Re: [Qemu-devel] [PATCH v5 for-2.3 27/28] apci: fix PXB behaviour if used with unsupported BIOS

[Marcel Apfelbaum <marcel@redhat.com>]

On 03/10/2015 05:44 PM, Michael S. Tsirkin wrote:
> On Tue, Mar 10, 2015 at 05:32:13PM +0200, Marcel Apfelbaum wrote:
>> PXB does not work with an unsupported BIOS, but should
>> not interfere with normal OS operation.
>>
>> Fix this by not adding PXB mem/IO chunks to _CRS
>> if they weren't configured by BIOS.
>>
>> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
>> ---
>>   hw/i386/acpi-build.c | 71 +++++++++++++++++++++++++++++++---------------------
>>   1 file changed, 42 insertions(+), 29 deletions(-)
>>
>> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
>> index 2bc8a80..416972c 100644
>> --- a/hw/i386/acpi-build.c
>> +++ b/hw/i386/acpi-build.c
>> @@ -780,6 +780,10 @@ static Aml *build_crs(PcPciInfo *pci, PciInfo *bus_info,
>>               range_base = region->value->address;
>>               range_limit = region->value->address + region->value->size - 1;
>>
>> +            if (range_base == PCI_BAR_UNMAPPED) {
>> +                continue;
>> +            }
>> +
>>               if (!strcmp(region->value->type, "io")) {
>>                   aml_append(crs,
>>                       aml_word_io(aml_min_fixed, aml_max_fixed,
>> @@ -813,41 +817,50 @@ static Aml *build_crs(PcPciInfo *pci, PciInfo *bus_info,
>>
>>               range_base = bridge_info->bus.io_range->base;
>>               range_limit = bridge_info->bus.io_range->limit;
>> -            aml_append(crs,
>> -                aml_word_io(aml_min_fixed, aml_max_fixed,
>> -                            aml_pos_decode, aml_entire_range,
>> -                            0,
>> -                            range_base,
>> -                            range_limit,
>> -                            0,
>> -                            range_limit - range_base + 1));
>> -            crs_range_insert(io_ranges, range_base, range_limit);
>> +            /* PCI Bridge I/O limit is aligned to 4K */
>
> Can't say this comment explains anything.
> So it's aligned - thus if (range_limit >> 12) is same as
> if (range_limit).
I'll use range_base == 0 as invalid value.

Thanks,
Marcel

>
> Also, generally you should test limit>base for bridges.

>
>> +            if (range_limit >> 12) {
>> +                aml_append(crs,
>> +                    aml_word_io(aml_min_fixed, aml_max_fixed,
>> +                                aml_pos_decode, aml_entire_range,
>> +                                0,
>> +                                range_base,
>> +                                range_limit,
>> +                                0,
>> +                                range_limit - range_base + 1));
>> +                crs_range_insert(io_ranges, range_base, range_limit);
>> +            }
>>
>>               range_base = bridge_info->bus.memory_range->base;
>>               range_limit = bridge_info->bus.memory_range->limit;
>> -             aml_append(crs,
>> -                aml_dword_memory(aml_pos_decode, aml_min_fixed,
>> -                                 aml_max_fixed, aml_non_cacheable,
>> -                                 aml_ReadWrite,
>> -                                 0,
>> -                                 range_base,
>> -                                 range_limit,
>> -                                 0,
>> -                                 range_limit - range_base + 1));
>> -            crs_range_insert(mem_ranges, range_base, range_limit);
>> +            /* PCI Bridge MEM limit is aligned to 1M */
>
> same comment here.
>
>> +            if (range_limit >> 20) {
>> +                aml_append(crs,
>> +                    aml_dword_memory(aml_pos_decode, aml_min_fixed,
>> +                                     aml_max_fixed, aml_non_cacheable,
>> +                                     aml_ReadWrite,
>> +                                     0,
>> +                                     range_base,
>> +                                     range_limit,
>> +                                     0,
>> +                                     range_limit - range_base + 1));
>> +                    crs_range_insert(mem_ranges, range_base, range_limit);
>> +            }
>>
>>               range_base = bridge_info->bus.prefetchable_range->base;
>>               range_limit = bridge_info->bus.prefetchable_range->limit;
>> -            aml_append(crs,
>> -                aml_dword_memory(aml_pos_decode, aml_min_fixed,
>> -                                 aml_max_fixed, aml_non_cacheable,
>> -                                 aml_ReadWrite,
>> -                                 0,
>> -                                 range_base,
>> -                                 range_limit,
>> -                                 0,
>> -                                 range_limit - range_base + 1));
>> -            crs_range_insert(mem_ranges, range_base, range_limit);
>> +            /* PCI Bridge Prefetch MEM limit is aligned to 1M */
>> +            if (range_limit >> 20) {
>> +                aml_append(crs,
>> +                    aml_dword_memory(aml_pos_decode, aml_min_fixed,
>> +                                     aml_max_fixed, aml_non_cacheable,
>> +                                     aml_ReadWrite,
>> +                                     0,
>> +                                     range_base,
>> +                                     range_limit,
>> +                                     0,
>> +                                     range_limit - range_base + 1));
>> +                crs_range_insert(mem_ranges, range_base, range_limit);
>> +            }
>>           }
>>       }
>>
>> --
>> 2.1.0