diff --git a/include/xen/interface/elfnote.h b/include/xen/interface/elfnote.h
index f90b034..9e9f9bf 100644
--- a/include/xen/interface/elfnote.h
+++ b/include/xen/interface/elfnote.h
@@ -193,9 +193,19 @@
 #define XEN_ELFNOTE_SUPPORTED_FEATURES 17
 
 /*
+ * Physical entry point into the kernel.
+ *
+ * 32bit entry point into the kernel. When requested to launch the
+ * guest kernel in a HVM container, Xen will use this entry point to
+ * launch the guest in 32bit protected mode with paging disabled.
+ * Ignored otherwise.
+ */
+#define XEN_ELFNOTE_PHYS32_ENTRY 18
+
+/*
  * The number of the highest elfnote defined.
  */
-#define XEN_ELFNOTE_MAX XEN_ELFNOTE_SUPPORTED_FEATURES
+#define XEN_ELFNOTE_MAX XEN_ELFNOTE_PHYS32_ENTRY
 
 #endif /* __XEN_PUBLIC_ELFNOTE_H__ */
 
diff --git a/include/xen/interface/hvm/hvm_vcpu.h b/include/xen/interface/hvm/hvm_vcpu.h
new file mode 100644
index 0000000..32ca83e
--- /dev/null
+++ b/include/xen/interface/hvm/hvm_vcpu.h
@@ -0,0 +1,143 @@
+/*
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Copyright (c) 2015, Roger Pau Monne <roger.pau@citrix.com>
+ */
+
+#ifndef __XEN_PUBLIC_HVM_HVM_VCPU_H__
+#define __XEN_PUBLIC_HVM_HVM_VCPU_H__
+
+#include "../xen.h"
+
+struct vcpu_hvm_x86_32 {
+    uint32_t eax;
+    uint32_t ecx;
+    uint32_t edx;
+    uint32_t ebx;
+    uint32_t esp;
+    uint32_t ebp;
+    uint32_t esi;
+    uint32_t edi;
+    uint32_t eip;
+    uint32_t eflags;
+
+    uint32_t cr0;
+    uint32_t cr3;
+    uint32_t cr4;
+
+    uint32_t pad1;
+
+    /*
+     * EFER should only be used to set the NXE bit (if required)
+     * when starting a vCPU in 32bit mode with paging enabled or
+     * to set the LME/LMA bits in order to start the vCPU in
+     * compatibility mode.
+     */
+    uint64_t efer;
+
+    uint32_t cs_base;
+    uint32_t ds_base;
+    uint32_t ss_base;
+    uint32_t es_base;
+    uint32_t tr_base;
+    uint32_t cs_limit;
+    uint32_t ds_limit;
+    uint32_t ss_limit;
+    uint32_t es_limit;
+    uint32_t tr_limit;
+    uint16_t cs_ar;
+    uint16_t ds_ar;
+    uint16_t ss_ar;
+    uint16_t es_ar;
+    uint16_t tr_ar;
+
+    uint16_t pad2[3];
+};
+
+/*
+ * The layout of the _ar fields of the segment registers is the
+ * following:
+ *
+ * Bits   [0,3]: type (bits 40-43).
+ * Bit        4: s    (descriptor type, bit 44).
+ * Bit    [5,6]: dpl  (descriptor privilege level, bits 45-46).
+ * Bit        7: p    (segment-present, bit 47).
+ * Bit        8: avl  (available for system software, bit 52).
+ * Bit        9: l    (64-bit code segment, bit 53).
+ * Bit       10: db   (meaning depends on the segment, bit 54).
+ * Bit       11: g    (granularity, bit 55)
+ * Bits [12,15]: unused, must be blank.
+ *
+ * A more complete description of the meaning of this fields can be
+ * obtained from the Intel SDM, Volume 3, section 3.4.5.
+ */
+
+struct vcpu_hvm_x86_64 {
+    uint64_t rax;
+    uint64_t rcx;
+    uint64_t rdx;
+    uint64_t rbx;
+    uint64_t rsp;
+    uint64_t rbp;
+    uint64_t rsi;
+    uint64_t rdi;
+    uint64_t rip;
+    uint64_t rflags;
+
+    uint64_t cr0;
+    uint64_t cr3;
+    uint64_t cr4;
+    uint64_t efer;
+
+    /*
+     * Using VCPU_HVM_MODE_64B implies that the vCPU is launched
+     * directly in long mode, so the cached parts of the segment
+     * registers get set to match that environment.
+     *
+     * If the user wants to launch the vCPU in compatibility mode
+     * the 32-bit structure should be used instead.
+     */
+};
+
+struct vcpu_hvm_context {
+#define VCPU_HVM_MODE_32B 0  /* 32bit fields of the structure will be used. */
+#define VCPU_HVM_MODE_64B 1  /* 64bit fields of the structure will be used. */
+    uint32_t mode;
+
+    uint32_t pad;
+
+    /* CPU registers. */
+    union {
+        struct vcpu_hvm_x86_32 x86_32;
+        struct vcpu_hvm_x86_64 x86_64;
+    } cpu_regs;
+};
+typedef struct vcpu_hvm_context vcpu_hvm_context_t;
+
+#endif /* __XEN_PUBLIC_HVM_HVM_VCPU_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index d133112..61a25c4 100644
--- a/include/xen/interface/xen.h
+++ b/include/xen/interface/xen.h
@@ -645,6 +645,30 @@ struct start_info {
 	unsigned long nr_p2m_frames;/* # of pfns forming initial P->M table.  */
 };
 
+/*
+ * Start of day structure passed to PVH guests in %ebx.
+ *
+ * NOTE: nothing will be loaded at physical address 0, so
+ * a 0 value in any of the address fields should be treated
+ * as not present.
+ */
+struct hvm_start_info {
+#define HVM_START_MAGIC_VALUE 0x336ec578
+    uint32_t magic;             /* Contains the magic value 0x336ec578       */
+                                /* ("xEn3" with the 0x80 bit of the "E" set).*/
+    uint32_t flags;             /* SIF_xxx flags.                            */
+    uint32_t cmdline_paddr;     /* Physical address of the command line.     */
+    uint32_t nr_modules;        /* Number of modules passed to the kernel.   */
+    uint32_t modlist_paddr;     /* Physical address of an array of           */
+                                /* hvm_modlist_entry.                        */
+};
+
+struct hvm_modlist_entry {
+    uint32_t paddr;             /* Physical address of the module.           */
+    uint32_t size;              /* Size of the module in bytes.              */
+};
+
+
 /* These flags are passed in the 'flags' field of start_info_t. */
 #define SIF_PRIVILEGED      (1<<0)  /* Is the domain privileged? */
 #define SIF_INITDOMAIN      (1<<1)  /* Is this the initial control domain? */
