diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 1b94cced0105..414b7fe1cf7b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6207,6 +6207,29 @@ KVM_RUN_BUS_LOCK flag is used to distinguish between them. This capability can be used to check / enable 2nd DAWR feature provided by POWER10 processor. +7.25 KVM_CAP_SGX_ATTRIBUTE +---------------------- + +:Architectures: x86 +:Target: VM +:Parameters: args[0] is a file handle of a SGX attribute file in securityfs +:Returns: 0 on success, -EINVAL if the file handle is invalid or if a requested + attribute is not supported by KVM. + +KVM_CAP_SGX_ATTRIBUTE enables a userspace VMM to grant a VM access to one or +more priveleged enclave attributes. args[0] must hold a file handle to a valid +SGX attribute file corresponding to an attribute that is supported/restricted +by KVM (currently only PROVISIONKEY). + +The SGX subsystem restricts access to a subset of enclave attributes to provide +additional security for an uncompromised kernel, e.g. use of the PROVISIONKEY +is restricted to deter malware from using the PROVISIONKEY to obtain a stable +system fingerprint. To prevent userspace from circumventing such restrictions +by running an enclave in a VM, KVM prevents access to privileged attributes by +default. + +See Documentation/x86/sgx/2.Kernel-internals.rst for more details. + 8. Other capabilities. ====================== diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 29365c11bf27..2ae061586677 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -849,7 +849,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) * expected to derive it from supported XCR0. */ entry->eax &= SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT | - /* PROVISIONKEY | */ SGX_ATTR_EINITTOKENKEY | + SGX_ATTR_PROVISIONKEY | SGX_ATTR_EINITTOKENKEY | SGX_ATTR_KSS; entry->ebx &= 0; break; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d4063bec8ce3..d4cdab15238b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -75,6 +75,7 @@ #include #include #include +#include #include #define CREATE_TRACE_POINTS @@ -3804,6 +3805,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_X86_USER_SPACE_MSR: case KVM_CAP_X86_MSR_FILTER: case KVM_CAP_ENFORCE_PV_FEATURE_CPUID: +#ifdef CONFIG_X86_SGX_KVM + case KVM_CAP_SGX_ATTRIBUTE: +#endif r = 1; break; case KVM_CAP_SET_GUEST_DEBUG2: @@ -5392,6 +5396,23 @@ split_irqchip_unlock: kvm->arch.bus_lock_detection_enabled = true; r = 0; break; +#ifdef CONFIG_X86_SGX_KVM + case KVM_CAP_SGX_ATTRIBUTE: { + unsigned long allowed_attributes = 0; + + r = sgx_set_attribute(&allowed_attributes, cap->args[0]); + if (r) + break; + + /* KVM only supports the PROVISIONKEY privileged attribute. */ + if ((allowed_attributes & SGX_ATTR_PROVISIONKEY) && + !(allowed_attributes & ~SGX_ATTR_PROVISIONKEY)) + kvm->arch.sgx_provisioning_allowed = true; + else + r = -EINVAL; + break; + } +#endif default: r = -EINVAL; break; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 727010788eff..162b7e044c8b 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1079,6 +1079,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_X86_BUS_LOCK_EXIT 193 #define KVM_CAP_PPC_DAWR1 194 #define KVM_CAP_SET_GUEST_DEBUG2 195 +#define KVM_CAP_SGX_ATTRIBUTE 196 #ifdef KVM_CAP_IRQ_ROUTING