Re: [Qemu-devel] [PATCH v7 14/17] memory: add MemoryRegionIOMMUOps.replay() callback

["Liu, Yi L" <yi.l.liu@intel.com>]

> -----Original Message-----
> From: Qemu-devel [mailto:qemu-devel-bounces+yi.l.liu=intel.com@nongnu.org] On
> Behalf Of Peter Xu
> Sent: Tuesday, February 7, 2017 4:28 PM
> To: qemu-devel@nongnu.org
> Cc: Lan, Tianyu <tianyu.lan@intel.com>; Tian, Kevin <kevin.tian@intel.com>;
> mst@redhat.com; jan.kiszka@siemens.com; jasowang@redhat.com;
> peterx@redhat.com; alex.williamson@redhat.com; bd.aviv@gmail.com; David
> Gibson <david@gibson.dropbear.id.au>
> Subject: [Qemu-devel] [PATCH v7 14/17] memory: add
> MemoryRegionIOMMUOps.replay() callback
> 
> Originally we have one memory_region_iommu_replay() function, which is the
> default behavior to replay the translations of the whole IOMMU region. However,
> on some platform like x86, we may want our own replay logic for IOMMU regions.
> This patch add one more hook for IOMMUOps for the callback, and it'll override the
> default if set.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  include/exec/memory.h | 2 ++
>  memory.c              | 6 ++++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/include/exec/memory.h b/include/exec/memory.h index
> 0767888..30b2a74 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -191,6 +191,8 @@ struct MemoryRegionIOMMUOps {
>      void (*notify_flag_changed)(MemoryRegion *iommu,
>                                  IOMMUNotifierFlag old_flags,
>                                  IOMMUNotifierFlag new_flags);
> +    /* Set this up to provide customized IOMMU replay function */
> +    void (*replay)(MemoryRegion *iommu, IOMMUNotifier *notifier);
>  };
> 
>  typedef struct CoalescedMemoryRange CoalescedMemoryRange; diff --git
> a/memory.c b/memory.c index 7a4f2f9..9c253cc 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -1630,6 +1630,12 @@ void memory_region_iommu_replay(MemoryRegion
> *mr, IOMMUNotifier *n,
>      hwaddr addr, granularity;
>      IOMMUTLBEntry iotlb;
> +    /* If the IOMMU has its own replay callback, override */
> +    if (mr->iommu_ops->replay) {
> +        mr->iommu_ops->replay(mr, n);
> +        return;
> +    }

Hi Alex, Peter,

Will all the other vendors(e.g. PPC, s390, ARM) add their own replay callback
as well? I guess it depends on whether the original replay algorithm work well
for them? Do you have such knowledge?

Regards,
Yi L

> +
>      granularity = memory_region_iommu_get_min_page_size(mr);
> 
>      for (addr = 0; addr < memory_region_size(mr); addr += granularity) {
> --
> 2.7.4
>