From: Paul Mackerras Date: Fri, 18 May 2018 11:49:28 +0000 (+1000) Subject: KVM: PPC: Book3S PR: Enable use on POWER9 inside HPT-mode guests X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ec531d027ab29b0cfa1c80c8af561b0e74bd4283;p=linux.git KVM: PPC: Book3S PR: Enable use on POWER9 inside HPT-mode guests This relaxes the restriction on using PR KVM on POWER9. The existing code does work inside a guest partition running in HPT mode, because hypercalls such as H_ENTER use the old HPTE format, not the new format used by POWER9, and so no change to PR KVM's HPT manipulation code is required. PR KVM will still refuse to run if the kernel is using radix translation or if it is running bare-metal. Signed-off-by: Paul Mackerras --- diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 67061d399cd9e..3d0251edc13c1 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -1735,9 +1735,16 @@ static void kvmppc_core_destroy_vm_pr(struct kvm *kvm) static int kvmppc_core_check_processor_compat_pr(void) { /* - * Disable KVM for Power9 untill the required bits merged. + * PR KVM can work on POWER9 inside a guest partition + * running in HPT mode. It can't work if we are using + * radix translation (because radix provides no way for + * a process to have unique translations in quadrant 3) + * or in a bare-metal HPT-mode host (because POWER9 + * uses a modified HPTE format which the PR KVM code + * has not been adapted to use). */ - if (cpu_has_feature(CPU_FTR_ARCH_300)) + if (cpu_has_feature(CPU_FTR_ARCH_300) && + (radix_enabled() || cpu_has_feature(CPU_FTR_HVMODE))) return -EIO; return 0; }