On 22/04/2009 15:04, "Tom Rotenberg" <
tom.rotenberg@xxxxxxxxx> wrote:
> Keir,
> Just to make sure, i am using the following patch, in order to disable the
> vm86 acceleration:
>
> diff -r cdc044f665dc xen/arch/x86/hvm/vmx/vmx.c
> --- a/xen/arch/x86/hvm/vmx/vmx.c Wed Apr 22 11:26:37 2009 +0100
> +++ b/xen/arch/x86/hvm/vmx/vmx.c Wed Apr 22 17:03:20 2009 +0300
> @@ -829,7 +829,7 @@
>
> if ( seg == x86_seg_tr )
> {
> - if ( v->domain->arch.hvm_domain.params[HVM_PARAM_VM86_TSS] )
> + if (0)
> {
> sel = 0;
> attr = vm86_tr_attr;
>
> Is this OK?
>
> Tom
>
> 2009/4/22 Keir Fraser <
keir.fraser@xxxxxxxxxxxxx>
>> Yes, the safest way to be sure is probably to replace the if() statement in
>> vmx_set_segment_register() that tests HVM_PARAM_VM86_TSS with if(0). That is
>> the only place in Xen that checks HVM_PARAM_VM86_TSS. Then you can
>> re-build/install Xen and be sure that vm86 accel must be disabled.
>>
>> -- Keir
>>
>> On 22/04/2009 14:52, "Tom Rotenberg" <
tom.rotenberg@xxxxxxxxx> wrote:
>>
>>> So, do u suggest, that i will set HVM_PARAM_VM86_TSS to 0, and re-check it?
>>>
>>> 2009/4/22 Tim Deegan <
Tim.Deegan@xxxxxxxxxx>
>>>> At 14:34 +0100 on 22 Apr (1240410866), Keir Fraser wrote:
>>>>> It could be an issue with the vm86 acceleration, possibly. I'm pretty sure
>>>>> the guest would have to IRET from protected mode to enter vm86 mode
>>>>> itself,
>>>>> and we don't emulate that. Tim: what would we need to do to disable the
>>>>> vm86
>>>>> acceleration for testing purposes? You suggested not setting VM86_TSS
>>>>> param
>>>>> from hvmloader, but I couldn't convince myself what effect that would
>>>>> actually have as the logic in Xen is non-trivial.
>>>>
>>>> Yes; if HVM_PARAM_VM86_TSS is zero, vmx_set_segment_register() will
>>>> always set the tss bit in the bitmap of segments that aren't safe to
>>>> enter VM86 with.
>>>>
>>>> Tim.
>>>>
>>>>>
>>>>> -- Keir
>>>>>
>>>>> On 22/04/2009 14:23, "Tom Rotenberg" <
tom.rotenberg@xxxxxxxxx> wrote:
>>>>>
>>>>>> Tim,
>>>>>>
>>>>>> so what does it mean? could it be that we have a bug in the real mode
>>>>>> emulation, which causes the segment state to be invalid (maybe it's
>>>>>> because
>>>>>> of
>>>>>> a bug in the patch that Keir made for me, which emulated the LLDT, and
>>>>>> the
>>>>>> LTR
>>>>>> instructions)?
>>>>>>
>>>>>> Keir suggested to trace back where the problem (segment state) occured,
>>>>>> and
>>>>>> from there to try and find the bug which caused it. Do u have any better
>>>>>> suggestion for solving this?
>>>>>>
>>>>>> Tom
>>>>>>
>>>>>> 2009/4/22 Tim Deegan <
Tim.Deegan@xxxxxxxxxx>
>>>>>>> At 13:39 +0100 on 22 Apr (1240407546), Tom Rotenberg wrote:
>>>>>>>> Keir,
>>>>>>>>
>>>>>>>> I have tried your latest patch, and it looks like now it passes the
>>>>>>>> emulation problem. However, now the domain crashes with the following
>>>>>>>> error:
>>>>>>>>
>>>>>>>> (XEN) HVM1: Booting from 0000:7c00
>>>>>>>> (XEN) Failed vm entry (exit reason 0x80000021) caused by invalid guest
>>>>>>>> state
>>>>>>>> (0).
>>>>>>>> (XEN) ************* VMCS Area **************
>>>>>>>> (XEN) *** Guest State ***
>>>>>>>> (XEN) CR0: actual=0x0000000080010039, shadow=0x0000000080000019,
>>>>>>>> gh_mask=ffffffffffffffff
>>>>>>>> (XEN) CR4: actual=0x0000000000002060, shadow=0x0000000000000000,
>>>>>>>> gh_mask=ffffffffffffffff
>>>>>>>> (XEN) CR3: actual=0x000000000a213a20, target_count=0
>>>>>>>> (XEN) target0=0000000000000000, target1=0000000000000000
>>>>>>>> (XEN) target2=0000000000000000, target3=0000000000000000
>>>>>>>> (XEN) RSP = 0x0000000000000080 (0x0000000000000080) RIP =
>>>>>>>> 0x000000000000002a (0x000000000000002a)
>>>>>>>> (XEN) RFLAGS=0x0000000000023202 (0x0000000000023202) DR7 =
>>>>>>>> 0x0000000000000400
>>>>>>>
>>>>>>> Looks like we're trying to VMENTER in virtual 8086 mode but without
>>>>>>> tidying up the segment state. That could either be the guest entering
>>>>>>> virtual 8086 mode itself or Xen entering vitrual 8086 mode to emulate
>>>>>>> real mode, but Xen is always careful to make the segment state agree
>>>>>>> with Intel's rather strict requrements when it does that.
>>>>>>>
>>>>>>> Tim.
>>>>>>>
>>>>>>>
>>>>>>>> (XEN) Sysenter RSP=0000000000000000 CS:RIP=0000:0000000000000000
>>>>>>>> (XEN) CS: sel=0x0060, attr=0x0c09b, limit=0xffffffff,
>>>>>>>> base=0x0000000000200000
>>>>>>>> (XEN) DS: sel=0x0068, attr=0x0c093, limit=0xffffffff,
>>>>>>>> base=0x0000000000200000
>>>>>>>> (XEN) SS: sel=0x0070, attr=0x0c093, limit=0xfc000fff,
>>>>>>>> base=0x000000000020ba62
>>>>>>>> (XEN) ES: sel=0x0068, attr=0x0c093, limit=0xffffffff,
>>>>>>>> base=0x0000000000200000
>>>>>>>> (XEN) FS: sel=0x0068, attr=0x0c093, limit=0xffffffff,
>>>>>>>> base=0x0000000000200000
>>>>>>>> (XEN) GS: sel=0x0068, attr=0x0c093, limit=0xffffffff,
>>>>>>>> base=0x0000000000200000
>>>>>>>> (XEN) GDTR: limit=0x00001dd8,
>>>>>>>> base=0x0000000000200000
>>>>>>>> (XEN) LDTR: sel=0x0000, attr=0x1c000, limit=0xffffffff,
>>>>>>>> base=0x0000000000000000
>>>>>>>> (XEN) IDTR: limit=0x00000188,
>>>>>>>> base=0x0000000000201df0
>>>>>>>> (XEN) TR: sel=0x0058, attr=0x0008b, limit=0x0000ffff,
>>>>>>>> base=0x0000000000201ff2
>>>>>>>> (XEN) Guest PAT = 0x0000000000000000
>>>>>>>> (XEN) TSC Offset = ffffffe4920110b7
>>>>>>>> (XEN) DebugCtl=0000000000000000 DebugExceptions=0000000000000000
>>>>>>>> (XEN) Interruptibility=0001 ActivityState=0000
>>>>>>>> (XEN) *** Host State ***
>>>>>>>> (XEN) RSP = 0xffff83007e4f7fa0 RIP = 0xffff828c8019aa20
>>>>>>>> (XEN) CS=e008 DS=0000 ES=0000 FS=0000 GS=0000 SS=0000 TR=e040
>>>>>>>> (XEN) FSBase=0000000000000000 GSBase=0000000000000000
>>>>>>>> TRBase=ffff828c802a8b00
>>>>>>>> (XEN) GDTBase=ffff83007e9a3000 IDTBase=ffff83007e62e010
>>>>>>>> (XEN) CR0=0000000080050033 CR3=000000007cfdc000 CR4=00000000000026f0
>>>>>>>> (XEN) Sysenter RSP=ffff83007e4f7fd0 CS:RIP=e008:ffff828c801c7290
>>>>>>>> (XEN) Host PAT = 0x0000000000000000
>>>>>>>> (XEN) *** Control State ***
>>>>>>>> (XEN) PinBased=0000003f CPUBased=b6a1e7fe SecondaryExec=00000041
>>>>>>>> (XEN) EntryControls=000011ff ExitControls=0003efff
>>>>>>>> (XEN) ExceptionBitmap=00044080
>>>>>>>> (XEN) VMEntry: intr_info=80000b0b errcode=00001eac ilen=00000000
>>>>>>>> (XEN) VMExit: intr_info=00000000 errcode=00008000 ilen=00000000
>>>>>>>> (XEN) reason=80000021 qualification=00000000
>>>>>>>> (XEN) IDTVectoring: info=00000000 errcode=00000000
>>>>>>>> (XEN) TPR Threshold = 0x00
>>>>>>>> (XEN) EPT pointer = 0x0000000000000000
>>>>>>>> (XEN) Virtual processor ID = 0x0000
>>>>>>>> (XEN) **************************************
>>>>>>>> (XEN) domain_crash called from vmx.c:2218
>>>>>>>> (XEN) Domain 1 (vcpu#0) crashed on cpu#1:
>>>>>>>> (XEN) ----[ Xen-3.4.0-rc3-pre x86_64 debug=n Not tainted ]----
>>>>>>>> (XEN) CPU: 1
>>>>>>>> (XEN) RIP: 0060:[<000000000000002a>]
>>>>>>>> (XEN) RFLAGS: 0000000000023202 CONTEXT: hvm guest
>>>>>>>> (XEN) rax: 0000000000000007 rbx: 0000000000001490 rcx:
>>>>>>>> 0000000000000000
>>>>>>>> (XEN) rdx: 0000000000001da8 rsi: 0000000000000000 rdi:
>>>>>>>> 0000000000000000
>>>>>>>> (XEN) rbp: 0000000000008ebf rsp: 0000000000000080 r8:
>>>>>>>> 0000000000000000
>>>>>>>> (XEN) r9: 0000000000000000 r10: 0000000000000000 r11:
>>>>>>>> 0000000000000000
>>>>>>>> (XEN) r12: 0000000000000000 r13: 0000000000000000 r14:
>>>>>>>> 0000000000000000
>>>>>>>> (XEN) r15: 0000000000000000 cr0: 0000000080000019 cr4:
>>>>>>>> 0000000000000000
>>>>>>>> (XEN) cr3: 0000000001443000 cr2: 0000000000000000
>>>>>>>> (XEN) ds: 0068 es: 0068 fs: 0068 gs: 0068 ss: 0070 cs: 0060
>>>>>>>>
>>>>>>>> Could it be, that the real mode emulation code has a bug? What does
>>>>>>>> this
>>>>>>>> error means?
>>>>>>>>
>>>>>>>> Tom
>>>>>>>>
>>>>>>>> 2009/4/22 Keir Fraser
>>>>>>>> <
keir.fraser@xxxxxxxxxxxxx<mailto:
keir.fraser@xxxxxxxxxxxxx>>
>>>>>>>> On 22/04/2009 12:18, "Tom Rotenberg"
>>>>>>>> <
tom.rotenberg@xxxxxxxxx<mailto:
tom.rotenberg@xxxxxxxxx>> wrote:
>>>>>>>>
>>>>>>>>> Keir,
>>>>>>>>>
>>>>>>>>> I have applied your patch, and it seemed to work. However, the domain
>>>>>>>>> still
>>>>>>>>> crashes, and now it looks like it's because of the 'LTR' instruction.
>>>>>>>>
>>>>>>>> Try the attached patch. It replaces the one I sent last time, and
>>>>>>>> emulates
>>>>>>>> both LLDT and LTR.
>>>>>>>>
>>>>>>>> -- Keir
>>>>>>>>
>>>>>>>
>>>>>>> Content-Description: ATT00001.txt
>>>>>>>> _______________________________________________
>>>>>>>> Xen-devel mailing list
>>>>>>>>
Xen-devel@xxxxxxxxxxxxxxxxxxx
>>>>>>>>
http://lists.xensource.com/xen-devel
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Tim Deegan <
Tim.Deegan@xxxxxxxxxx>
>>>>>>> Principal Software Engineer, Citrix Systems (R&D) Ltd.
>>>>>>> [Company #02300071, SL9 0DZ, UK.]
>>>>>>
>>>>>
>>>>>
>>>>
>>>> --
>>>> Tim Deegan <
Tim.Deegan@xxxxxxxxxx>
>>>> Principal Software Engineer, Citrix Systems (R&D) Ltd.
>>>> [Company #02300071, SL9 0DZ, UK.]
>>>
>>
>>
>
