Re: [Qemu-devel] [Qemu-arm] [PATCH v7 13/20] hw/arm/smmuv3: Implement IOMMU memory region replay callback

[Auger Eric <eric.auger@redhat.com>]

Hi Linu,

On 14/09/2017 11:27, Linu Cherian wrote:
> Hi Eric,
> 
> On Fri Sep 01, 2017 at 07:21:16PM +0200, Eric Auger wrote:
>> memory_region_iommu_replay() is used for VFIO integration.
>>
>> However its default implementation is not adapted to SMMUv3
>> IOMMU memory region. Indeed the input address range is too
>> huge and its execution is too slow as it calls the translate()
>> callback on each granule.
>>
>> Let's implement the replay callback which hierarchically walk
>> over the page table structure and notify only the segments
>> that are populated with valid entries.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> ---
>>  hw/arm/smmuv3.c     | 36 ++++++++++++++++++++++++++++++++++++
>>  hw/arm/trace-events |  1 +
>>  2 files changed, 37 insertions(+)
>>
>> diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
>> index 8e7d10d..c43bd93 100644
>> --- a/hw/arm/smmuv3.c
>> +++ b/hw/arm/smmuv3.c
>> @@ -657,6 +657,41 @@ static int smmuv3_notify_entry(IOMMUTLBEntry *entry, void *private)
>>      return 0;
>>  }
>>  
>> +/* Unmap the whole notifier's range */
>> +static void smmuv3_unmap_notifier_range(IOMMUNotifier *n)
>> +{
>> +    IOMMUTLBEntry entry;
>> +    hwaddr size = n->end - n->start + 1;
>> +
>> +    entry.target_as = &address_space_memory;
>> +    entry.iova = n->start & ~(size - 1);
>> +    entry.perm = IOMMU_NONE;
>> +    entry.addr_mask = size - 1;
>> +
>> +    memory_region_notify_one(n, &entry);
>> +}
>> +
>> +static void smmuv3_replay(IOMMUMemoryRegion *mr, IOMMUNotifier *n)
>> +{
>> +    SMMUTransCfg cfg = {};
>> +    int ret;
>> +
>> +    trace_smmuv3_replay(mr->parent_obj.name, n, n->start, n->end);
>> +    smmuv3_unmap_notifier_range(n);
>> +
>> +    ret = smmuv3_decode_config(mr, &cfg);
>> +    if (ret) {
>> +        error_report("%s error decoding the configuration for iommu mr=%s",
>> +                     __func__, mr->parent_obj.name);
>> +    }
>>
> 
> On an invalid config being found, shouldnt we return rather than proceeding with
> page table walk. For example on an invalid Stream table entry.
Yes that's correct. I am going to fix that.

Thanks!

Eric
> 
> +
>> +    if (cfg.disabled || cfg.bypassed) {
>> +        return;
>> +    }
>> +    /* walk the page tables and replay valid entries */
>> +    smmu_page_walk(&cfg, 0, (1ULL << (64 - cfg.tsz)) - 1, false,
>> +                   smmuv3_notify_entry, n);
>> +}
>>  static void smmuv3_notify_iova_range(IOMMUMemoryRegion *mr, IOMMUNotifier *n,
>>                                       uint64_t iova, size_t size)
>>  {
>> @@ -1095,6 +1130,7 @@ static void smmuv3_iommu_memory_region_class_init(ObjectClass *klass,
>>  
>>      imrc->translate = smmuv3_translate;
>>      imrc->notify_flag_changed = smmuv3_notify_flag_changed;
>> +    imrc->replay = smmuv3_replay;
>>  }
>>  
>>  static const TypeInfo smmuv3_type_info = {
>> diff --git a/hw/arm/trace-events b/hw/arm/trace-events
>> index 4ac264d..15f84d6 100644
>> --- a/hw/arm/trace-events
>> +++ b/hw/arm/trace-events
>> @@ -46,5 +46,6 @@ smmuv3_cfg_stage(int s, uint32_t oas, uint32_t tsz, uint64_t ttbr, bool aa64, ui
>>  smmuv3_notify_flag_add(const char *iommu) "ADD SMMUNotifier node for iommu mr=%s"
>>  smmuv3_notify_flag_del(const char *iommu) "DEL SMMUNotifier node for iommu mr=%s"
>>  smmuv3_replay_mr(const char *name) "iommu mr=%s"
>> +smmuv3_replay(const char *name, void *n, hwaddr start, hwaddr end) "iommu mr=%s notifier=%p [0x%"PRIx64",0x%"PRIx64"]"
>>  smmuv3_notify_entry(hwaddr iova, hwaddr pa, hwaddr mask, int perm) "iova=0x%"PRIx64" pa=0x%" PRIx64" mask=0x%"PRIx64" perm=%d"
>>  smmuv3_notify_iova_range(const char *name, uint64_t iova, size_t size, void *n) "iommu mr=%s iova=0x%"PRIx64" size=0x%lx n=%p"
>> -- 
>> 2.5.5
>>
>>
>