>@@ -1870,6 +1873,37 @@ static int __kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data,
>
> data = (u32)data;
> break;
>+ case MSR_IA32_FRED_STKLVLS:
>+ if (!guest_cpu_cap_has(vcpu, X86_FEATURE_FRED))
>+ return 1;
Return KVM_MSR_RET_UNSUPPORTED instead of 1.
KVM's uAPI allows userspace to read MSRs and write 0 to MSRs even if an MSR
isn't supported according to guest CPUIDs. Returning KVM_MSR_RET_UNSUPPORTED
allows kvm_do_msr_access() to suppress the failure when needed to comply with
the uAPI.
For more details, see kvm_do_msr_access().
>+ break;
>+ case MSR_IA32_FRED_RSP0 ... MSR_IA32_FRED_RSP3:
>+ case MSR_IA32_FRED_SSP1 ... MSR_IA32_FRED_CONFIG:
>+ u64 reserved_bits = 0;
>+
>+ if (!guest_cpu_cap_has(vcpu, X86_FEATURE_FRED))
>+ return 1;
Ditto here and for __kvm_get_msr() below.
>+
>+ if (is_noncanonical_msr_address(data, vcpu))
>+ return 1;
>+
>+ switch (index) {
>+ case MSR_IA32_FRED_CONFIG:
>+ reserved_bits = BIT_ULL(11) | GENMASK_ULL(5, 4) | BIT_ULL(2);
>+ break;
>+ case MSR_IA32_FRED_RSP0 ... MSR_IA32_FRED_RSP3:
>+ reserved_bits = GENMASK_ULL(5, 0);
>+ break;
>+ case MSR_IA32_FRED_SSP1 ... MSR_IA32_FRED_SSP3:
>+ reserved_bits = GENMASK_ULL(2, 0);
>+ break;
>+ default:
>+ WARN_ON_ONCE(1);
>+ return 1;
>+ }
>+ if (data & reserved_bits)
>+ return 1;
>+ break;
> }
>
> msr.data = data;
>@@ -1914,6 +1948,10 @@ int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data,
> !guest_cpu_cap_has(vcpu, X86_FEATURE_RDPID))
> return 1;
> break;
>+ case MSR_IA32_FRED_RSP0 ... MSR_IA32_FRED_CONFIG:
>+ if (!guest_cpu_cap_has(vcpu, X86_FEATURE_FRED))
>+ return 1;
>+ break;
> }
>
> msr.index = index;
>@@ -7365,6 +7403,10 @@ static void kvm_probe_msr_to_save(u32 msr_index)
> if (!(kvm_get_arch_capabilities() & ARCH_CAP_TSX_CTRL_MSR))
> return;
> break;
>+ case MSR_IA32_FRED_RSP0 ... MSR_IA32_FRED_CONFIG:
>+ if (!kvm_cpu_cap_has(X86_FEATURE_FRED))
>+ return;
>+ break;
> default:
> break;
> }
>--
>2.50.1
>
