Re: [Xen-devel] [xen-unstable] Commit 2ca9fbd739b8a72b16dd790d0fff7b75f5488fb8 AMD IOMMU: allocate IRTE entries instead of using a static mapping, makes dom0 boot process stall several times.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 23.08.13 at 17:11, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
>>>> On 23.08.13 at 17:05, Sander Eikelenboom <linux@xxxxxxxxxxxxxx> wrote:
> 
>> Friday, August 23, 2013, 4:28:43 PM, you wrote:
>> 
>>>>>> On 23.08.13 at 00:51, Sander Eikelenboom <linux@xxxxxxxxxxxxxx> wrote:
>>>> After i got things working on baremetal Linux, i adjusted Xen and 
>>>> hardcoded 
>>>> it to add a mapping for ioapic[6]=00:14.0.
>>>> (the entries for ivrs_ioapic[7] and hpet[0] are actually correct in the 
>>>> bios 
> 
>> 
>>>> tables, so they don't need correction for me at the moment)
>> 
>>> Are you sure about the HPET part of this? I ask because that being
>>> wrong could be an explanation for the stalls you see when using
>>> cpuidle (as that could mean those HPET interrupts needed for
>>> waking CPUs don't arrive).
>> 
>>> Speaking of which - why don't you try whether when not using
>>> FSB-capable HPET channels, the stalls go away? All you'd need
>>> to change is hpet_fsb_cap_lookup() - it ought to return without
>>> doing anything (i.e., if you look at the code, as if
>>> acpi_gbl_FADT.boot_flags had ACPI_FADT_NO_MSI set).
>> 
>> Ok adding:
>> 
>> @@ -392,6 +392,9 @@ static void __init hpet_fsb_cap_lookup(void)
>>      u32 id;
>>      unsigned int i, num_chs;
>> 
>> +    printk(XENLOG_INFO "SEIK HPET: return as if acpi_gbl_FADT.boot_flags & 
>> ACPI_FADT_NO_MSI\n");
>> +    return;
>> +
>>      if ( unlikely(acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_MSI) )
>>          return;
>> 
>> 
>> Indeed made the stalls go away ..
> 
> So if this time you didn't leave a no-cpuidle in place somewhere ;-)
> this makes relatively clear that the stalls are due to the interrupts
> coming from the HPET not reaching their destinations. I still can't
> connect this to the $subject commit yet, though.

Could you provide 'M' and 'V' output for the bad (stalling) case?

Jan


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