Re: [Qemu-ppc] [RFC PATCH qemu v3 2/4] vfio: Use different page size for different IOMMU types

[Alex Williamson]

On Tue, 2015-07-14 at 22:21 +1000, Alexey Kardashevskiy wrote:
> The existing memory listener is called on RAM or PCI address space
> which implies potentially different page size. Instead of guessing
> what page size should be used, this replaces a single IOMMU memory
> listener by two, one per supported IOMMU type; listener callbacks
> call the existing helpers with a known page size.
> 
> For now, Type1 uses qemu_real_host_page_mask, sPAPR uses the page size
> from IOMMU.
> 
> As memory_region_iommu_get_page_sizes() asserts on non-IOMMU regions,
> this adds memory_region_is_iommu() to the SPAPR IOMMU listener to skip
> non IOMMU regions (which is an MSIX window) which duplicates
> vfio_listener_skipped_section() a bit.
> 
> Signed-off-by: Alexey Kardashevskiy <address@hidden>
> ---
>  hw/vfio/common.c | 95 
> ++++++++++++++++++++++++++++++++++++++++++++------------
>  1 file changed, 76 insertions(+), 19 deletions(-)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 85ee9b0..aad41e1 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -312,11 +312,11 @@ out:
>      rcu_read_unlock();
>  }
>  
> -static void vfio_listener_region_add(MemoryListener *listener,
> +static void vfio_listener_region_add(VFIOContainer *container,
> +                                     hwaddr page_mask,

Should memory_region_iommu_get_page_sizes() return a hwaddr?

> +                                     MemoryListener *listener,
>                                       MemoryRegionSection *section)
>  {
> -    VFIOContainer *container = container_of(listener, VFIOContainer,
> -                                            iommu_data.type1.listener);
>      hwaddr iova, end;
>      Int128 llend;
>      void *vaddr;
> @@ -330,16 +330,16 @@ static void vfio_listener_region_add(MemoryListener 
> *listener,
>          return;
>      }
>  
> -    if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) 
> !=
> -                 (section->offset_within_region & ~TARGET_PAGE_MASK))) {
> +    if (unlikely((section->offset_within_address_space & ~page_mask) !=
> +                 (section->offset_within_region & ~page_mask))) {
>          error_report("%s received unaligned region", __func__);
>          return;
>      }
>  
> -    iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
> +    iova = ROUND_UP(section->offset_within_address_space, ~page_mask + 1);
>      llend = int128_make64(section->offset_within_address_space);
>      llend = int128_add(llend, section->size);
> -    llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));
> +    llend = int128_and(llend, int128_exts64(page_mask));
>  
>      if (int128_ge(int128_make64(iova), llend)) {
>          return;
> @@ -416,11 +416,11 @@ static void vfio_listener_region_add(MemoryListener 
> *listener,
>      }
>  }
>  
> -static void vfio_listener_region_del(MemoryListener *listener,
> +static void vfio_listener_region_del(VFIOContainer *container,
> +                                     hwaddr page_mask,
> +                                     MemoryListener *listener,
>                                       MemoryRegionSection *section)
>  {
> -    VFIOContainer *container = container_of(listener, VFIOContainer,
> -                                            iommu_data.type1.listener);
>      hwaddr iova, end;
>      int ret;
>  
> @@ -432,8 +432,8 @@ static void vfio_listener_region_del(MemoryListener 
> *listener,
>          return;
>      }
>  
> -    if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) 
> !=
> -                 (section->offset_within_region & ~TARGET_PAGE_MASK))) {
> +    if (unlikely((section->offset_within_address_space & ~page_mask) !=
> +                 (section->offset_within_region & ~page_mask))) {
>          error_report("%s received unaligned region", __func__);
>          return;
>      }
> @@ -459,9 +459,9 @@ static void vfio_listener_region_del(MemoryListener 
> *listener,
>           */
>      }
>  
> -    iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
> +    iova = ROUND_UP(section->offset_within_address_space, ~page_mask + 1);
>      end = (section->offset_within_address_space + 
> int128_get64(section->size)) &
> -          TARGET_PAGE_MASK;
> +          page_mask;
>  
>      if (iova >= end) {
>          return;
> @@ -478,9 +478,66 @@ static void vfio_listener_region_del(MemoryListener 
> *listener,
>      }
>  }
>  
> -static const MemoryListener vfio_memory_listener = {
> -    .region_add = vfio_listener_region_add,
> -    .region_del = vfio_listener_region_del,
> +static void vfio_type1_iommu_listener_region_add(MemoryListener *listener,
> +                                                 MemoryRegionSection 
> *section)
> +{
> +    VFIOContainer *container = container_of(listener, VFIOContainer,
> +                                            iommu_data.type1.listener);
> +
> +    vfio_listener_region_add(container, qemu_real_host_page_mask, listener,
> +                             section);
> +}
> +
> +
> +static void vfio_type1_iommu_listener_region_del(MemoryListener *listener,
> +                                                 MemoryRegionSection 
> *section)
> +{
> +    VFIOContainer *container = container_of(listener, VFIOContainer,
> +                                            iommu_data.type1.listener);
> +
> +    vfio_listener_region_del(container, qemu_real_host_page_mask, listener,
> +                             section);
> +}
> +
> +static const MemoryListener vfio_type1_iommu_listener = {
> +    .region_add = vfio_type1_iommu_listener_region_add,
> +    .region_del = vfio_type1_iommu_listener_region_del,
> +};
> +
> +static void vfio_spapr_iommu_listener_region_add(MemoryListener *listener,
> +                                     MemoryRegionSection *section)
> +{
> +    VFIOContainer *container;
> +    hwaddr page_mask;
> +
> +    if (!memory_region_is_iommu(section->mr)) {
> +        return;
> +    }
> +    container = container_of(listener, VFIOContainer,
> +                             iommu_data.type1.listener);
> +    page_mask = ~(memory_region_iommu_get_page_sizes(section->mr) - 1);
> +    vfio_listener_region_add(container, page_mask, listener, section);
> +}
> +
> +
> +static void vfio_spapr_iommu_listener_region_del(MemoryListener *listener,
> +                                     MemoryRegionSection *section)
> +{
> +    VFIOContainer *container;
> +    hwaddr page_mask;
> +
> +    if (!memory_region_is_iommu(section->mr)) {
> +        return;
> +    }
> +    container = container_of(listener, VFIOContainer,
> +                             iommu_data.type1.listener);
> +    page_mask = ~(memory_region_iommu_get_page_sizes(section->mr) - 1);
> +    vfio_listener_region_del(container, page_mask, listener, section);
> +}
> +
> +static const MemoryListener vfio_spapr_iommu_listener = {
> +    .region_add = vfio_spapr_iommu_listener_region_add,
> +    .region_del = vfio_spapr_iommu_listener_region_del,
>  };


Rather than creating all these wrappers, why don't we create a structure
that gives us callbacks we can use for a shared function?  If we had:

struct VFIOMemoryListener {
        struct MemoryListener listener;
        bool (*filter)(MemoryRegionSection *section);
        hwaddr (page_size)(MemoryRegionSection *section);
        VFIOContainer *container;
}

Then there would be no reason for you to have separate wrappers for
spapr.  VFIOType1 would have a single VFIOMemoryListener, you could have
an array of two.
>  
>  static void vfio_listener_release(VFIOContainer *container)
> @@ -684,7 +741,7 @@ static int vfio_connect_container(VFIOGroup *group, 
> AddressSpace *as)
>              goto free_container_exit;
>          }
>  
> -        container->iommu_data.type1.listener = vfio_memory_listener;
> +        container->iommu_data.type1.listener = vfio_type1_iommu_listener;
>          container->iommu_data.release = vfio_listener_release;
>  
>          memory_listener_register(&container->iommu_data.type1.listener,
> @@ -724,7 +781,7 @@ static int vfio_connect_container(VFIOGroup *group, 
> AddressSpace *as)
>              goto free_container_exit;
>          }
>  
> -        container->iommu_data.type1.listener = vfio_memory_listener;
> +        container->iommu_data.type1.listener = vfio_spapr_iommu_listener;
>          container->iommu_data.release = vfio_listener_release;
>  
>          memory_listener_register(&container->iommu_data.type1.listener,