[Qemu-devel] [Bug 1541643] [NEW] IA32_FEATURE_CONTROL MSR unset for nested virtualization

[Stephen Crane]

Public bug reported:

I enabled nested virtualization for the kvm_intel module, and passed
-enable-kvm and -cpu host to qemu. However, the qemu BIOS did not set
IA32_FEATURE_CONTROL MSR (index 0x3a) to a non-zero value allow VMXON.
According to the Intel manual Section 23.7 ENABLING AND ENTERING VMX
OPERATION: "To enable VMX support in a platform, BIOS must set bit 1,
bit 2, or both (see below), as well as the lock bit."

I noticed an old mailing list thread on this
(https://lists.nongnu.org/archive/html/qemu-
devel/2015-01/msg01372.html), but I wanted to point out that the Intel
manual (and all the physical hardware I've tested) specifically
contradicts this response.

Tested on kernel 4.3.3 and qemu 2.4.1.

** Affects: qemu
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1541643

Title:
  IA32_FEATURE_CONTROL MSR unset for nested virtualization

Status in QEMU:
  New

Bug description:
  I enabled nested virtualization for the kvm_intel module, and passed
  -enable-kvm and -cpu host to qemu. However, the qemu BIOS did not set
  IA32_FEATURE_CONTROL MSR (index 0x3a) to a non-zero value allow VMXON.
  According to the Intel manual Section 23.7 ENABLING AND ENTERING VMX
  OPERATION: "To enable VMX support in a platform, BIOS must set bit 1,
  bit 2, or both (see below), as well as the lock bit."

  I noticed an old mailing list thread on this
  (https://lists.nongnu.org/archive/html/qemu-
  devel/2015-01/msg01372.html), but I wanted to point out that the Intel
  manual (and all the physical hardware I've tested) specifically
  contradicts this response.

  Tested on kernel 4.3.3 and qemu 2.4.1.

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