Re: BUG with Win7 and user-return-notifier

Jan Kiszka
2009-10-29T08:32:13Z

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Avi Kivity wrote:
> On 10/29/2009 10:03 AM, Jan Kiszka wrote:
>> Avi Kivity wrote:
>>
>>> On 10/28/2009 10:40 PM, Jan Kiszka wrote:
>>>
>>>>
>>>>> [you can get longer, more detailed traces by using
>>>>> /sys/kernel/debug/tracing/trace instead of dmesg]
>>>>>
>>>>> Oct 28 14:29:56 mchn012c kernel: qemu-sys-7200 0...1. 676996395us :
>>>>> kvm_msr: msr_read c0000080 = 0x500
>>>>> Oct 28 14:29:56 mchn012c kernel: qemu-sys-7200 0...1. 676996403us :
>>>>> kvm_msr: msr_write c0000080 = 0xd01
>>>>>
>>>>> So Windows is setting EFER.SCE and EFER.NX while in long mode -
>>>>> perfectly reasonable. Can you rerun with the attached debug patch?
>>>>>
>>>>>
>>>>>
>>>> Log attached.
>>>>
>>>>
>>> So the last bits are:
>>>
>>> Oct 28 21:26:41 mchn012c kernel: update_transition_efer: efer_offset 4
>>> efer d01
>>> Oct 28 21:26:41 mchn012c kernel: update_transition_efer: ignoring all
>>> bits
>>> Oct 28 21:26:41 mchn012c kernel: setup_msrs: marking efer for no reload
>>>
>>> We're not reloading efer (correctly, as guest efer == host efer), yet
>>> vmx_save_host_state() fails while loading efer. I've looked at
>>> move_msr_up() (which is used by setup_msrs() to partition the msr space
>>> into reloaded and non-reloaded msrs), and it seems correct.
>>>
>>> Can you see any way where update_transition_efer() returns false, yet
>>> efer turns up in the first save_nmsrs entries of vmx->guest_msrs?
>>>
>>>
>> Without understanding the code completely yet: When you push the slot
>> containing EFER around, do you also update msr_offset_efer?
>>
>>
>
> We don't, but msr_offset_efer is only used from
> update_transition_efer(), which is only ever called from setup_msrs()
> immediately after updating msr_offset_efer.

Indeed.

>
> Of course, it should be an argument to update_transition_efer(), I'll
> clean up this leftover.
>

OK, will see that I can debug this later today.

Jan

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