Re: kvm_intel fails to load on Conroe CPUs running Linux 4.12

[Sebastian Rachuj]

On 07.08.2017 11:43, Paolo Bonzini wrote:
> On 06/08/2017 23:23, Sebastian Rachuj wrote:
> > On 06.08.2017 23:10, Paolo Bonzini wrote:
> > > On 05/08/2017 21:26, Sebastian Rachuj wrote:
> > > > Dear linux developers,
> > > >
> > > > since my upgrade from linux 4.11 to linux 4.12 the "kvm_intel" module
> > > > does not load correctly anymore. "Modprobing" the kernel module gives an
> > > > Input/Output error. It seems to be related to the CPU architecture and
> > > > (to my knowledge) affects Conroe CPUs. I did a bisect and found the
> > > > following commit as the guilty one:
> > >
> > > What is your cpuinfo?  I tested on a Conroe Xeon X3220 (family 6,
> > > model 15, stepping 11) when I posted that patch, and it did have virtual
> > > NMIs.
> >
> > Thank you for looking into the issue. My cpuinfo is as follows:
>
> Looks like Intel was already differentiating virtualization features
> across SKUs.  Please run the attached script as root to see what other
> things are different (apparently) between non-Xeon and Xeon Conroes.

Here you are, I hope it helps:

# python vmxcap
Basic VMX Information
  Hex: 0x1a040000000007
  Revision                                 7
  VMCS size                                1024
  VMCS restricted to 32 bit addresses      no
  Dual-monitor support                     yes
  VMCS memory type                         6
  INS/OUTS instruction information         no
  IA32_VMX_TRUE_*_CTLS support             no
pin-based controls
  External interrupt exiting               yes
  NMI exiting                              yes
  Virtual NMIs                             no
  Activate VMX-preemption timer            no
  Process posted interrupts                no
primary processor-based controls
  Interrupt window exiting                 yes
  Use TSC offsetting                       yes
  HLT exiting                              yes
  INVLPG exiting                           yes
  MWAIT exiting                            yes
  RDPMC exiting                            yes
  RDTSC exiting                            yes
  CR3-load exiting                         forced
  CR3-store exiting                        forced
  CR8-load exiting                         yes
  CR8-store exiting                        yes
  Use TPR shadow                           yes
  NMI-window exiting                       no
  MOV-DR exiting                           yes
  Unconditional I/O exiting                yes
  Use I/O bitmaps                          yes
  Monitor trap flag                        no
  Use MSR bitmaps                          yes
  MONITOR exiting                          yes
  PAUSE exiting                            yes
  Activate secondary control               no
secondary processor-based controls
  Virtualize APIC accesses                 no
  Enable EPT                               no
  Descriptor-table exiting                 no
  Enable RDTSCP                            no
  Virtualize x2APIC mode                   no
  Enable VPID                              no
  WBINVD exiting                           no
  Unrestricted guest                       no
  APIC register emulation                  no
  Virtual interrupt delivery               no
  PAUSE-loop exiting                       no
  RDRAND exiting                           no
  Enable INVPCID                           no
  Enable VM functions                      no
  VMCS shadowing                           no
  Enable ENCLS exiting                     no
  RDSEED exiting                           no
  Enable PML                               no
  EPT-violation #VE                        no
  Conceal non-root operation from PT       no
  Enable XSAVES/XRSTORS                    no
  Mode-based execute control (XS/XU)       no
  TSC scaling                              no
VM-Exit controls
  Save debug controls                      forced
  Host address-space size                  yes
  Load IA32_PERF_GLOBAL_CTRL               no
  Acknowledge interrupt on exit            yes
  Save IA32_PAT                            no
  Load IA32_PAT                            no
  Save IA32_EFER                           no
  Load IA32_EFER                           no
  Save VMX-preemption timer value          no
  Clear IA32_BNDCFGS                       no
  Conceal VM exits from PT                 no
VM-Entry controls
  Load debug controls                      forced
  IA-32e mode guest                        yes
  Entry to SMM                             yes
  Deactivate dual-monitor treatment        yes
  Load IA32_PERF_GLOBAL_CTRL               no
  Load IA32_PAT                            no
  Load IA32_EFER                           no
  Load IA32_BNDCFGS                        no
  Conceal VM entries from PT               no
Miscellaneous data
  Hex: 0x403c0
  VMX-preemption timer scale (log2)        0
  Store EFER.LMA into IA-32e mode guest control no
  HLT activity state                       yes
  Shutdown activity state                  yes
  Wait-for-SIPI activity state             yes
  IA32_SMBASE support                      no
  Number of CR3-target values              4
  MSR-load/store count recommendation      0
  IA32_SMM_MONITOR_CTL[2] can be set to 1  no
  VMWRITE to VM-exit information fields    no
  Inject event with insn length=0          no
  MSEG revision identifier                 0
VPID and EPT capabilities
  Hex: 0x0
  Execute-only EPT translations            no
  Page-walk length 4                       no
  Paging-structure memory type UC          no
  Paging-structure memory type WB          no
  2MB EPT pages                            no
  1GB EPT pages                            no
  INVEPT supported                         no
  EPT accessed and dirty flags             no
  Single-context INVEPT                    no
  All-context INVEPT                       no
  INVVPID supported                        no
  Individual-address INVVPID               no
  Single-context INVVPID                   no
  All-context INVVPID                      no
  Single-context-retaining-globals INVVPID no
VM Functions
  Hex: 0x0
  EPTP Switching                           no