Re: [PATCH v3] memory: Optimize replay of guest mapping

[Peter Xu]

On Thu, Apr 13, 2023 at 07:00:19PM +0800, Zhenzhong Duan wrote:
> On x86, there are two notifiers registered due to vtd-ir memory
> region splitting the entire address space. During replay of the
> address space for each notifier, the whole address space is
> scanned which is unnecessary. We only need to scan the space
> belong to notifier monitored space.
> 
> While on x86 IOMMU memory region spans over entire address space,
> but on some other platforms(e.g. arm mps3-an547), IOMMU memory
> region is only a window in the whole address space. user could
> register a notifier with arbitrary scope beyond IOMMU memory
> region. Though in current implementation replay is only triggered
> by VFIO and dirty page sync with notifiers derived from memory
> region section, but this isn't guaranteed in the future.
> 
> So, we replay the intersection part of IOMMU memory region and
> IOMMU notifier in memory_region_iommu_replay().
> 
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu