On Wed, 30 May 2018 20:09:46 +1000
Paul Mackerras <paulus@xxxxxxxxxx> wrote:
> Currently, PR KVM does not implement the configure_mmu operation, and
> so the KVM_PPC_CONFIGURE_V3_MMU ioctl always fails with an EINVAL
> error. This causes recent kernels to fail to boot as a PR KVM guest
> on POWER9, since recent kernels booted in HPT mode do the
> H_REGISTER_PROC_TBL hypercall, which causes userspace (QEMU) to do
> KVM_PPC_CONFIGURE_V3_MMU, which fails.
>
> This implements a minimal configure_mmu operation for PR KVM. It
> succeeds only if the MMU is being configured for HPT mode and no
> process table is being registered. This is enough to get recent
> kernels to boot as a PR KVM guest.
>
> Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
> ---
Reviewed-by: Greg Kurz <groug@xxxxxxxx>
Tested-by: Greg Kurz <groug@xxxxxxxx>
Thanks Paul !
> arch/powerpc/kvm/book3s_pr.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
> index c74a8885427d..b1aff9f83ed0 100644
> --- a/arch/powerpc/kvm/book3s_pr.c
> +++ b/arch/powerpc/kvm/book3s_pr.c
> @@ -1687,6 +1687,17 @@ static int kvm_vm_ioctl_get_smmu_info_pr(struct kvm *kvm,
>
> return 0;
> }
> +
> +static int kvm_configure_mmu_pr(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg)
> +{
> + if (!cpu_has_feature(CPU_FTR_ARCH_300))
> + return -ENODEV;
> + /* Require flags and process table base and size to all be zero. */
> + if (cfg->flags || cfg->process_table)
> + return -EINVAL;
> + return 0;
> +}
> +
> #else
> static int kvm_vm_ioctl_get_smmu_info_pr(struct kvm *kvm,
> struct kvm_ppc_smmu_info *info)
> @@ -1788,6 +1799,7 @@ static struct kvmppc_ops kvm_ops_pr = {
> .arch_vm_ioctl = kvm_arch_vm_ioctl_pr,
> #ifdef CONFIG_PPC_BOOK3S_64
> .hcall_implemented = kvmppc_hcall_impl_pr,
> + .configure_mmu = kvm_configure_mmu_pr,
> #endif
> .giveup_ext = kvmppc_giveup_ext,
> };
