--- /dev/null
+#ifndef _IPXE_VMWARE_H
+#define _IPXE_VMWARE_H
+
+/** @file
+ *
+ * VMware backdoor mechanism
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+
+/** VMware backdoor I/O port */
+#define VMW_PORT 0x5658
+
+/** VMware backdoor magic value */
+#define VMW_MAGIC 0x564d5868 /* "VMXh" */
+
+/** VMware backdoor magic instruction */
+#define VMW_BACKDOOR "inl %%dx, %%eax"
+
+/** Get VMware version */
+#define VMW_CMD_GET_VERSION 0x0a
+
+/** Issue GuestRPC command */
+#define VMW_CMD_GUESTRPC 0x1e
+
+/**
+ * Get VMware version
+ *
+ * @ret version VMware version(?)
+ * @ret magic VMware magic number, if present
+ * @ret product_type VMware product type
+ */
+static inline __attribute__ (( always_inline )) void
+vmware_cmd_get_version ( uint32_t *version, uint32_t *magic,
+ uint32_t *product_type ) {
+ uint32_t discard_d;
+
+ /* Perform backdoor call */
+ __asm__ __volatile__ ( VMW_BACKDOOR
+ : "=a" ( *version ), "=b" ( *magic ),
+ "=c" ( *product_type ), "=d" ( discard_d )
+ : "0" ( VMW_MAGIC ), "1" ( 0 ),
+ "2" ( VMW_CMD_GET_VERSION ),
+ "3" ( VMW_PORT ) );
+}
+
+/**
+ * Issue GuestRPC command
+ *
+ * @v channel Channel number
+ * @v subcommand GuestRPC subcommand
+ * @v parameter Subcommand-specific parameter
+ * @ret edxhi Subcommand-specific result
+ * @ret ebx Subcommand-specific result
+ * @ret status Command status
+ */
+static inline __attribute__ (( always_inline )) uint32_t
+vmware_cmd_guestrpc ( int channel, uint16_t subcommand, uint32_t parameter,
+ uint16_t *edxhi, uint32_t *ebx ) {
+ uint32_t discard_a;
+ uint32_t status;
+ uint32_t edx;
+
+ /* Perform backdoor call */
+ __asm__ __volatile__ ( VMW_BACKDOOR
+ : "=a" ( discard_a ), "=b" ( *ebx ),
+ "=c" ( status ), "=d" ( edx )
+ : "0" ( VMW_MAGIC ), "1" ( parameter ),
+ "2" ( VMW_CMD_GUESTRPC | ( subcommand << 16 )),
+ "3" ( VMW_PORT | ( channel << 16 ) ) );
+ *edxhi = ( edx >> 16 );
+
+ return status;
+}
+
+extern int vmware_present ( void );
+
+#endif /* _IPXE_VMWARE_H */