Why is having an error initializing AMD-Vi?

Question

I have a Ryzen 5 1600x CPU with a MSI X370 Gaming Pro Carbon motherboard, which 100% supports I/O virtualization. When I boot in Ubuntu without Xen I can see:

me:~$ dmesg | grep IOMMU
[    1.074675] AMD-Vi: IOMMU performance counters supported
[    1.076696] AMD-Vi: Found IOMMU at 0000:00:00.2 cap 0x40
[    1.078029] perf/amd_iommu: Detected AMD IOMMU #0 (2 banks, 4 counters/bank).
[    1.352681] AMD IOMMUv2 driver by Joerg Roedel <[email protected]>
me:~$ dmesg | grep AMD-V
[    1.074675] AMD-Vi: IOMMU performance counters supported
[    1.076696] AMD-Vi: Found IOMMU at 0000:00:00.2 cap 0x40
[    1.076697] AMD-Vi: Extended features (0xf77ef22294ada):
[    1.076699] AMD-Vi: Interrupt remapping enabled
[    1.076700] AMD-Vi: virtual APIC enabled
[    1.076801] AMD-Vi: Lazy IO/TLB flushing enabled

However, when I boot into Xen I see

.....
(XEN) Detected 3600.165 MHz processor.
(XEN) Initing memory sharing.
(XEN) AMD-Vi: Error initialization
(XEN) I/O virtualisation disabled
(XEN) ENABLING IO-APIC IRQs
(XEN)  -> Using new ACK method
(XEN) Platform timer is 14.318MHz HPET
(XEN) Allocated console ring of 32 KiB.
(XEN) HVM: ASIDs enabled.
(XEN) SVM: Supported advanced features:
(XEN)  - Nested Page Tables (NPT)
(XEN)  - Last Branch Record (LBR) Virtualisation
(XEN)  - Next-RIP Saved on #VMEXIT
(XEN)  - VMCB Clean Bits
(XEN)  - DecodeAssists
(XEN)  - Pause-Intercept Filter
(XEN)  - TSC Rate MSR
(XEN) HVM: SVM enabled
(XEN) HVM: Hardware Assisted Paging (HAP) detected
(XEN) HVM: HAP page sizes: 4kB, 2MB, 1GB
(XEN) Brought up 12 CPUs
.....

Does anyone have any suggestions on even where to look for why Xen isn't loading AMD-Vi?

Answer 1

Sorry guys for my previous inappropriate post. So I have had the same situation, my specs: CPU AMD FX8350, mobo Asus 970 Pro Gaming/Aura. I have done: BIOS settings -> CPU configuration -> SVM enabled

When I tried "lscpu" in Ubuntu:

Virtualization: AMD-v

But when I tried "lscpu" in Xen Hypervisor:

Virtualization: None

Turned out this is completely normal:

NOTE that Linux dom0 kernel doesn't see 'vmx' or 'svm' CPU flags in "/proc/cpuinfo" because Xen hypervisor (xen.gz) is using the hardware virtualization features and hiding the flags from dom0! Xen dom0 is actually a virtual machine, so it doesn't see all the cpu flags as Xen hypervisor is hiding some flags from dom0.

Source:https://wiki.xenproject.org/wiki/Xen_Common_Problems

What you should pay attention to when boot into Xen Hypervisor is this command: "xl dmesg"

If it returns "SVM enabled" and "IOMMU enabled" your machine fully support virtualization.

If you're missing any of them, please boot into BIOS settings:

For SVM: Advanced -> CPU Configuration -> SVM enable.

For IOMMU: Advanced -> Northbridge Configuation -> IOMMU enable.

I think Intel CPU is similar. Good luck!!