Re: BUG with Win7 and user-return-notifier

Avi Kivity
2009-10-29T07:37:19Z

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?

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.