Re: [Xen-devel] [PATCH v4 1/3] VT-d: Check VT-d Device-TLB flush error.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 25.12.15 at 03:53, <kevin.tian@xxxxxxxxx> wrote:
>>  From: Xu, Quan
>> Sent: Wednesday, December 23, 2015 4:26 PM
>> --- a/xen/arch/x86/acpi/power.c
>> +++ b/xen/arch/x86/acpi/power.c
>> @@ -45,6 +45,8 @@ void do_suspend_lowlevel(void);
>> 
>>  static int device_power_down(void)
>>  {
>> +    int rc;
>> +
>>      console_suspend();
>> 
>>      time_suspend();
>> @@ -53,7 +55,9 @@ static int device_power_down(void)
>> 
>>      ioapic_suspend();
>> 
>> -    iommu_suspend();
>> +    rc = iommu_suspend();
>> +    if ( rc )
>> +        return rc;
>> 
>>      lapic_suspend();
>> 
> 
> Looks error handling is not only a problem in VT-d code. Above
> actually should check return values of all suspend callbacks. Just
> checking iommu_suspend is not enough, but it's a good improvement
> anyway...

No, it's not - it leaves the system in a non-working state without
undoing whatever succeeded already.

Jan


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