On 20/12/2016 17:31, Fam Zheng wrote:
> + hbitmap_iter_init(&iter, s->free_chunks, 1);
> + if (contiguous) {
> + while (true) {
> + bool satisfy = true;
> + next = hbitmap_iter_next(&iter);
> + if (next < 0) {
> + return NULL;
> + }
> + for (i = 1; i < chunks; i++) {
> + if (!hbitmap_get(s->free_chunks, next + i)) {
> + satisfy = false;
> + break;
> + }
> + }
> + if (satisfy) {
> + break;
> + }
> + }
> + hbitmap_reset(s->free_chunks, next, chunks);
> + r = g_new(IOVARange, 1);
> + r->iova = next * pages_per_chunk * getpagesize();
> + r->nr_pages = pages;
> + QSIMPLEQ_INSERT_TAIL(&m.iova_list, r, next);
> + } else {
> + next = hbitmap_iter_next(&iter);
> + while (pages) {
> + uint64_t chunk;
> + if (next < 0) {
> + hbitmap_iter_init(&iter, s->free_chunks, 1);
> + next = hbitmap_iter_next(&iter);
> + }
> + assert(next >= 0);
> + chunk = next;
> + DPRINTF("using chunk %ld\n", chunk);
> + next = hbitmap_iter_next(&iter);
> + hbitmap_reset(s->free_chunks, chunk, 1);
> + if (r && r->iova + r->nr_pages == chunk * pages_per_chunk) {
> + r->nr_pages += MIN(pages, pages_per_chunk);
> + } else {
> + r = g_new(IOVARange, 1);
> + r->iova = chunk * pages_per_chunk * getpagesize();
> + r->nr_pages = MIN(pages, pages_per_chunk);
> + QSIMPLEQ_INSERT_TAIL(&m.iova_list, r, next);
> + }
> + pages -= MIN(pages, pages_per_chunk);
> + }
I'm not sure HBitmap tracking is useful. If we exhaust the IOVA space,
we can just throw everything away with a single VFIO_IOMMU_UNMAP_DMA.
Then replay the RAMBlockNotifier mappings (we need to add this anyway
for hotplug support) and keep on mapping lazily whatever comes later.
Thanks,
Paolo
