You can try the mekernel branch of intelmetool instead. I just updated it so you can build the kernel module and insert it, and then check dmesg for its output.

[eloydegen]

Issue is fixed with this commit: https://review.coreboot.org/c/coreboot/+/63702

@zamaudio can you close this issue?