diff options
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 49 | ||||
| -rw-r--r-- | arch/x86/kvm/vmx/tdx.c | 32 | ||||
| -rw-r--r-- | include/uapi/linux/kvm.h | 17 |
3 files changed, 97 insertions, 1 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 1bd2d42e6424..115ec3c2b641 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6645,7 +6645,8 @@ to the byte array. .. note:: For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR, KVM_EXIT_XEN, - KVM_EXIT_EPR, KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR the corresponding + KVM_EXIT_EPR, KVM_EXIT_HYPERCALL, KVM_EXIT_TDX, + KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR the corresponding operations are complete (and guest state is consistent) only after userspace has re-entered the kernel with KVM_RUN. The kernel side will first finish incomplete operations and then check for pending signals. @@ -7176,6 +7177,52 @@ The valid value for 'flags' is: :: + /* KVM_EXIT_TDX */ + struct { + __u64 flags; + __u64 nr; + union { + struct { + u64 ret; + u64 data[5]; + } unknown; + struct { + u64 ret; + u64 gpa; + u64 size; + } get_quote; + }; + } tdx; + +Process a TDVMCALL from the guest. KVM forwards select TDVMCALL based +on the Guest-Hypervisor Communication Interface (GHCI) specification; +KVM bridges these requests to the userspace VMM with minimal changes, +placing the inputs in the union and copying them back to the guest +on re-entry. + +Flags are currently always zero, whereas ``nr`` contains the TDVMCALL +number from register R11. The remaining field of the union provide the +inputs and outputs of the TDVMCALL. Currently the following values of +``nr`` are defined: + +* ``TDVMCALL_GET_QUOTE``: the guest has requested to generate a TD-Quote +signed by a service hosting TD-Quoting Enclave operating on the host. +Parameters and return value are in the ``get_quote`` field of the union. +The ``gpa`` field and ``size`` specify the guest physical address +(without the shared bit set) and the size of a shared-memory buffer, in +which the TDX guest passes a TD Report. The ``ret`` field represents +the return value of the GetQuote request. When the request has been +queued successfully, the TDX guest can poll the status field in the +shared-memory area to check whether the Quote generation is completed or +not. When completed, the generated Quote is returned via the same buffer. + +KVM may add support for more values in the future that may cause a userspace +exit, even without calls to ``KVM_ENABLE_CAP`` or similar. In this case, +it will enter with output fields already valid; in the common case, the +``unknown.ret`` field of the union will be ``TDVMCALL_STATUS_SUBFUNC_UNSUPPORTED``. +Userspace need not do anything if it does not wish to support a TDVMCALL. +:: + /* Fix the size of the union. */ char padding[256]; }; diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 5d100c240ab3..b619a3478983 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1465,6 +1465,36 @@ static int tdx_get_td_vm_call_info(struct kvm_vcpu *vcpu) return 1; } +static int tdx_complete_simple(struct kvm_vcpu *vcpu) +{ + tdvmcall_set_return_code(vcpu, vcpu->run->tdx.unknown.ret); + return 1; +} + +static int tdx_get_quote(struct kvm_vcpu *vcpu) +{ + struct vcpu_tdx *tdx = to_tdx(vcpu); + u64 gpa = tdx->vp_enter_args.r12; + u64 size = tdx->vp_enter_args.r13; + + /* The gpa of buffer must have shared bit set. */ + if (vt_is_tdx_private_gpa(vcpu->kvm, gpa)) { + tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_INVALID_OPERAND); + return 1; + } + + vcpu->run->exit_reason = KVM_EXIT_TDX; + vcpu->run->tdx.flags = 0; + vcpu->run->tdx.nr = TDVMCALL_GET_QUOTE; + vcpu->run->tdx.get_quote.ret = TDVMCALL_STATUS_SUBFUNC_UNSUPPORTED; + vcpu->run->tdx.get_quote.gpa = gpa & ~gfn_to_gpa(kvm_gfn_direct_bits(tdx->vcpu.kvm)); + vcpu->run->tdx.get_quote.size = size; + + vcpu->arch.complete_userspace_io = tdx_complete_simple; + + return 0; +} + static int handle_tdvmcall(struct kvm_vcpu *vcpu) { switch (tdvmcall_leaf(vcpu)) { @@ -1474,6 +1504,8 @@ static int handle_tdvmcall(struct kvm_vcpu *vcpu) return tdx_report_fatal_error(vcpu); case TDVMCALL_GET_TD_VM_CALL_INFO: return tdx_get_td_vm_call_info(vcpu); + case TDVMCALL_GET_QUOTE: + return tdx_get_quote(vcpu); default: break; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index d00b85cb168c..e23e7286ad1a 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -178,6 +178,7 @@ struct kvm_xen_exit { #define KVM_EXIT_NOTIFY 37 #define KVM_EXIT_LOONGARCH_IOCSR 38 #define KVM_EXIT_MEMORY_FAULT 39 +#define KVM_EXIT_TDX 40 /* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */ @@ -447,6 +448,22 @@ struct kvm_run { __u64 gpa; __u64 size; } memory_fault; + /* KVM_EXIT_TDX */ + struct { + __u64 flags; + __u64 nr; + union { + struct { + __u64 ret; + __u64 data[5]; + } unknown; + struct { + __u64 ret; + __u64 gpa; + __u64 size; + } get_quote; + }; + } tdx; /* Fix the size of the union. */ char padding[256]; }; |