[xen] Add basic support for PV-HVM domains

Add basic support for Xen PV-HVM domains (detected via the Xen
platform PCI device with IDs 5853:0001), including support for
accessing configuration via XenStore and enumerating devices via
XenBus.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 73 insertions, 0 deletions

diff --git a/src/include/ipxe/xen.h b/src/include/ipxe/xen.h
new file mode 100644
index 000000000..546b0c348
--- /dev/null
+++ b/src/include/ipxe/xen.h
@@ -0,0 +1,73 @@
+#ifndef _IPXE_XEN_H
+#define _IPXE_XEN_H
+
+/** @file
+ *
+ * Xen interface
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/* Define Xen interface version before including any Xen header files */
+#define __XEN_INTERFACE_VERSION__ 0x00040400
+
+#include <stdint.h>
+#include <ipxe/uaccess.h>
+#include <xen/xen.h>
+#include <xen/event_channel.h>
+
+/* Memory barrier macros used by ring.h */
+#define xen_mb() mb()
+#define xen_rmb() rmb()
+#define xen_wmb() wmb()
+
+struct xen_hypercall;
+
+/** A Xen grant table */
+struct xen_grant {
+	/** Grant table entries */
+	union grant_entry_v2 *table;
+	/** Number of grant table entries (must be a power of two) */
+	unsigned int count;
+	/** Number of grant table entries in use */
+	unsigned int used;
+	/** Most recently used grant reference */
+	unsigned int ref;
+};
+
+/** A XenStore */
+struct xen_store {
+	/** XenStore domain interface */
+	struct xenstore_domain_interface *intf;
+	/** Event channel */
+	evtchn_port_t port;
+};
+
+/** A Xen hypervisor */
+struct xen_hypervisor {
+	/** Hypercall table */
+	struct xen_hypercall *hypercall;
+	/** Shared info page */
+	struct shared_info *shared;
+	/** Grant table */
+	struct xen_grant grant;
+	/** XenStore */
+	struct xen_store store;
+};
+
+#include <bits/xen.h>
+
+/**
+ * Convert a Xen status code to an iPXE status code
+ *
+ * @v xenrc		Xen status code (negated)
+ * @ret rc		iPXE status code (before negation)
+ *
+ * Xen status codes are defined in the file include/xen/errno.h in the
+ * Xen repository.  They happen to match the Linux error codes, some
+ * of which can be found in our include/ipxe/errno/linux.h.
+ */
+#define EXEN( xenrc ) EPLATFORM ( EINFO_EPLATFORM, -(xenrc) )
+
+#endif /* _IPXE_XEN_H */