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-rw-r--r--Documentation/virt/kvm/api.rst59
-rw-r--r--arch/riscv/kvm/vcpu_sbi_replace.c8
-rw-r--r--arch/x86/include/asm/shared/tdx.h1
-rw-r--r--arch/x86/kvm/vmx/tdx.c83
-rw-r--r--include/uapi/linux/kvm.h22
5 files changed, 161 insertions, 12 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 1bd2d42e6424..9abf93ee5f65 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 +7177,62 @@ 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;
+ struct {
+ u64 ret;
+ u64 leaf;
+ u64 r11, r12, r13, r14;
+ } get_tdvmcall_info;
+ };
+ } 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.
+
+* ``TDVMCALL_GET_TD_VM_CALL_INFO``: the guest has requested the support
+status of TDVMCALLs. The output values for the given leaf should be
+placed in fields from ``r11`` to ``r14`` of the ``get_tdvmcall_info``
+field of the union.
+
+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/riscv/kvm/vcpu_sbi_replace.c b/arch/riscv/kvm/vcpu_sbi_replace.c
index 5fbf3f94f1e8..b17fad091bab 100644
--- a/arch/riscv/kvm/vcpu_sbi_replace.c
+++ b/arch/riscv/kvm/vcpu_sbi_replace.c
@@ -103,7 +103,7 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_FENCE_I_SENT);
break;
case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
- if (cp->a2 == 0 && cp->a3 == 0)
+ if ((cp->a2 == 0 && cp->a3 == 0) || cp->a3 == -1UL)
kvm_riscv_hfence_vvma_all(vcpu->kvm, hbase, hmask);
else
kvm_riscv_hfence_vvma_gva(vcpu->kvm, hbase, hmask,
@@ -111,7 +111,7 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_HFENCE_VVMA_SENT);
break;
case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
- if (cp->a2 == 0 && cp->a3 == 0)
+ if ((cp->a2 == 0 && cp->a3 == 0) || cp->a3 == -1UL)
kvm_riscv_hfence_vvma_asid_all(vcpu->kvm,
hbase, hmask, cp->a4);
else
@@ -127,9 +127,9 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID:
/*
* Until nested virtualization is implemented, the
- * SBI HFENCE calls should be treated as NOPs
+ * SBI HFENCE calls should return not supported
+ * hence fallthrough.
*/
- break;
default:
retdata->err_val = SBI_ERR_NOT_SUPPORTED;
}
diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h
index 2f3820342598..d8525e6ef50a 100644
--- a/arch/x86/include/asm/shared/tdx.h
+++ b/arch/x86/include/asm/shared/tdx.h
@@ -80,6 +80,7 @@
#define TDVMCALL_STATUS_RETRY 0x0000000000000001ULL
#define TDVMCALL_STATUS_INVALID_OPERAND 0x8000000000000000ULL
#define TDVMCALL_STATUS_ALIGN_ERROR 0x8000000000000002ULL
+#define TDVMCALL_STATUS_SUBFUNC_UNSUPPORTED 0x8000000000000003ULL
/*
* Bitmasks of exposed registers (with VMM).
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index b952bc673271..1ad20c273f3b 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1212,11 +1212,13 @@ static int tdx_map_gpa(struct kvm_vcpu *vcpu)
/*
* Converting TDVMCALL_MAP_GPA to KVM_HC_MAP_GPA_RANGE requires
* userspace to enable KVM_CAP_EXIT_HYPERCALL with KVM_HC_MAP_GPA_RANGE
- * bit set. If not, the error code is not defined in GHCI for TDX, use
- * TDVMCALL_STATUS_INVALID_OPERAND for this case.
+ * bit set. This is a base call so it should always be supported, but
+ * KVM has no way to ensure that userspace implements the GHCI correctly.
+ * So if KVM_HC_MAP_GPA_RANGE does not cause a VMEXIT, return an error
+ * to the guest.
*/
if (!user_exit_on_hypercall(vcpu->kvm, KVM_HC_MAP_GPA_RANGE)) {
- ret = TDVMCALL_STATUS_INVALID_OPERAND;
+ ret = TDVMCALL_STATUS_SUBFUNC_UNSUPPORTED;
goto error;
}
@@ -1449,20 +1451,85 @@ error:
return 1;
}
+static int tdx_complete_get_td_vm_call_info(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_tdx *tdx = to_tdx(vcpu);
+
+ tdvmcall_set_return_code(vcpu, vcpu->run->tdx.get_tdvmcall_info.ret);
+
+ /*
+ * For now, there is no TDVMCALL beyond GHCI base API supported by KVM
+ * directly without the support from userspace, just set the value
+ * returned from userspace.
+ */
+ tdx->vp_enter_args.r11 = vcpu->run->tdx.get_tdvmcall_info.r11;
+ tdx->vp_enter_args.r12 = vcpu->run->tdx.get_tdvmcall_info.r12;
+ tdx->vp_enter_args.r13 = vcpu->run->tdx.get_tdvmcall_info.r13;
+ tdx->vp_enter_args.r14 = vcpu->run->tdx.get_tdvmcall_info.r14;
+
+ return 1;
+}
+
static int tdx_get_td_vm_call_info(struct kvm_vcpu *vcpu)
{
struct vcpu_tdx *tdx = to_tdx(vcpu);
- if (tdx->vp_enter_args.r12)
- tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_INVALID_OPERAND);
- else {
+ switch (tdx->vp_enter_args.r12) {
+ case 0:
tdx->vp_enter_args.r11 = 0;
+ tdx->vp_enter_args.r12 = 0;
tdx->vp_enter_args.r13 = 0;
tdx->vp_enter_args.r14 = 0;
+ tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_SUCCESS);
+ return 1;
+ case 1:
+ vcpu->run->tdx.get_tdvmcall_info.leaf = tdx->vp_enter_args.r12;
+ vcpu->run->exit_reason = KVM_EXIT_TDX;
+ vcpu->run->tdx.flags = 0;
+ vcpu->run->tdx.nr = TDVMCALL_GET_TD_VM_CALL_INFO;
+ vcpu->run->tdx.get_tdvmcall_info.ret = TDVMCALL_STATUS_SUCCESS;
+ vcpu->run->tdx.get_tdvmcall_info.r11 = 0;
+ vcpu->run->tdx.get_tdvmcall_info.r12 = 0;
+ vcpu->run->tdx.get_tdvmcall_info.r13 = 0;
+ vcpu->run->tdx.get_tdvmcall_info.r14 = 0;
+ vcpu->arch.complete_userspace_io = tdx_complete_get_td_vm_call_info;
+ return 0;
+ default:
+ tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_INVALID_OPERAND);
+ 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)) {
@@ -1472,11 +1539,13 @@ 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;
}
- tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_INVALID_OPERAND);
+ tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_SUBFUNC_UNSUPPORTED);
return 1;
}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index d00b85cb168c..37891580d05d 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 +448,27 @@ 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;
+ struct {
+ __u64 ret;
+ __u64 leaf;
+ __u64 r11, r12, r13, r14;
+ } get_tdvmcall_info;
+ };
+ } tdx;
/* Fix the size of the union. */
char padding[256];
};
generated by cgit v1.2.3 (git 2.39.0) at 2025-08-07 02:47:19 +0300