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

[Anand J]

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
0x00000000000eecc4:  push   %ebx
0x00000000000eecc5:  xor    %ecx,%ecx
0x00000000000eecc7:  mov    (%eax,%ecx,1),%bl
0x00000000000eecca:  cmp    (%edx,%ecx,1),%bl
0x00000000000eeccd:  je     0xeecdc

vmexit(0000004e, 0000000000000000, 00000000000f5ea0, 00000000000eecc4)!
CR2: 0000000000000000
vmsave! 00000000b8592000
FS: 0000000000000000 | 0000000000000000
vmload! 00000000b8592000
FS: 0000000000000000 | 0000000000000000
vmrun! 00000000b8592000
CR3: 00000000b86bd000    CR2: 0000000000000000
----------------
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?

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
>
>