Re: [Qemu-devel] [PATCH 5/8] vfio: Add guest side IOMMU support

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 08/13/2013 08:07 AM, Alex Williamson wrote:
>> +static void vfio_listener_region_add(MemoryListener *listener,
>> +                                     MemoryRegionSection *section)
>> +{
>> +    VFIOContainer *container = container_of(listener, VFIOContainer,
>> +                                            iommu_data.listener);
>> +    hwaddr iova, end;
>> +    int ret;
>>  
>>      if (vfio_listener_skipped_section(section)) {
>>          DPRINTF("SKIPPING region_add %"HWADDR_PRIx" - %"PRIx64"\n",
>> @@ -1952,19 +2011,51 @@ static void vfio_listener_region_add(MemoryListener *listener,
>>          return;
>>      }
>>  
>> -    vaddr = memory_region_get_ram_ptr(section->mr) +
>> -            section->offset_within_region +
>> -            (iova - section->offset_within_address_space);
>> -
>> -    DPRINTF("region_add %"HWADDR_PRIx" - %"HWADDR_PRIx" [%p]\n",
>> -            iova, end - 1, vaddr);
>> -
>> -    memory_region_ref(section->mr);
>> -    ret = vfio_dma_map(container, iova, end - iova, vaddr, section->readonly);
>> -    if (ret) {
>> -        error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
>> -                     "0x%"HWADDR_PRIx", %p) = %d (%m)",
>> -                     container, iova, end - iova, vaddr, ret);
>> +    if (memory_region_is_iommu(section->mr)) {
>> +        VFIOGuestIOMMU *giommu;
>> +
>> +        DPRINTF("region_add [iommu] %"HWADDR_PRIx" - %"HWADDR_PRIx"\n",
>> +                iova, end - 1);
>> +
>> +        memory_region_ref(section->mr);
>> +        /*
>> +         * FIXME: We should do some checking to see if the
>> +         * capabilities of the host VFIO IOMMU are adequate to model
>> +         * the guest IOMMU
>> +         *
>> +         * FIXME: This assumes that the guest IOMMU is empty of
>> +         * mappings at this point - we should either enforce this, or
>> +         * loop through existing mappings to map them into VFIO.
>> +         *
>> +         * FIXME: For VFIO iommu types which have KVM acceleration to
>> +         * avoid bouncing all map/unmaps through qemu this way, this
>> +         * would be the right place to wire that up (tell the KVM
>> +         * device emulation the VFIO iommu handles to use).
>> +         */
>> +        giommu = g_malloc0(sizeof(*giommu));
>> +        giommu->iommu = section->mr;
>> +        giommu->container = container;
>> +        giommu->n.notify = vfio_iommu_map_notify;
>> +        QLIST_INSERT_HEAD(&container->guest_iommus, giommu, list);
>> +        memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
>> +
>> +    } else if (memory_region_is_ram(section->mr)) {
>> +        void *vaddr;
>> +
>> +        vaddr = memory_region_get_ram_ptr(section->mr) +
>> +                section->offset_within_region +
>> +                (iova - section->offset_within_address_space);
>> +
>> +        DPRINTF("region_add [ram] %"HWADDR_PRIx" - %"HWADDR_PRIx" [%p]\n",
>> +                iova, end - 1, vaddr);
>> +
>> +        memory_region_ref(section->mr);
> 
> 
> Where are these unref'd?


It is already vfio_listener_region_del(), as the original ref() which this
patch just moves around.



-- 
Alexey