Re: [Qemu-devel] facing issue with qemu amd-v support

[Paolo Bonzini]

On 14/11/2016 11:08, Anand J wrote:
> Hi,
> 
> Further investigation to the issue revealed that this happens before the
> guest OS get to execute. KVM is not able to emulate a PF happened during a
> jump to 0x40000000.
> 
> Folowing is the trace of instructions at which the emulation error is
> happening.
> 
> ----------------
> IN:
>  CR3: 00000000b8590000
>  CR2: 0000000000000000
> 0x00000000000eeccf:  setl   %al
> 0x00000000000eecd2:  movzbl %al,%eax
> 0x00000000000eecd5:  neg    %eax
> 0x00000000000eecd7:  or     $0x1,%eax
> 0x00000000000eecda:  jmp    0xeece3
> 
> ----------------
> IN:
>  CR3: 00000000b8590000
>  CR2: 0000000000000000
> 0x00000000000eece3:  pop    %ebx
> *0x00000000000eece4:  ret   *
> 
> vmexit(0000004e, 0000000000000000, 0000000040000000, 0000000040000000)!
> CR2: 0000000000000000
> vmsave! 00000000b8592000
> FS: 0000000000000000 | 0000000000000000
> ----------------
> 
> Bold ret instruction causes a VMEXIT due to page fault. Can anyone please
> help me figure out possible causes for this issue?

Sorry, I cannot really guess what's going on.  All I can suggest is to
look at KVM's trace normally and under QEMU, and find the difference.

Paolo

> Thanks,
> Anand
> 
> On Mon, Oct 24, 2016 at 2:35 PM, Anand J <address@hidden> wrote:
> 
>>
>> ---------- Forwarded message ----------
>> From: Anand J <address@hidden>
>> Date: Mon, Oct 24, 2016 at 4:28 AM
>> Subject: facing issue with qemu amd-v support
>> To: address@hidden
>>
>>
>> Hi,
>>
>> I'm running fedora-24_x86_64 inside qemu in software mode. I configured
>> KVM in the guest OS and want to run qemu inside the guest with kvm enabled.
>> But qemu is throwing the following error. Does anybody know how to fix this?
>>
>> KVM internal error. Suberror: 1
>> emulation failure
>> EAX=ffffffff EBX=4000004b ECX=00000000 EDX=000f5ea0
>> ESI=00000000 EDI=00000000 EBP=00000000 ESP=00006fd0
>> EIP=40000000 EFL=00000086 [--S--P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
>> ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
>> CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
>> SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
>> DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
>> FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
>> GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
>> LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
>> TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
>> GDT=     000f7180 00000037
>> IDT=     000f71be 00000000
>> CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
>> DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000
>> DR3=0000000000000000
>> DR6=00000000ffff0ff0 DR7=0000000000000400
>> EFER=0000000000000000
>> Code=00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00
>> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> 00 00 00
>>
>>
>> Thanks,
>> Anand
>>
>>
>