On Thu, Sep 15, 2022, Christian Borntraeger wrote: > Am 15.09.22 um 15:21 schrieb Christian Borntraeger: > > I am wondering if this will work on s390. On s390 we only call > > mark_page_dirty_in_slot for the kvm_read/write functions but not > > for those done by the guest on fault. We do account those lazily in > > kvm_arch_sync_dirty_log (like x96 in the past). > > > > I think we need to rework the page fault handling on s390 to actually make > use of this. This has to happen anyway somewhen (as indicated by the guest > enter/exit rework from Mark). Right now we handle KVM page faults directly > in the normal system fault handler. It seems we need to make a side turn > into KVM for page faults on guests in the long run. s390's page table management came up in conversation at KVM Forum in the context of a common MMU (or MMUs)[*]. If/when we get an MMU that supports multiple architectures, that would be a perfect opportunity for s390 to switch. I don't know that it'll be feasible to make a common MMU support s390 from the get-go, but at the very least we can keep y'all in the loop and not make it unnecessarily difficult to support s390. [*] https://kvmforum2022.sched.com/event/15jJk
