Re: [Qemu-devel] [PATCH V2 4/4] hw/apci: handle 64-bit MMIO regions correctly

[Marcel Apfelbaum <marcel@redhat.com>]

On 05/16/2016 02:19 PM, Igor Mammedov wrote:
> On Sun, 15 May 2016 22:23:34 +0300
> Marcel Apfelbaum <marcel@redhat.com> wrote:
>
>> In build_crs(), the calculation and merging of the ranges already happens
>> in 64-bit, but the entry boundaries are silently truncated to 32-bit in the
>> call to aml_dword_memory(). Fix it by handling the 64-bit MMIO ranges separately.
>> This fixes 64-bit BARs behind PXBs.
>>
>> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
>> ---
>>   hw/i386/acpi-build.c | 53 +++++++++++++++++++++++++++++++++++++++++++---------
>>   1 file changed, 44 insertions(+), 9 deletions(-)
>>
>> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
>> index 78f25ef..aaf4a34 100644
>> --- a/hw/i386/acpi-build.c
>> +++ b/hw/i386/acpi-build.c
>> @@ -739,18 +739,22 @@ static void crs_range_free(gpointer data)
>>   typedef struct CrsRangeSet {
>>       GPtrArray *io_ranges;
>>       GPtrArray *mem_ranges;
>> +    GPtrArray *mem_64bit_ranges;
>>    } CrsRangeSet;
>>
>>   static void crs_range_set_init(CrsRangeSet *range_set)
>>   {
>>       range_set->io_ranges = g_ptr_array_new_with_free_func(crs_range_free);
>>       range_set->mem_ranges = g_ptr_array_new_with_free_func(crs_range_free);
>> +    range_set->mem_64bit_ranges =
>> +            g_ptr_array_new_with_free_func(crs_range_free);
>>   }
>>
>>   static void crs_range_set_free(CrsRangeSet *range_set)
>>   {
>>       g_ptr_array_free(range_set->io_ranges, true);
>>       g_ptr_array_free(range_set->mem_ranges, true);
>> +    g_ptr_array_free(range_set->mem_64bit_ranges, true);
>>   }
>>
>>   static gint crs_range_compare(gconstpointer a, gconstpointer b)
>> @@ -908,8 +912,14 @@ static Aml *build_crs(PCIHostState *host, CrsRangeSet *range_set)
>>                * that do not support multiple root buses
>>                */
>>               if (range_base && range_base <= range_limit) {
>> -                crs_range_insert(temp_range_set.mem_ranges,
>> -                                 range_base, range_limit);
>> +                uint64_t length = range_limit - range_base + 1;
>> +                if (range_limit <= UINT32_MAX && length <= UINT32_MAX) {
>> +                    crs_range_insert(temp_range_set.mem_ranges,
>> +                                     range_base, range_limit);
>> +                } else {
>> +                    crs_range_insert(temp_range_set.mem_64bit_ranges,
>> +                                     range_base, range_limit);
>> +                }
>>               }
>>
>>               range_base =
>> @@ -922,8 +932,14 @@ static Aml *build_crs(PCIHostState *host, CrsRangeSet *range_set)
>>                * that do not support multiple root buses
>>                */
>>               if (range_base && range_base <= range_limit) {
>> -                crs_range_insert(temp_range_set.mem_ranges,
>> -                                 range_base, range_limit);
>> +                uint64_t length = range_limit - range_base + 1;
>> +                if (range_limit <= UINT32_MAX && length <= UINT32_MAX) {
>> +                    crs_range_insert(temp_range_set.mem_ranges,
>> +                                     range_base, range_limit);
>> +                } else {
>> +                    crs_range_insert(temp_range_set.mem_64bit_ranges,
>> +                                     range_base, range_limit);
>> +                }
>>               }
>>           }
>>       }
>> @@ -951,6 +967,19 @@ static Aml *build_crs(PCIHostState *host, CrsRangeSet *range_set)
>>           crs_range_insert(range_set->mem_ranges, entry->base, entry->limit);
>>       }
>>
>> +    crs_range_merge(temp_range_set.mem_64bit_ranges);
>> +    for (i = 0; i < temp_range_set.mem_64bit_ranges->len; i++) {
>> +        entry = g_ptr_array_index(temp_range_set.mem_64bit_ranges, i);
>> +        aml_append(crs,
>> +                   aml_qword_memory(AML_POS_DECODE, AML_MIN_FIXED,
>> +                                    AML_MAX_FIXED, AML_NON_CACHEABLE,
>> +                                    AML_READ_WRITE,
>> +                                    0, entry->base, entry->limit, 0,
>> +                                    entry->limit - entry->base + 1));
>> +        crs_range_insert(range_set->mem_64bit_ranges,
>> +                         entry->base, entry->limit);
>> +    }
> instead of adding another field, wouldn't following be a simpler approach:
>

This would be enough if we only need to create the ACPI table entries.
However we need the mem_64bit_ranges field (I assume you are talking about it)
for "accounting":
We need to extract 'free' ranges given the used one for MMIO and 64-BIT MMIO
separately, for each of them  we will supply a different PCI Window.

The approach I chose is easier to understand IMO:
We have IO, MMIO and 64-MMIO ranges. For each of them we have a different window, but
we apply the same algorithm. Unifying MMIO and 64-MMIO will not give us a real
advantage, as the code we suppress for building the ACPI tables will become
twice as long when we do the 'accounting'. (see: crs_replace_with_free_ranges)

Thanks,
Marcel


> for (i = 0; i < temp_range_set.mem_ranges->len; i++) {
>      entry = g_ptr_array_index(temp_range_set.mem_ranges, i);
>      if (range_limit <= UINT32_MAX && length <= UINT32_MAX) {
>         aml_dword_memory(...);
>      } else {
>         aml_qword_memory(...);
>      }
>
>
>> +
>>       crs_range_set_free(&temp_range_set);
>>
>>       aml_append(crs,
>> @@ -2182,11 +2211,17 @@ build_dsdt(GArray *table_data, GArray *linker,
>>       }
>>
>>       if (pci->w64.begin) {
>> -        aml_append(crs,
>> -            aml_qword_memory(AML_POS_DECODE, AML_MIN_FIXED, AML_MAX_FIXED,
>> -                             AML_CACHEABLE, AML_READ_WRITE,
>> -                             0, pci->w64.begin, pci->w64.end - 1, 0,
>> -                             pci->w64.end - pci->w64.begin));
>> +        crs_replace_with_free_ranges(crs_range_set.mem_64bit_ranges,
>> +                                     pci->w64.begin, pci->w64.end - 1);
>> +        for (i = 0; i < crs_range_set.mem_64bit_ranges->len; i++) {
>> +            entry = g_ptr_array_index(crs_range_set.mem_64bit_ranges, i);
>> +            aml_append(crs,
>> +                       aml_qword_memory(AML_POS_DECODE, AML_MIN_FIXED,
>> +                                        AML_MAX_FIXED,
>> +                                        AML_CACHEABLE, AML_READ_WRITE,
>> +                                        0, entry->base, entry->limit,
>> +                                        0, entry->limit - entry->base + 1));
>> +        }
>>       }
>>
>>       if (misc->tpm_version != TPM_VERSION_UNSPEC) {
>