On 10/06/2017 02:48 PM, Paolo Bonzini wrote:
On 06/10/2017 14:46, Maxime Coquelin wrote:
addr = ((iotlb.translated_addr & ~iotlb.addr_mask)
| (addr & iotlb.addr_mask));
- *plen = MIN(*plen, (addr | iotlb.addr_mask) - addr + 1);
+ page_mask = iotlb.addr_mask;
Should this be "page_mask &= iotlb.addr_mask"?
If you have multiple IOMMUs on top of each other (yeah, I know...) I
think the smallest size should win. This is also consistent with the
MIN in the line below.
I agree, but changin to "page_mask &= iotlb.addr_mask" will not be
enough, we also have to change the init value. Else we will always end
up with 0xfff.
Maybe we could do as plen was handled before, i.e. setting page_mask
init value to (hwaddr)(-1), and after the loop set it to
~TARGET_PAGE_MASK if it hasn't been changed.
Does that sound reasonable?
True that, in fact it makes sense for the "IOTLB entry" to represent all
of memory if there's no IOMMU at all.
Indeed, that makes sense as no iommu means identity mapping. It would
moreover improve performance, as the vhost backend will only have a
single IOTLB entry in its cache.
Maybe it is better to wait for Peter to understand the reason he limited
it to the target page size?
Thanks,
Maxime
Thanks,
Paolo
