On 20/06/19 06:02, Peter Xu wrote: > Seems workable, to be explicit - we can even cut it into chunks with > different size to be efficient.
Yes, this is not hard (completely untested): diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index 44b1231157..541538bc6c 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -3388,39 +3388,34 @@ static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n) } assert(start <= end); - size = end - start; + while (end > start) { + size = end - start; + /* Only keep the lowest bit of either size or start. */ + size = MIN(size & -size, start & -start); + /* Should not happen, but limit to address width too just in case */ + size = MIN(size, 1ULL << s->aw_bits); - if (ctpop64(size) != 1) { - /* - * This size cannot format a correct mask. Let's enlarge it to - * suite the minimum available mask. - */ - int n = 64 - clz64(size); - if (n > s->aw_bits) { - /* should not happen, but in case it happens, limit it */ - n = s->aw_bits; - } - size = 1ULL << n; - } + assert((start & (size - 1)) == 0); - entry.target_as = &address_space_memory; - /* Adjust iova for the size */ - entry.iova = n->start & ~(size - 1); - /* This field is meaningless for unmap */ - entry.translated_addr = 0; - entry.perm = IOMMU_NONE; - entry.addr_mask = size - 1; + entry.target_as = &address_space_memory; + entry.iova = start; + /* This field is meaningless for unmap */ + entry.translated_addr = 0; + entry.perm = IOMMU_NONE; + entry.addr_mask = size - 1; - trace_vtd_as_unmap_whole(pci_bus_num(as->bus), - VTD_PCI_SLOT(as->devfn), - VTD_PCI_FUNC(as->devfn), - entry.iova, size); + trace_vtd_as_unmap_whole(pci_bus_num(as->bus), + VTD_PCI_SLOT(as->devfn), + VTD_PCI_FUNC(as->devfn), + entry.iova, size); - map.iova = entry.iova; - map.size = entry.addr_mask; - iova_tree_remove(as->iova_tree, &map); + map.iova = entry.iova; + map.size = entry.addr_mask; + iova_tree_remove(as->iova_tree, &map); - memory_region_notify_one(n, &entry); + memory_region_notify_one(n, &entry); + start += size; + } } static void vtd_address_space_unmap_all(IntelIOMMUState *s) Yan, if something like this works for you, let me know and I will submit it as a proper patch. Paolo