[PATCH v4 04/15] x86/tdx: Add helper to do MapGPA hypercall

@@ -56,6 +56,15 @@ struct ve_info {
 	u32 instr_info;
 };
 
+/*
+ * Page mapping type enum. This is software construct not
+ * part of any hardware or VMM ABI.
+ */
+enum tdx_map_type {
+	TDX_MAP_PRIVATE,
+	TDX_MAP_SHARED,
+};
+
 #ifdef CONFIG_INTEL_TDX_GUEST
 
 void __init tdx_early_init(void);

@@ -79,6 +88,9 @@ bool tdg_early_handle_ve(struct pt_regs *regs);
 
 extern phys_addr_t tdg_shared_mask(void);
 
+extern int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,
+				enum tdx_map_type map_type);
+
 /*
  * To support I/O port access in decompressor or early kernel init
  * code, since #VE exception handler cannot be used, use paravirt

@@ -149,6 +161,12 @@ static inline bool tdg_early_handle_ve(struct pt_regs *regs) { return false; }
 
 static inline phys_addr_t tdg_shared_mask(void) { return 0; }
 
+static inline int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,
+				       enum tdx_map_type map_type)
+{
+	return -ENODEV;
+}
+
 #endif /* CONFIG_INTEL_TDX_GUEST */
 
 #ifdef CONFIG_INTEL_TDX_GUEST_KVM

@@ -18,6 +18,9 @@
 #define TDINFO				1
 #define TDGETVEINFO			3
 
+/* TDX hypercall Leaf IDs */
+#define TDVMCALL_MAP_GPA		0x10001
+
 #define VE_IS_IO_OUT(exit_qual)		(((exit_qual) & 8) ? 0 : 1)
 #define VE_GET_IO_SIZE(exit_qual)	(((exit_qual) & 7) + 1)
 #define VE_GET_PORT_NUM(exit_qual)	((exit_qual) >> 16)

@@ -97,6 +100,28 @@ static void tdg_get_info(void)
 	physical_mask &= ~tdg_shared_mask();
 }
 
+/*
+ * Inform the VMM of the guest's intent for this physical page:
+ * shared with the VMM or private to the guest.  The VMM is
+ * expected to change its mapping of the page in response.
+ *
+ * Note: shared->private conversions require further guest
+ * action to accept the page.
+ */
+int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,
+			 enum tdx_map_type map_type)
+{
+	u64 ret;
+
+	if (map_type == TDX_MAP_SHARED)
+		gpa |= tdg_shared_mask();
+
+	ret = _tdx_hypercall(TDVMCALL_MAP_GPA, gpa, PAGE_SIZE * numpages, 0, 0,
+			     NULL);
+
+	return ret ? -EIO : 0;
+}
+
 static __cpuidle void tdg_halt(void)
 {
 	u64 ret;