On 20/05/2019 13.20, Paolo Bonzini wrote: > On 16/05/19 13:12, Thomas Huth wrote: >> This patch series enables the KVM selftests for s390x. As a first >> test, the sync_regs from x86 has been adapted to s390x. >> >> Please note that the ucall() interface is not used yet - since >> s390x neither has PIO nor MMIO, this needs some more work first >> before it becomes usable (we likely should use a DIAG hypercall >> here, which is what the sync_reg test is currently using, too...). > > No objections at all, though it would be like to have ucall plumbed in > from the beginning. I'm still looking at the ucall interface ... what I don't quite get yet is the question why the ucall_type there is selectable during runtime? Are there plans to have test that could either use UCALL_PIO or UCALL_MMIO? If not, what about moving ucall_init() and ucall() to architecture specific code in tools/testing/selftests/kvm/lib/aarch64/ and tools/testing/selftests/kvm/lib/x86_64 instead, and to remove the ucall_type stuff again (so that x86 is hard-wired to PIO and aarch64 is hard-wired to MMIO)? ... then I could add a DIAG-based ucall on s390x more easily, I think. Thomas