Re: [Xen-devel] [PATCH RFC 2/2] AMD IOMMU: allow command line overrides for broken IVRS tables

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Tuesday, August 27, 2013, 6:21:02 PM, you wrote:

>>>> On 27.08.13 at 18:14, Sander Eikelenboom <linux@xxxxxxxxxxxxxx> wrote:
>> Tuesday, August 27, 2013, 5:59:28 PM, you wrote:
>> 
>>>>>> On 27.08.13 at 16:15, Sander Eikelenboom <linux@xxxxxxxxxxxxxx> wrote:
>>>> Where as your implementation seems to only walk the list present from bios 
>>>> and override a specific entry when it's mapping them in parse_ivhd_special 
>>>> ?
>> 
>>> No, the code change to parse_ivrs_table() should be setting up
>>> necessary information.
>> 
>> Well i just checked, and in parse_ivhd_device_special() doing a:
>> 
>> printk(XENLOG_ERR "is apic 0x6 override parsed ? %d ",  test_bit(0x6, 
>> ioapic_cmdline ));
>> 
>> returns 1 ... so the parsing part seems to be OK.
>> 
>> but parse_ivhd_device_special() isn't called for ioapic 0x6, because there 
>> is no entry for it in the bios provided tables in my case.
>> and since that seems to be what is iterated ..

> As said, the handling of missing entries should be done by the tail
> of parse_ivrs_table().

Ah whoops, it does the setup as well .. of course my printk's in 
parse_ivhd_device_special() don't show anything then ...




    /* Each IO-APIC must have been mentioned in the table. */
    for ( apic = 0; !error && iommu_intremap && apic < nr_ioapics; ++apic )
    {
        if ( !nr_ioapic_entries[apic] ||
             ioapic_sbdf[IO_APIC_ID(apic)].pin_2_idx )
            continue;

        if ( !test_bit(IO_APIC_ID(apic), ioapic_cmdline) )
        {
            printk(XENLOG_ERR "IVHD Error: no information for IO-APIC %#x\n",
                   IO_APIC_ID(apic));
            if ( amd_iommu_perdev_intremap )
                return -ENXIO;
        }

wouldn't an extra printk mentioning the addition of an entry from cmdline be 
nice here ?


        ioapic_sbdf[IO_APIC_ID(apic)].pin_2_idx = xmalloc_array(
            u16, nr_ioapic_entries[apic]);
        if ( ioapic_sbdf[IO_APIC_ID(apic)].pin_2_idx )
            memset(ioapic_sbdf[IO_APIC_ID(apic)].pin_2_idx, -1,
                   nr_ioapic_entries[apic] * sizeof(*ioapic_sbdf->pin_2_idx));
        else
        {
            printk(XENLOG_ERR "IVHD Error: Out of memory\n");
            error = -ENOMEM;
        }
    }


> Jan




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