x86/pconfig: Provide defines and helper to run MKTME_KEY_PROG leaf

MKTME_KEY_PROG allows to manipulate MKTME keys in the CPU.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kai Huang <kai.huang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180305162610.37510-6-kirill.shutemov@linux.intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/intel_pconfig.h

@@ -12,4 +12,54 @@ enum pconfig_target {
 
 int pconfig_target_supported(enum pconfig_target target);
 
+enum pconfig_leaf {
+	MKTME_KEY_PROGRAM	= 0,
+	PCONFIG_LEAF_INVALID,
+};
+
+#define PCONFIG ".byte 0x0f, 0x01, 0xc5"
+
+/* Defines and structure for MKTME_KEY_PROGRAM of PCONFIG instruction */
+
+/* mktme_key_program::keyid_ctrl COMMAND, bits [7:0] */
+#define MKTME_KEYID_SET_KEY_DIRECT	0
+#define MKTME_KEYID_SET_KEY_RANDOM	1
+#define MKTME_KEYID_CLEAR_KEY		2
+#define MKTME_KEYID_NO_ENCRYPT		3
+
+/* mktme_key_program::keyid_ctrl ENC_ALG, bits [23:8] */
+#define MKTME_AES_XTS_128	(1 << 8)
+
+/* Return codes from the PCONFIG MKTME_KEY_PROGRAM */
+#define MKTME_PROG_SUCCESS	0
+#define MKTME_INVALID_PROG_CMD	1
+#define MKTME_ENTROPY_ERROR	2
+#define MKTME_INVALID_KEYID	3
+#define MKTME_INVALID_ENC_ALG	4
+#define MKTME_DEVICE_BUSY	5
+
+/* Hardware requires the structure to be 256 byte alinged. Otherwise #GP(0). */
+struct mktme_key_program {
+	u16 keyid;
+	u32 keyid_ctrl;
+	u8 __rsvd[58];
+	u8 key_field_1[64];
+	u8 key_field_2[64];
+} __packed __aligned(256);
+
+static inline int mktme_key_program(struct mktme_key_program *key_program)
+{
+	unsigned long rax = MKTME_KEY_PROGRAM;
+
+	if (!pconfig_target_supported(MKTME_TARGET))
+		return -ENXIO;
+
+	asm volatile(PCONFIG
+		: "=a" (rax), "=b" (key_program)
+		: "0" (rax), "1" (key_program)
+		: "memory", "cc");
+
+	return rax;
+}
+
 #endif	/* _ASM_X86_INTEL_PCONFIG_H */