On Wed, 2017-10-18 at 20:00 +1100, Alexey Kardashevskiy wrote: > > > > With radix, the HW will honor the G bit set in the guest page tables. > > > I am sure that you know better, Paul just pointed me to this: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/kvm/book3s_64_mmu_radix.c?h=v4.13#n403 It's in the architecture somewhere, if you look at 3.0B in the radix section about nested radix, there's a table for the nesting of attributes. Here you'll see that regardless of the G bit value set by the host, the HW will use the G bit value set by the guest. However, we should still provide a way to exploit WC if anything for things like DPDK. Cheers, Ben.
