Re: [PATCH v4 07/14] vfio/common: Add helper to consolidate iova/end calculation

[Joao Martins]

On 07/03/2023 09:52, Avihai Horon wrote:
> 
> On 07/03/2023 4:02, Joao Martins wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> In preparation to be used in device dirty tracking, move the code that
>> calculates a iova/end range from the container/section.  This avoids
>> duplication on the common checks across listener callbacks.
>>
>> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
>> ---
>>   hw/vfio/common.c | 37 ++++++++++++++++++++++++++++++-------
>>   1 file changed, 30 insertions(+), 7 deletions(-)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 54b4a4fc7daf..3a6491dbc523 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -961,6 +961,35 @@ static bool
>> vfio_listener_valid_section(MemoryRegionSection *section)
>>       return true;
>>   }
>>
>> +/*
>> + * Called for the dirty tracking memory listener to calculate the iova/end
>> + * for a given memory region section.
>> + */
> 
> Should we just delete this comment? The function name is pretty clear.
> Besides that, the comment is not completely accurate -- in this patch we are 
> not
> using it yet for dirty tracking and it's also used for region_{add,del}.
> 
Yes, let me delete it.

> Thanks.
> 
>> +static bool vfio_get_section_iova_range(VFIOContainer *container,
>> +                                        MemoryRegionSection *section,
>> +                                        hwaddr *out_iova, hwaddr *out_end,
>> +                                        Int128 *out_llend)
>> +{
>> +    Int128 llend;
>> +    hwaddr iova;
>> +
>> +    iova = REAL_HOST_PAGE_ALIGN(section->offset_within_address_space);
>> +    llend = int128_make64(section->offset_within_address_space);
>> +    llend = int128_add(llend, section->size);
>> +    llend = int128_and(llend, int128_exts64(qemu_real_host_page_mask()));
>> +
>> +    if (int128_ge(int128_make64(iova), llend)) {
>> +        return false;
>> +    }
>> +
>> +    *out_iova = iova;
>> +    *out_end = int128_get64(int128_sub(llend, int128_one()));
>> +    if (out_llend) {
>> +        *out_llend = llend;
>> +    }
>> +    return true;
>> +}
>> +
>>   static void vfio_listener_region_add(MemoryListener *listener,
>>                                        MemoryRegionSection *section)
>>   {
>> @@ -976,12 +1005,7 @@ static void vfio_listener_region_add(MemoryListener
>> *listener,
>>           return;
>>       }
>>
>> -    iova = REAL_HOST_PAGE_ALIGN(section->offset_within_address_space);
>> -    llend = int128_make64(section->offset_within_address_space);
>> -    llend = int128_add(llend, section->size);
>> -    llend = int128_and(llend, int128_exts64(qemu_real_host_page_mask()));
>> -
>> -    if (int128_ge(int128_make64(iova), llend)) {
>> +    if (!vfio_get_section_iova_range(container, section, &iova, &end, 
>> &llend)) {
>>           if (memory_region_is_ram_device(section->mr)) {
>>               trace_vfio_listener_region_add_no_dma_map(
>>                   memory_region_name(section->mr),
>> @@ -991,7 +1015,6 @@ static void vfio_listener_region_add(MemoryListener
>> *listener,
>>           }
>>           return;
>>       }
>> -    end = int128_get64(int128_sub(llend, int128_one()));
>>
>>       if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) {
>>           hwaddr pgsize = 0;
>> -- 
>> 2.17.2
>>