Mailing List Archive

VT-x turned off and on
Discovered that VT-b was turned off in my server's BIOS.   After turning
it on, I get these results from xl dmesg:

(XEN) Intel VT-d iommu 0 supported page sizes: 4kB
(XEN) Intel VT-d Snoop Control enabled.
(XEN) Intel VT-d Dom0 DMA Passthrough not enabled.
(XEN) Intel VT-d Queued Invalidation enabled.
(XEN) Intel VT-d Interrupt Remapping enabled.
(XEN) Intel VT-d Posted Interrupt not enabled.
(XEN) Intel VT-d Shared EPT tables not enabled.
(XEN) I/O virtualisation enabled
(XEN)  - Dom0 mode: Relaxed
(XEN) Interrupt remapping enabled


That shows me that it is turned on and working, but if I do a

#egrep -c '(vmx|svm)' /proc/cpuinfo

It doesn't find anything (0)
Re: VT-x turned off and on [ In reply to ]
Hello,

On 31/08/2021 00:42, TheBearAK wrote:
> Discovered that VT-b was turned off in my server's BIOS.   After turning
> it on, I get these results from xl dmesg:
>
> (XEN) Intel VT-d iommu 0 supported page sizes: 4kB
> (XEN) Intel VT-d Snoop Control enabled.
> (XEN) Intel VT-d Dom0 DMA Passthrough not enabled.
> (XEN) Intel VT-d Queued Invalidation enabled.
> (XEN) Intel VT-d Interrupt Remapping enabled.
> (XEN) Intel VT-d Posted Interrupt not enabled.
> (XEN) Intel VT-d Shared EPT tables not enabled.
> (XEN) I/O virtualisation enabled
> (XEN)  - Dom0 mode: Relaxed
> (XEN) Interrupt remapping enabled
>
>
> That shows me that it is turned on and working, but if I do a
>
> #egrep -c '(vmx|svm)' /proc/cpuinfo
>
> It doesn't find anything (0)

This is expected because /proc/cpuinfo shows the features exposed to
dom0 and Xen will hide VMX/SVM.

If you boot on directly Linux, you should be able to find VMX/SVM from
/proc/cpuinfo.

Best regards,

--
Julien Grall