Re: [PATCH kvm-unit-tests 07/10] Correct the tss size

[Avi Kivity <avi@redhat.com>]

  On 08/25/2010 03:27 PM, Jason Wang wrote:
> ----- "Avi Kivity"<avi@redhat.com>  wrote:
>
>> On 08/25/2010 12:40 PM, Jason Wang wrote:
>>> ----- "Avi Kivity"<avi@redhat.com>   wrote:
>>>
>>>> On 08/24/2010 04:47 PM, Jason Wang wrote:
>>>>> TSS size should be 104 byte.
>>>>>
>>>>> Signed-off-by: Jason Wang<jasowang@redhat.com>
>>>>> ---
>>>>>     x86/cstart64.S |    2 +-
>>>>>     1 files changed, 1 insertions(+), 1 deletions(-)
>>>>>
>>>>> diff --git a/x86/cstart64.S b/x86/cstart64.S
>>>>> index 5d358ad..b871153 100644
>>>>> --- a/x86/cstart64.S
>>>>> +++ b/x86/cstart64.S
>>>>> @@ -69,7 +69,7 @@ tss:
>>>>>     	.long 0
>>>>>     	.quad ring0stacktop - i * 4096
>>>> ring 0 stack
>>>>
>>>>>     	.quad 0, 0, 0
>>>> rings 1, 2, 3 stack
>>> Hello avi:
>>>
>>> Rechek with the manual, there's no filed of RSP3. So this patch may
>>> make sense.
>> That is true.  But please redo it to remove one 0 from the line above,
>>
>> not from the IST.
>>
>>> But unfortunately it breaks 64bit vmexit test. Triple
>>> fault happens in setup_args(). Any suggestions or is there any thing
>> I
>>> missed?
>> No idea.  Can you post an ftrace of the crash?
>>
> The trace before triple fault:
>
>          ......
>          qemu-kvm-8101  [002]   243.138507: kvm_entry: vcpu 0
>          qemu-kvm-8101  [002]   243.138508: kvm_exit: reason IO_INSTRUCTION rip 0x400e5f
>          qemu-kvm-8101  [002]   243.138508: kvm_pio: pio_read at 0x510 size 2 count 1
>          qemu-kvm-8101  [002]   243.138512: kvm_entry: vcpu 0
>          qemu-kvm-8101  [002]   243.138513: kvm_exit: reason IO_INSTRUCTION rip 0x400e71
>          qemu-kvm-8101  [002]   243.138514: kvm_emulate_insn: 0:400e71: ec (prot64)
>          qemu-kvm-8101  [002]   243.138515: kvm_pio: pio_write at 0x511 size 1 count 1
>          qemu-kvm-8101  [002]   243.138519: kvm_entry: vcpu 0
>          qemu-kvm-8101  [002]   243.138520: kvm_exit: reason IO_INSTRUCTION rip 0x400e71
>          qemu-kvm-8101  [002]   243.138521: kvm_emulate_insn: 0:400e71: ec (prot64)
>          qemu-kvm-8101  [002]   243.138521: kvm_pio: pio_write at 0x511 size 1 count 1
>          qemu-kvm-8101  [002]   243.138525: kvm_entry: vcpu 0
>          qemu-kvm-8101  [002]   243.138526: kvm_exit: reason CPUID rip 0x400ff7
>          qemu-kvm-8101  [002]   243.138526: kvm_cpuid: func 1 rax 6d3 rbx 800 rcx 80002001 rdx 78bfbfd
>          qemu-kvm-8101  [002]   243.138527: kvm_entry: vcpu 0
>          qemu-kvm-8101  [002]   243.138528: kvm_exit: reason EXCEPTION_NMI rip 0x400271
>          qemu-kvm-8101  [002]   243.138528: kvm_page_fault: address 40f3a0 error_code b
>          qemu-kvm-8101  [002]   243.138530: kvm_entry: vcpu 0
>          qemu-kvm-8101  [002]   243.138531: kvm_exit: reason TRIPLE_FAULT rip 0x400c15
>

What's the corresponding disassembly?

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.