diff mbox

[edk2,v3,20/27] Ovmf/Xen: implement XenHypercallLib for ARM

Message ID 1422991212-9257-21-git-send-email-ard.biesheuvel@linaro.org
State New
Headers show

Commit Message

Ard Biesheuvel Feb. 3, 2015, 7:20 p.m. UTC
This patch adds an implementation of XenHypercallLib for both
AArch64 and AArch32 execution modes on ARM systems.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 .../Include/IndustryStandard/Xen/arch-arm/xen.h    | 436 +++++++++++++++++++++
 OvmfPkg/Include/IndustryStandard/Xen/xen.h         |   2 +-
 .../Library/XenHypercallLib/Aarch64/Hypercall.S    |  26 ++
 OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S    |  25 ++
 .../Library/XenHypercallLib/XenHypercallLibArm.inf |  40 ++
 5 files changed, 528 insertions(+), 1 deletion(-)
 create mode 100644 OvmfPkg/Include/IndustryStandard/Xen/arch-arm/xen.h
 create mode 100644 OvmfPkg/Library/XenHypercallLib/Aarch64/Hypercall.S
 create mode 100644 OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S
 create mode 100644 OvmfPkg/Library/XenHypercallLib/XenHypercallLibArm.inf
diff mbox

Patch

diff --git a/OvmfPkg/Include/IndustryStandard/Xen/arch-arm/xen.h b/OvmfPkg/Include/IndustryStandard/Xen/arch-arm/xen.h
new file mode 100644
index 000000000000..655a221f6337
--- /dev/null
+++ b/OvmfPkg/Include/IndustryStandard/Xen/arch-arm/xen.h
@@ -0,0 +1,436 @@ 
+/******************************************************************************
+ * arch-arm.h
+ *
+ * Guest OS interface to ARM Xen.
+ *
+ * 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 2011 (C) Citrix Systems
+ */
+
+#ifndef __XEN_PUBLIC_ARCH_ARM_H__
+#define __XEN_PUBLIC_ARCH_ARM_H__
+
+/*
+ * `incontents 50 arm_abi Hypercall Calling Convention
+ *
+ * A hypercall is issued using the ARM HVC instruction.
+ *
+ * A hypercall can take up to 5 arguments. These are passed in
+ * registers, the first argument in x0/r0 (for arm64/arm32 guests
+ * respectively irrespective of whether the underlying hypervisor is
+ * 32- or 64-bit), the second argument in x1/r1, the third in x2/r2,
+ * the forth in x3/r3 and the fifth in x4/r4.
+ *
+ * The hypercall number is passed in r12 (arm) or x16 (arm64). In both
+ * cases the relevant ARM procedure calling convention specifies this
+ * is an inter-procedure-call scratch register (e.g. for use in linker
+ * stubs). This use does not conflict with use during a hypercall.
+ *
+ * The HVC ISS must contain a Xen specific TAG: XEN_HYPERCALL_TAG.
+ *
+ * The return value is in x0/r0.
+ *
+ * The hypercall will clobber x16/r12 and the argument registers used
+ * by that hypercall (except r0 which is the return value) i.e. in
+ * addition to x16/r12 a 2 argument hypercall will clobber x1/r1 and a
+ * 4 argument hypercall will clobber x1/r1, x2/r2 and x3/r3.
+ *
+ * Parameter structs passed to hypercalls are laid out according to
+ * the Procedure Call Standard for the ARM Architecture (AAPCS, AKA
+ * EABI) and Procedure Call Standard for the ARM 64-bit Architecture
+ * (AAPCS64). Where there is a conflict the 64-bit standard should be
+ * used regardless of guest type. Structures which are passed as
+ * hypercall arguments are always little endian.
+ *
+ * All memory which is shared with other entities in the system
+ * (including the hypervisor and other guests) must reside in memory
+ * which is mapped as Normal Inner-cacheable. This applies to:
+ *  - hypercall arguments passed via a pointer to guest memory.
+ *  - memory shared via the grant table mechanism (including PV I/O
+ *    rings etc).
+ *  - memory shared with the hypervisor (struct shared_info, struct
+ *    vcpu_info, the grant table, etc).
+ *
+ * Any Inner cache allocation strategy (Write-Back, Write-Through etc)
+ * is acceptable. There is no restriction on the Outer-cacheability.
+ */
+
+/*
+ * `incontents 55 arm_hcall Supported Hypercalls
+ *
+ * Xen on ARM makes extensive use of hardware facilities and therefore
+ * only a subset of the potential hypercalls are required.
+ *
+ * Since ARM uses second stage paging any machine/physical addresses
+ * passed to hypercalls are Guest Physical Addresses (Intermediate
+ * Physical Addresses) unless otherwise noted.
+ *
+ * The following hypercalls (and sub operations) are supported on the
+ * ARM platform. Other hypercalls should be considered
+ * unavailable/unsupported.
+ *
+ *  HYPERVISOR_memory_op
+ *   All generic sub-operations.
+ *
+ *   In addition the following arch specific sub-ops:
+ *    * XENMEM_add_to_physmap
+ *    * XENMEM_add_to_physmap_batch
+ *
+ *  HYPERVISOR_domctl
+ *   All generic sub-operations, with the exception of:
+ *    * XEN_DOMCTL_iomem_permission (not yet implemented)
+ *    * XEN_DOMCTL_irq_permission (not yet implemented)
+ *
+ *  HYPERVISOR_sched_op
+ *   All generic sub-operations, with the exception of:
+ *    * SCHEDOP_block -- prefer wfi hardware instruction
+ *
+ *  HYPERVISOR_console_io
+ *   All generic sub-operations
+ *
+ *  HYPERVISOR_xen_version
+ *   All generic sub-operations
+ *
+ *  HYPERVISOR_event_channel_op
+ *   All generic sub-operations
+ *
+ *  HYPERVISOR_physdev_op
+ *   No sub-operations are currenty supported
+ *
+ *  HYPERVISOR_sysctl
+ *   All generic sub-operations, with the exception of:
+ *    * XEN_SYSCTL_page_offline_op
+ *    * XEN_SYSCTL_get_pmstat
+ *    * XEN_SYSCTL_pm_op
+ *
+ *  HYPERVISOR_hvm_op
+ *   Exactly these sub-operations are supported:
+ *    * HVMOP_set_param
+ *    * HVMOP_get_param
+ *
+ *  HYPERVISOR_grant_table_op
+ *   All generic sub-operations
+ *
+ *  HYPERVISOR_vcpu_op
+ *   Exactly these sub-operations are supported:
+ *    * VCPUOP_register_vcpu_info
+ *    * VCPUOP_register_runstate_memory_area
+ *
+ *
+ * Other notes on the ARM ABI:
+ *
+ * - struct start_info is not exported to ARM guests.
+ *
+ * - struct shared_info is mapped by ARM guests using the
+ *   HYPERVISOR_memory_op sub-op XENMEM_add_to_physmap, passing
+ *   XENMAPSPACE_shared_info as space parameter.
+ *
+ * - All the per-cpu struct vcpu_info are mapped by ARM guests using the
+ *   HYPERVISOR_vcpu_op sub-op VCPUOP_register_vcpu_info, including cpu0
+ *   struct vcpu_info.
+ *
+ * - The grant table is mapped using the HYPERVISOR_memory_op sub-op
+ *   XENMEM_add_to_physmap, passing XENMAPSPACE_grant_table as space
+ *   parameter. The memory range specified under the Xen compatible
+ *   hypervisor node on device tree can be used as target gpfn for the
+ *   mapping.
+ *
+ * - Xenstore is initialized by using the two hvm_params
+ *   HVM_PARAM_STORE_PFN and HVM_PARAM_STORE_EVTCHN. They can be read
+ *   with the HYPERVISOR_hvm_op sub-op HVMOP_get_param.
+ *
+ * - The paravirtualized console is initialized by using the two
+ *   hvm_params HVM_PARAM_CONSOLE_PFN and HVM_PARAM_CONSOLE_EVTCHN. They
+ *   can be read with the HYPERVISOR_hvm_op sub-op HVMOP_get_param.
+ *
+ * - Event channel notifications are delivered using the percpu GIC
+ *   interrupt specified under the Xen compatible hypervisor node on
+ *   device tree.
+ *
+ * - The device tree Xen compatible node is fully described under Linux
+ *   at Documentation/devicetree/bindings/arm/xen.txt.
+ */
+
+#define XEN_HYPERCALL_TAG   0XEA1
+
+#define uint64_aligned_t UINT64 __attribute__((aligned(8)))
+
+#ifndef __ASSEMBLY__
+#define ___DEFINE_XEN_GUEST_HANDLE(name, type)                  \
+    typedef union { type *p; unsigned long q; }                 \
+        __guest_handle_ ## name;                                \
+    typedef union { type *p; uint64_aligned_t q; }              \
+        __guest_handle_64_ ## name;
+
+/*
+ * XEN_GUEST_HANDLE represents a guest pointer, when passed as a field
+ * in a struct in memory. On ARM is always 8 bytes sizes and 8 bytes
+ * aligned.
+ * XEN_GUEST_HANDLE_PARAM represent a guest pointer, when passed as an
+ * hypercall argument. It is 4 bytes on aarch and 8 bytes on aarch64.
+ */
+#define __DEFINE_XEN_GUEST_HANDLE(name, type) \
+    ___DEFINE_XEN_GUEST_HANDLE(name, type);   \
+    ___DEFINE_XEN_GUEST_HANDLE(const_##name, const type)
+#define DEFINE_XEN_GUEST_HANDLE(name)   __DEFINE_XEN_GUEST_HANDLE(name, name)
+#define __XEN_GUEST_HANDLE(name)        __guest_handle_64_ ## name
+#define XEN_GUEST_HANDLE(name)          __XEN_GUEST_HANDLE(name)
+/* this is going to be changed on 64 bit */
+#define XEN_GUEST_HANDLE_PARAM(name)    __guest_handle_ ## name
+#define set_xen_guest_handle_raw(hnd, val)                  \
+    do {                                                    \
+        typeof(&(hnd)) _sxghr_tmp = &(hnd);                 \
+        _sxghr_tmp->q = 0;                                  \
+        _sxghr_tmp->p = val;                                \
+    } while ( 0 )
+#ifdef __XEN_TOOLS__
+#define get_xen_guest_handle(val, hnd)  do { val = (hnd).p; } while (0)
+#endif
+#define set_xen_guest_handle(hnd, val) set_xen_guest_handle_raw(hnd, val)
+
+#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
+/* Anonymous union includes both 32- and 64-bit names (e.g., r0/x0). */
+# define __DECL_REG(n64, n32) union {          \
+        UINT64 n64;                          \
+        UINT32 n32;                          \
+    }
+#else
+/* Non-gcc sources must always use the proper 64-bit name (e.g., x0). */
+#define __DECL_REG(n64, n32) UINT64 n64
+#endif
+
+struct vcpu_guest_core_regs
+{
+    /*         Aarch64       Aarch32 */
+    __DECL_REG(x0,           r0_usr);
+    __DECL_REG(x1,           r1_usr);
+    __DECL_REG(x2,           r2_usr);
+    __DECL_REG(x3,           r3_usr);
+    __DECL_REG(x4,           r4_usr);
+    __DECL_REG(x5,           r5_usr);
+    __DECL_REG(x6,           r6_usr);
+    __DECL_REG(x7,           r7_usr);
+    __DECL_REG(x8,           r8_usr);
+    __DECL_REG(x9,           r9_usr);
+    __DECL_REG(x10,          r10_usr);
+    __DECL_REG(x11,          r11_usr);
+    __DECL_REG(x12,          r12_usr);
+
+    __DECL_REG(x13,          sp_usr);
+    __DECL_REG(x14,          lr_usr);
+
+    __DECL_REG(x15,          __unused_sp_hyp);
+
+    __DECL_REG(x16,          lr_irq);
+    __DECL_REG(x17,          sp_irq);
+
+    __DECL_REG(x18,          lr_svc);
+    __DECL_REG(x19,          sp_svc);
+
+    __DECL_REG(x20,          lr_abt);
+    __DECL_REG(x21,          sp_abt);
+
+    __DECL_REG(x22,          lr_und);
+    __DECL_REG(x23,          sp_und);
+
+    __DECL_REG(x24,          r8_fiq);
+    __DECL_REG(x25,          r9_fiq);
+    __DECL_REG(x26,          r10_fiq);
+    __DECL_REG(x27,          r11_fiq);
+    __DECL_REG(x28,          r12_fiq);
+
+    __DECL_REG(x29,          sp_fiq);
+    __DECL_REG(x30,          lr_fiq);
+
+    /* Return address and mode */
+    __DECL_REG(pc64,         pc32);             /* ELR_EL2 */
+    UINT32 cpsr;                              /* SPSR_EL2 */
+
+    union {
+        UINT32 spsr_el1;       /* AArch64 */
+        UINT32 spsr_svc;       /* AArch32 */
+    };
+
+    /* AArch32 guests only */
+    UINT32 spsr_fiq, spsr_irq, spsr_und, spsr_abt;
+
+    /* AArch64 guests only */
+    UINT64 sp_el0;
+    UINT64 sp_el1, elr_el1;
+};
+typedef struct vcpu_guest_core_regs vcpu_guest_core_regs_t;
+DEFINE_XEN_GUEST_HANDLE(vcpu_guest_core_regs_t);
+
+#undef __DECL_REG
+
+typedef UINT64 xen_pfn_t;
+#define PRI_xen_pfn PRIx64
+
+/* Maximum number of virtual CPUs in legacy multi-processor guests. */
+/* Only one. All other VCPUS must use VCPUOP_register_vcpu_info */
+#define XEN_LEGACY_MAX_VCPUS 1
+
+typedef UINT64 xen_ulong_t;
+#define PRI_xen_ulong PRIx64
+
+#if defined(__XEN__) || defined(__XEN_TOOLS__)
+struct vcpu_guest_context {
+#define _VGCF_online                   0
+#define VGCF_online                    (1<<_VGCF_online)
+    UINT32 flags;                         /* VGCF_* */
+
+    struct vcpu_guest_core_regs user_regs;  /* Core CPU registers */
+
+    UINT32 sctlr;
+    UINT64 ttbcr, ttbr0, ttbr1;
+};
+typedef struct vcpu_guest_context vcpu_guest_context_t;
+DEFINE_XEN_GUEST_HANDLE(vcpu_guest_context_t);
+#endif
+
+struct arch_vcpu_info {
+};
+typedef struct arch_vcpu_info arch_vcpu_info_t;
+
+struct arch_shared_info {
+};
+typedef struct arch_shared_info arch_shared_info_t;
+typedef UINT64 xen_callback_t;
+
+#endif
+
+#if defined(__XEN__) || defined(__XEN_TOOLS__)
+
+/* PSR bits (CPSR, SPSR)*/
+
+#define PSR_THUMB       (1<<5)        /* Thumb Mode enable */
+#define PSR_FIQ_MASK    (1<<6)        /* Fast Interrupt mask */
+#define PSR_IRQ_MASK    (1<<7)        /* Interrupt mask */
+#define PSR_ABT_MASK    (1<<8)        /* Asynchronous Abort mask */
+#define PSR_BIG_ENDIAN  (1<<9)        /* arm32: Big Endian Mode */
+#define PSR_DBG_MASK    (1<<9)        /* arm64: Debug Exception mask */
+#define PSR_IT_MASK     (0x0600fc00)  /* Thumb If-Then Mask */
+#define PSR_JAZELLE     (1<<24)       /* Jazelle Mode */
+
+/* 32 bit modes */
+#define PSR_MODE_USR 0x10
+#define PSR_MODE_FIQ 0x11
+#define PSR_MODE_IRQ 0x12
+#define PSR_MODE_SVC 0x13
+#define PSR_MODE_MON 0x16
+#define PSR_MODE_ABT 0x17
+#define PSR_MODE_HYP 0x1a
+#define PSR_MODE_UND 0x1b
+#define PSR_MODE_SYS 0x1f
+
+/* 64 bit modes */
+#define PSR_MODE_BIT  0x10 /* Set iff AArch32 */
+#define PSR_MODE_EL3h 0x0d
+#define PSR_MODE_EL3t 0x0c
+#define PSR_MODE_EL2h 0x09
+#define PSR_MODE_EL2t 0x08
+#define PSR_MODE_EL1h 0x05
+#define PSR_MODE_EL1t 0x04
+#define PSR_MODE_EL0t 0x00
+
+#define PSR_GUEST32_INIT  (PSR_ABT_MASK|PSR_FIQ_MASK|PSR_IRQ_MASK|PSR_MODE_SVC)
+#define PSR_GUEST64_INIT (PSR_ABT_MASK|PSR_FIQ_MASK|PSR_IRQ_MASK|PSR_MODE_EL1h)
+
+#define SCTLR_GUEST_INIT    0x00c50078
+
+/*
+ * Virtual machine platform (memory layout, interrupts)
+ *
+ * These are defined for consistency between the tools and the
+ * hypervisor. Guests must not rely on these hardcoded values but
+ * should instead use the FDT.
+ */
+
+/* Physical Address Space */
+
+/* vGIC mappings: Only one set of mapping is used by the guest.
+ * Therefore they can overlap.
+ */
+
+/* vGIC v2 mappings */
+#define GUEST_GICD_BASE   0x03001000ULL
+#define GUEST_GICD_SIZE   0x00001000ULL
+#define GUEST_GICC_BASE   0x03002000ULL
+#define GUEST_GICC_SIZE   0x00000100ULL
+
+/* vGIC v3 mappings */
+#define GUEST_GICV3_GICD_BASE      0x03001000ULL
+#define GUEST_GICV3_GICD_SIZE      0x00010000ULL
+
+#define GUEST_GICV3_RDIST_STRIDE   0x20000ULL
+#define GUEST_GICV3_RDIST_REGIONS  1
+
+#define GUEST_GICV3_GICR0_BASE     0x03020000ULL    /* vCPU0 - vCPU7 */
+#define GUEST_GICV3_GICR0_SIZE     0x00100000ULL
+
+/* 16MB == 4096 pages reserved for guest to use as a region to map its
+ * grant table in.
+ */
+#define GUEST_GNTTAB_BASE 0x38000000ULL
+#define GUEST_GNTTAB_SIZE 0x01000000ULL
+
+#define GUEST_MAGIC_BASE  0x39000000ULL
+#define GUEST_MAGIC_SIZE  0x01000000ULL
+
+#define GUEST_RAM_BANKS   2
+
+#define GUEST_RAM0_BASE   0x40000000ULL /* 3GB of low RAM @ 1GB */
+#define GUEST_RAM0_SIZE   0xc0000000ULL
+
+#define GUEST_RAM1_BASE   0x0200000000ULL /* 1016GB of RAM @ 8GB */
+#define GUEST_RAM1_SIZE   0xfe00000000ULL
+
+#define GUEST_RAM_BASE    GUEST_RAM0_BASE /* Lowest RAM address */
+/* Largest amount of actual RAM, not including holes */
+#define GUEST_RAM_MAX     (GUEST_RAM0_SIZE + GUEST_RAM1_SIZE)
+/* Suitable for e.g. const uint64_t ramfoo[] = GUEST_RAM_BANK_FOOS; */
+#define GUEST_RAM_BANK_BASES   { GUEST_RAM0_BASE, GUEST_RAM1_BASE }
+#define GUEST_RAM_BANK_SIZES   { GUEST_RAM0_SIZE, GUEST_RAM1_SIZE }
+
+/* Interrupts */
+#define GUEST_TIMER_VIRT_PPI    27
+#define GUEST_TIMER_PHYS_S_PPI  29
+#define GUEST_TIMER_PHYS_NS_PPI 30
+#define GUEST_EVTCHN_PPI        31
+
+/* PSCI functions */
+#define PSCI_cpu_suspend 0
+#define PSCI_cpu_off     1
+#define PSCI_cpu_on      2
+#define PSCI_migrate     3
+
+#endif
+
+#endif /*  __XEN_PUBLIC_ARCH_ARM_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/OvmfPkg/Include/IndustryStandard/Xen/xen.h b/OvmfPkg/Include/IndustryStandard/Xen/xen.h
index 1cd7ab3ab136..8596ca1bd26f 100644
--- a/OvmfPkg/Include/IndustryStandard/Xen/xen.h
+++ b/OvmfPkg/Include/IndustryStandard/Xen/xen.h
@@ -37,7 +37,7 @@ 
 #if defined(MDE_CPU_IA32) || defined(MDE_CPU_X64)
 #include "arch-x86/xen.h"
 #elif defined(__arm__) || defined (__aarch64__)
-#include "arch-arm.h"
+#include "arch-arm/xen.h"
 #else
 #error "Unsupported architecture"
 #endif
diff --git a/OvmfPkg/Library/XenHypercallLib/Aarch64/Hypercall.S b/OvmfPkg/Library/XenHypercallLib/Aarch64/Hypercall.S
new file mode 100644
index 000000000000..b1b5d4cc3f28
--- /dev/null
+++ b/OvmfPkg/Library/XenHypercallLib/Aarch64/Hypercall.S
@@ -0,0 +1,26 @@ 
+
+/** @file
+  AArch64 implementation of XenHypercall2
+
+  Copyright (C) 2014, Linaro Ltd.
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <IndustryStandard/Xen/arch-arm/xen.h>
+
+  .text
+  .global   ASM_PFX(XenHypercall2)
+ASM_PFX(XenHypercall2):
+  mov     x16, x0
+  mov     x0, x1
+  mov     x1, x2
+  hvc     #XEN_HYPERCALL_TAG
+  ret
diff --git a/OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S b/OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S
new file mode 100644
index 000000000000..b38e1a8f18da
--- /dev/null
+++ b/OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S
@@ -0,0 +1,25 @@ 
+/** @file
+  ARM (AArch32) implementation of XenHypercall2
+
+  Copyright (C) 2014, Linaro Ltd.
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <IndustryStandard/Xen/arch-arm/xen.h>
+
+  .text
+  .global   ASM_PFX(XenHypercall2)
+ASM_PFX(XenHypercall2):
+  mov     r12, r0
+  mov     r0, r1
+  mov     r1, r2
+  hvc     #XEN_HYPERCALL_TAG
+  bx      lr
diff --git a/OvmfPkg/Library/XenHypercallLib/XenHypercallLibArm.inf b/OvmfPkg/Library/XenHypercallLib/XenHypercallLibArm.inf
new file mode 100644
index 000000000000..9cbbeb5d8789
--- /dev/null
+++ b/OvmfPkg/Library/XenHypercallLib/XenHypercallLibArm.inf
@@ -0,0 +1,40 @@ 
+## @file
+#  Xen Hypercall abstraction lib for ARM architecture
+#
+#  Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR>
+#  This program and the accompanying materials
+#  are licensed and made available under the terms and conditions of the BSD License
+#  which accompanies this distribution.  The full text of the license may be found at
+#  http://opensource.org/licenses/bsd-license.php
+#
+#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = XenHypercallLibArm
+  FILE_GUID                      = 9607AC2E-FCB9-499B-9475-612282019568
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = XenHypercallLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = ARM AARCH64
+#
+
+[Sources.ARM]
+  Arm/Hypercall.S
+
+[Sources.AARCH64]
+  Aarch64/Hypercall.S
+
+[Sources]
+  XenHypercall.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec