From f771b55731fc82b1e8e9ef123f6f1b8d8c92bc63 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Mon, 7 Mar 2022 13:26:25 +1100 Subject: KVM: PPC: Use KVM_CAP_PPC_AIL_MODE_3 Use KVM_CAP_PPC_AIL_MODE_3 to advertise the capability to set the AIL resource mode to 3 with the H_SET_MODE hypercall. This capability differs between processor types and KVM types (PR, HV, Nested HV), and affects guest-visible behaviour. QEMU will implement a cap-ail-mode-3 to control this behaviour[1], and use the KVM CAP if available to determine KVM support[2]. [1] https://lists.nongnu.org/archive/html/qemu-ppc/2022-02/msg00437.html [2] https://lists.nongnu.org/archive/html/qemu-ppc/2022-02/msg00439.html Signed-off-by: Nicholas Piggin Reviewed-by: Fabiano Rosas [mpe: Rebase onto 93b71801a827 from kvm-ppc-cap-210 branch, add EXPORT_SYMBOL] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220222064727.2314380-4-npiggin@gmail.com --- arch/powerpc/kvm/powerpc.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'arch/powerpc/kvm/powerpc.c') diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 9772b176e406..875c30c12db0 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -705,6 +705,23 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = 1; break; #endif + case KVM_CAP_PPC_AIL_MODE_3: + r = 0; + /* + * KVM PR, POWER7, and some POWER9s don't support AIL=3 mode. + * The POWER9s can support it if the guest runs in hash mode, + * but QEMU doesn't necessarily query the capability in time. + */ + if (hv_enabled) { + if (kvmhv_on_pseries()) { + if (pseries_reloc_on_exception()) + r = 1; + } else if (cpu_has_feature(CPU_FTR_ARCH_207S) && + !cpu_has_feature(CPU_FTR_P9_RADIX_PREFETCH_BUG)) { + r = 1; + } + } + break; default: r = 0; break; -- cgit