On 10/07/2017 16:59, Stefan Hajnoczi wrote:
>> +static void nvme_dma_map(BlockDriverState *bs, void *host, size_t size)
>> +{
>> + BDRVNVMeState *s = bs->opaque;
>> +
>> + nvme_vfio_dma_map(s->vfio, host, size, false, NULL);
> Since temporary=false repeated calls to map/unmap will run out of space
> and stop working after some time?Yes, the point of bdrv_dma_map/unmap is to add a permanent mapping. Temporary mappings are only valid inside nvme.c, because the corresponding iova is not recorded anywhere. Instead, bdrv_dma_map/unmap cache the iova just like we do for RAMBlock areas during system emulation. The solution is simply not to do that, just like img_bench only calls map/unmap once. If it happens, things just become slower as the driver falls back to temporary mappings. Paolo
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