From 901f8c3f6feb0225c14b3bc6237850fb921d2f2d Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Mon, 8 Oct 2018 14:24:30 +1100 Subject: [PATCH] KVM: PPC: Book3S HV: Add NO_HASH flag to GET_SMMU_INFO ioctl result This adds a KVM_PPC_NO_HASH flag to the flags field of the kvm_ppc_smmu_info struct, and arranges for it to be set when running as a nested hypervisor, as an unambiguous indication to userspace that HPT guests are not supported. Reporting the KVM_CAP_PPC_MMU_HASH_V3 capability as false could be taken as indicating only that the new HPT features in ISA V3.0 are not supported, leaving it ambiguous whether pre-V3.0 HPT features are supported. Reviewed-by: David Gibson Signed-off-by: Paul Mackerras --- Documentation/virtual/kvm/api.txt | 4 ++++ arch/powerpc/kvm/book3s_hv.c | 4 ++++ include/uapi/linux/kvm.h | 1 + 3 files changed, 9 insertions(+) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index fde48b6..df98b63 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2270,6 +2270,10 @@ The supported flags are: The emulated MMU supports 1T segments in addition to the standard 256M ones. + - KVM_PPC_NO_HASH + This flag indicates that HPT guests are not supported by KVM, + thus all guests must use radix MMU mode. + The "slb_size" field indicates how many SLB entries are supported The "sps" array contains 8 entries indicating the supported base diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 89bcf92..788bc61 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4257,6 +4257,10 @@ static int kvm_vm_ioctl_get_smmu_info_hv(struct kvm *kvm, kvmppc_add_seg_page_size(&sps, 16, SLB_VSID_L | SLB_VSID_LP_01); kvmppc_add_seg_page_size(&sps, 24, SLB_VSID_L); + /* If running as a nested hypervisor, we don't support HPT guests */ + if (kvmhv_on_pseries()) + info->flags |= KVM_PPC_NO_HASH; + return 0; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index d9cec6b..7f2ff3a 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -719,6 +719,7 @@ struct kvm_ppc_one_seg_page_size { #define KVM_PPC_PAGE_SIZES_REAL 0x00000001 #define KVM_PPC_1T_SEGMENTS 0x00000002 +#define KVM_PPC_NO_HASH 0x00000004 struct kvm_ppc_smmu_info { __u64 flags; -- 2.7.4