Re: [Qemu-devel] [PATCH][RFC] IOMMU: Add Support to VFIO devices with vIOMMU present

[Aviv B.D.]

On Mon, Mar 21, 2016 at 4:30 AM, Peter Xu <address@hidden> wrote:

On Sat, Mar 19, 2016 at 11:40:04AM +0200, Aviv B.D. wrote:
[...]
> As far as I understand the code, currently there is no way to turn off the
> IOTLB.
> Furthermore. the IOTLB is not implemented as LRU, and actually caches
> (indefinitely)
> any accessed address, without any size constrains. I use those assumptions
> to know
> whether the current invalidation is for unmap operation or map operation.

Please have a look at VTD_IOTLB_MAX_SIZE. It seems to be the size of
the hash.

Btw, I guess it's a much bigger problem if IOTLB has unlimited cache
size...

Thanks. 

-- peterx

You are correct, VTD_IOTLB_MAX_SIZE limits the cache size (and reset the whole cache 

if this threshold exceeds...) I will think on another mechanism to identify the correct 

action for each invalidation.

Thanks,

Aviv.