1 files changed, 60 insertions, 0 deletions
diff --git a/drivers/pci/tsm.c b/drivers/pci/tsm.c
index 39de91a47a26..5e57501f693e 100644
--- a/drivers/pci/tsm.c
+++ b/drivers/pci/tsm.c
@@ -353,6 +353,66 @@ int pci_tsm_bind(struct pci_dev *pdev, struct kvm *kvm, u32 tdi_id)
 }
 EXPORT_SYMBOL_GPL(pci_tsm_bind);
 
+/**
+ * pci_tsm_guest_req() - helper to marshal guest requests to the TSM driver
+ * @pdev: @pdev representing a bound tdi
+ * @scope: caller asserts this passthrough request is limited to TDISP operations
+ * @req_in: Input payload forwarded from the guest
+ * @in_len: Length of @req_in
+ * @req_out: Output payload buffer response to the guest
+ * @out_len: Length of @req_out on input, bytes filled in @req_out on output
+ * @tsm_code: Optional TSM arch specific result code for the guest TSM
+ *
+ * This is a common entry point for requests triggered by userspace KVM-exit
+ * service handlers responding to TDI information or state change requests. The
+ * scope parameter limits requests to TDISP state management, or limited debug.
+ * This path is only suitable for commands and results that are the host kernel
+ * has no use, the host is only facilitating guest to TSM communication.
+ *
+ * Returns 0 on success and -error on failure and positive "residue" on success
+ * but @req_out is filled with less then @out_len, or @req_out is NULL and a
+ * residue number of bytes were not consumed from @req_in.  On success or
+ * failure @tsm_code may be populated with a TSM implementation specific result
+ * code for the guest to consume.
+ *
+ * Context: Caller is responsible for calling this within the pci_tsm_bind()
+ * state of the TDI.
+ */
+ssize_t pci_tsm_guest_req(struct pci_dev *pdev, enum pci_tsm_req_scope scope,
+			  sockptr_t req_in, size_t in_len, sockptr_t req_out,
+			  size_t out_len, u64 *tsm_code)
+{
+	struct pci_tsm_pf0 *tsm_pf0;
+	struct pci_tdi *tdi;
+	int rc;
+
+	/* Forbid requests that are not directly related to TDISP operations */
+	if (scope > PCI_TSM_REQ_STATE_CHANGE)
+		return -EINVAL;
+
+	ACQUIRE(rwsem_read_intr, lock)(&pci_tsm_rwsem);
+	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &lock)))
+		return rc;
+
+	if (!pdev->tsm)
+		return -ENXIO;
+
+	if (!is_link_tsm(pdev->tsm->tsm_dev))
+		return -ENXIO;
+
+	tsm_pf0 = to_pci_tsm_pf0(pdev->tsm);
+	ACQUIRE(mutex_intr, ops_lock)(&tsm_pf0->lock);
+	if ((rc = ACQUIRE_ERR(mutex_intr, &ops_lock)))
+		return rc;
+
+	tdi = pdev->tsm->tdi;
+	if (!tdi)
+		return -ENXIO;
+	return to_pci_tsm_ops(pdev->tsm)->guest_req(tdi, scope, req_in, in_len,
+						    req_out, out_len, tsm_code);
+}
+EXPORT_SYMBOL_GPL(pci_tsm_guest_req);
+
 static void pci_tsm_unbind_all(struct pci_dev *pdev)
 {
 	pci_tsm_walk_fns_reverse(pdev, __pci_tsm_unbind, NULL);