On 07.06.23 15:12, Christoph Hellwig wrote: > On Mon, May 22, 2023 at 10:37:09AM +0200, Juergen Gross wrote: >> In normal cases PCI passthrough in PV guests requires to start the guest >> with e820_host=1. So it should be rather easy to limit allocating the >> 64MB in PV guests to the cases where the memory map has non-RAM regions >> especially in the first 1MB of the memory. >> >> This will cover even hotplug cases. The only case not covered would be a >> guest started with e820_host=1 even if no PCI passthrough was planned. >> But this should be rather rare (at least I hope so). > > So is this an ACK for the patch and can we go ahead with it? As long as above mentioned check of the E820 map is done, yes. If you want I can send a diff to be folded into your patch on Monday. > > (I'd still like to merge swiotlb-xen into swiotlb eventually, but it's > probably not going to happen this merge window) Would be nice. Juergen