diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index ecfa6822e4d3..5b75067e2745 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -106,6 +106,17 @@ config TEE
 
 source "arch/arm/tee/Kconfig"
 
+config FFA
+	bool "Enable FF-A mediator support" if EXPERT
+	default n
+	depends on ARM_64
+	help
+	  This option enables a minamal FF-A mediator. The mediator is
+	  generic as it follows the FF-A specification [1], but it only
+	  implements a small substet of the specification.
+
+	  [1] https://developer.arm.com/documentation/den0077/latest
+
 endmenu
 
 menu "ARM errata workaround via the alternative framework"
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 1d862351d111..dbf5e593a069 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -20,6 +20,7 @@ obj-y += domain.o
 obj-y += domain_build.init.o
 obj-y += domctl.o
 obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
+obj-$(CONFIG_FFA) += ffa.o
 obj-y += gic.o
 obj-y += gic-v2.o
 obj-$(CONFIG_GICV3) += gic-v3.o
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 8110c1df8638..a93e6a9c4aef 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -27,6 +27,7 @@
 #include <asm/cpufeature.h>
 #include <asm/current.h>
 #include <asm/event.h>
+#include <asm/ffa.h>
 #include <asm/gic.h>
 #include <asm/guest_atomics.h>
 #include <asm/irq.h>
@@ -756,6 +757,9 @@ int arch_domain_create(struct domain *d,
     if ( (rc = tee_domain_init(d, config->arch.tee_type)) != 0 )
         goto fail;
 
+    if ( (rc = ffa_domain_init(d)) != 0 )
+        goto fail;
+
     update_domain_wallclock_time(d);
 
     /*
@@ -998,6 +1002,7 @@ static int relinquish_memory(struct domain *d, struct page_list_head *list)
 enum {
     PROG_pci = 1,
     PROG_tee,
+    PROG_ffa,
     PROG_xen,
     PROG_page,
     PROG_mapping,
@@ -1046,6 +1051,11 @@ int domain_relinquish_resources(struct domain *d)
         if (ret )
             return ret;
 
+    PROGRESS(ffa):
+        ret = ffa_relinquish_resources(d);
+        if (ret )
+            return ret;
+
     PROGRESS(xen):
         ret = relinquish_memory(d, &d->xenpage_list);
         if ( ret )
diff --git a/xen/arch/arm/ffa.c b/xen/arch/arm/ffa.c
new file mode 100644
index 000000000000..9063b7f2b59e
--- /dev/null
+++ b/xen/arch/arm/ffa.c
@@ -0,0 +1,1624 @@
+/*
+ * xen/arch/arm/ffa.c
+ *
+ * Arm Firmware Framework for ARMv8-A(FFA) mediator
+ *
+ * Copyright (C) 2021  Linaro Limited
+ *
+ * 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.
+ */
+
+#include <xen/domain_page.h>
+#include <xen/errno.h>
+#include <xen/init.h>
+#include <xen/lib.h>
+#include <xen/sched.h>
+#include <xen/types.h>
+#include <xen/sizes.h>
+#include <xen/bitops.h>
+
+#include <asm/smccc.h>
+#include <asm/event.h>
+#include <asm/ffa.h>
+#include <asm/regs.h>
+
+/* Error codes */
+#define FFA_RET_OK			0
+#define FFA_RET_NOT_SUPPORTED		-1
+#define FFA_RET_INVALID_PARAMETERS	-2
+#define FFA_RET_NO_MEMORY		-3
+#define FFA_RET_BUSY			-4
+#define FFA_RET_INTERRUPTED		-5
+#define FFA_RET_DENIED			-6
+#define FFA_RET_RETRY			-7
+#define FFA_RET_ABORTED			-8
+
+/* FFA_VERSION helpers */
+#define FFA_VERSION_MAJOR		_AC(1,U)
+#define FFA_VERSION_MAJOR_SHIFT		_AC(16,U)
+#define FFA_VERSION_MAJOR_MASK		_AC(0x7FFF,U)
+#define FFA_VERSION_MINOR		_AC(1,U)
+#define FFA_VERSION_MINOR_SHIFT		_AC(0,U)
+#define FFA_VERSION_MINOR_MASK		_AC(0xFFFF,U)
+#define MAKE_FFA_VERSION(major, minor)	\
+	((((major) & FFA_VERSION_MAJOR_MASK) << FFA_VERSION_MAJOR_SHIFT) | \
+	 ((minor) & FFA_VERSION_MINOR_MASK))
+
+#define FFA_MIN_VERSION		MAKE_FFA_VERSION(1, 0)
+#define FFA_VERSION_1_0		MAKE_FFA_VERSION(1, 0)
+#define FFA_VERSION_1_1		MAKE_FFA_VERSION(1, 1)
+#define FFA_MY_VERSION		MAKE_FFA_VERSION(FFA_VERSION_MAJOR, \
+						 FFA_VERSION_MINOR)
+
+
+#define FFA_HANDLE_HYP_FLAG             BIT(63,ULL)
+
+/* Memory attributes: Normal memory, Write-Back cacheable, Inner shareable */
+#define FFA_NORMAL_MEM_REG_ATTR		_AC(0x2f,U)
+
+/* Memory access permissions: Read-write */
+#define FFA_MEM_ACC_RW			_AC(0x2,U)
+
+/* Clear memory before mapping in receiver */
+#define FFA_MEMORY_REGION_FLAG_CLEAR		BIT(0, U)
+/* Relayer may time slice this operation */
+#define FFA_MEMORY_REGION_FLAG_TIME_SLICE	BIT(1, U)
+/* Clear memory after receiver relinquishes it */
+#define FFA_MEMORY_REGION_FLAG_CLEAR_RELINQUISH	BIT(2, U)
+
+/* Share memory transaction */
+#define FFA_MEMORY_REGION_TRANSACTION_TYPE_SHARE (_AC(1,U) << 3)
+/* Relayer must choose the alignment boundary */
+#define FFA_MEMORY_REGION_FLAG_ANY_ALIGNMENT	_AC(0,U)
+
+#define FFA_HANDLE_INVALID		_AC(0xffffffffffffffff,ULL)
+
+/* Framework direct request/response */
+#define FFA_MSG_FLAG_FRAMEWORK		BIT(31, U)
+#define FFA_MSG_TYPE_MASK		_AC(0xFF,U);
+#define FFA_MSG_PSCI			_AC(0x0,U)
+#define FFA_MSG_SEND_VM_CREATED		_AC(0x4,U)
+#define FFA_MSG_RESP_VM_CREATED		_AC(0x5,U)
+#define FFA_MSG_SEND_VM_DESTROYED	_AC(0x6,U)
+#define FFA_MSG_RESP_VM_DESTROYED	_AC(0x7,U)
+
+/*
+ * Flags used for the FFA_PARTITION_INFO_GET return message:
+ * BIT(0): Supports receipt of direct requests
+ * BIT(1): Can send direct requests
+ * BIT(2): Can send and receive indirect messages
+ * BIT(3): Supports receipt of notifications
+ * BIT(4-5): Partition ID is a PE endpoint ID
+ */
+#define FFA_PART_PROP_DIRECT_REQ_RECV   BIT(0,U)
+#define FFA_PART_PROP_DIRECT_REQ_SEND   BIT(1,U)
+#define FFA_PART_PROP_INDIRECT_MSGS     BIT(2,U)
+#define FFA_PART_PROP_RECV_NOTIF        BIT(3,U)
+#define FFA_PART_PROP_IS_PE_ID          (_AC(0,U) << 4)
+#define FFA_PART_PROP_IS_SEPID_INDEP    (_AC(1,U) << 4)
+#define FFA_PART_PROP_IS_SEPID_DEP      (_AC(2,U) << 4)
+#define FFA_PART_PROP_IS_AUX_ID         (_AC(3,U) << 4)
+#define FFA_PART_PROP_NOTIF_CREATED     BIT(6,U)
+#define FFA_PART_PROP_NOTIF_DESTROYED   BIT(7,U)
+#define FFA_PART_PROP_AARCH64_STATE     BIT(8,U)
+
+/* Function IDs */
+#define FFA_ERROR			_AC(0x84000060,U)
+#define FFA_SUCCESS_32			_AC(0x84000061,U)
+#define FFA_SUCCESS_64			_AC(0xC4000061,U)
+#define FFA_INTERRUPT			_AC(0x84000062,U)
+#define FFA_VERSION			_AC(0x84000063,U)
+#define FFA_FEATURES			_AC(0x84000064,U)
+#define FFA_RX_ACQUIRE			_AC(0x84000084,U)
+#define FFA_RX_RELEASE			_AC(0x84000065,U)
+#define FFA_RXTX_MAP_32			_AC(0x84000066,U)
+#define FFA_RXTX_MAP_64			_AC(0xC4000066,U)
+#define FFA_RXTX_UNMAP			_AC(0x84000067,U)
+#define FFA_PARTITION_INFO_GET		_AC(0x84000068,U)
+#define FFA_ID_GET			_AC(0x84000069,U)
+#define FFA_SPM_ID_GET			_AC(0x84000085,U)
+#define FFA_MSG_WAIT			_AC(0x8400006B,U)
+#define FFA_MSG_YIELD			_AC(0x8400006C,U)
+#define FFA_MSG_RUN			_AC(0x8400006D,U)
+#define FFA_MSG_SEND2			_AC(0x84000086,U)
+#define FFA_MSG_SEND_DIRECT_REQ_32	_AC(0x8400006F,U)
+#define FFA_MSG_SEND_DIRECT_REQ_64	_AC(0xC400006F,U)
+#define FFA_MSG_SEND_DIRECT_RESP_32	_AC(0x84000070,U)
+#define FFA_MSG_SEND_DIRECT_RESP_64	_AC(0xC4000070,U)
+#define FFA_MEM_DONATE_32		_AC(0x84000071,U)
+#define FFA_MEM_DONATE_64		_AC(0xC4000071,U)
+#define FFA_MEM_LEND_32			_AC(0x84000072,U)
+#define FFA_MEM_LEND_64			_AC(0xC4000072,U)
+#define FFA_MEM_SHARE_32		_AC(0x84000073,U)
+#define FFA_MEM_SHARE_64		_AC(0xC4000073,U)
+#define FFA_MEM_RETRIEVE_REQ_32		_AC(0x84000074,U)
+#define FFA_MEM_RETRIEVE_REQ_64		_AC(0xC4000074,U)
+#define FFA_MEM_RETRIEVE_RESP		_AC(0x84000075,U)
+#define FFA_MEM_RELINQUISH		_AC(0x84000076,U)
+#define FFA_MEM_RECLAIM			_AC(0x84000077,U)
+#define FFA_MEM_FRAG_RX			_AC(0x8400007A,U)
+#define FFA_MEM_FRAG_TX			_AC(0x8400007B,U)
+#define FFA_MSG_SEND			_AC(0x8400006E,U)
+#define FFA_MSG_POLL			_AC(0x8400006A,U)
+
+/* Partition information descriptor */
+struct ffa_partition_info_1_0 {
+    uint16_t id;
+    uint16_t execution_context;
+    uint32_t partition_properties;
+};
+
+struct ffa_partition_info_1_1 {
+    uint16_t id;
+    uint16_t execution_context;
+    uint32_t partition_properties;
+    uint8_t uuid[16];
+};
+
+/* Constituent memory region descriptor */
+struct ffa_address_range {
+    uint64_t address;
+    uint32_t page_count;
+    uint32_t reserved;
+};
+
+/* Composite memory region descriptor */
+struct ffa_mem_region {
+    uint32_t total_page_count;
+    uint32_t address_range_count;
+    uint64_t reserved;
+    struct ffa_address_range address_range_array[];
+};
+
+/* Memory access permissions descriptor */
+struct ffa_mem_access_perm {
+    uint16_t endpoint_id;
+    uint8_t perm;
+    uint8_t flags;
+};
+
+/* Endpoint memory access descriptor */
+struct ffa_mem_access {
+    struct ffa_mem_access_perm access_perm;
+    uint32_t region_offs;
+    uint64_t reserved;
+};
+
+/* Lend, donate or share memory transaction descriptor */
+struct ffa_mem_transaction_1_0 {
+    uint16_t sender_id;
+    uint8_t mem_reg_attr;
+    uint8_t reserved0;
+    uint32_t flags;
+    uint64_t global_handle;
+    uint64_t tag;
+    uint32_t reserved1;
+    uint32_t mem_access_count;
+    struct ffa_mem_access mem_access_array[];
+};
+
+struct ffa_mem_transaction_1_1 {
+    uint16_t sender_id;
+    uint16_t mem_reg_attr;
+    uint32_t flags;
+    uint64_t global_handle;
+    uint64_t tag;
+    uint32_t mem_access_size;
+    uint32_t mem_access_count;
+    uint32_t mem_access_offs;
+    uint8_t reserved[12];
+};
+
+/*
+ * The parts needed from struct ffa_mem_transaction_1_0 or struct
+ * ffa_mem_transaction_1_1, used to provide an abstraction of difference in
+ * data structures between version 1.0 and 1.1. This is just an internal
+ * interface and can be changed without changing any ABI.
+ */
+struct ffa_mem_transaction_x {
+    uint16_t sender_id;
+    uint8_t mem_reg_attr;
+    uint8_t flags;
+    uint8_t mem_access_size;
+    uint8_t mem_access_count;
+    uint16_t mem_access_offs;
+    uint64_t global_handle;
+    uint64_t tag;
+};
+
+/* Endpoint RX/TX descriptor */
+struct ffa_endpoint_rxtx_descriptor_1_0 {
+    uint16_t sender_id;
+    uint16_t reserved;
+    uint32_t rx_range_count;
+    uint32_t tx_range_count;
+};
+
+struct ffa_endpoint_rxtx_descriptor_1_1 {
+    uint16_t sender_id;
+    uint16_t reserved;
+    uint32_t rx_region_offs;
+    uint32_t tx_region_offs;
+};
+
+struct ffa_ctx {
+    void *rx;
+    void *tx;
+    struct page_info *rx_pg;
+    struct page_info *tx_pg;
+    unsigned int page_count;
+    uint32_t guest_vers;
+    bool tx_is_mine;
+    bool interrupted;
+};
+
+struct ffa_shm_mem {
+    struct list_head list;
+    uint16_t sender_id;
+    uint16_t ep_id;     /* endpoint, the one lending */
+    uint64_t handle;    /* FFA_HANDLE_INVALID if not set yet */
+    unsigned int page_count;
+    struct page_info *pages[];
+};
+
+struct mem_frag_state {
+    struct list_head list;
+    struct ffa_shm_mem *shm;
+    uint32_t range_count;
+    unsigned int current_page_idx;
+    unsigned int frag_offset;
+    unsigned int range_offset;
+    uint8_t *buf;
+    unsigned int buf_size;
+    struct ffa_address_range range;
+};
+
+/*
+ * Our rx/rx buffer shared with the SPMC
+ */
+static uint32_t ffa_version;
+static uint16_t *subsr_vm_created;
+static unsigned int subsr_vm_created_count;
+static uint16_t *subsr_vm_destroyed;
+static unsigned int subsr_vm_destroyed_count;
+static void *ffa_rx;
+static void *ffa_tx;
+static unsigned int ffa_page_count;
+static spinlock_t ffa_buffer_lock = SPIN_LOCK_UNLOCKED;
+
+static struct list_head ffa_mem_list = LIST_HEAD_INIT(ffa_mem_list);
+static struct list_head ffa_frag_list = LIST_HEAD_INIT(ffa_frag_list);
+static spinlock_t ffa_mem_list_lock = SPIN_LOCK_UNLOCKED;
+
+static uint64_t next_handle = FFA_HANDLE_HYP_FLAG;
+
+static uint64_t reg_pair_to_64(uint32_t reg0, uint32_t reg1)
+{
+    return (uint64_t)reg0 << 32 | reg1;
+}
+
+static void reg_pair_from_64(uint32_t *reg0, uint32_t *reg1, uint64_t val)
+{
+    *reg0 = val >> 32;
+    *reg1 = val;
+}
+
+static bool ffa_get_version(uint32_t *vers)
+{
+    const struct arm_smccc_1_2_regs arg = {
+        .a0 = FFA_VERSION, .a1 = FFA_MY_VERSION,
+    };
+    struct arm_smccc_1_2_regs resp;
+
+    arm_smccc_1_2_smc(&arg, &resp);
+    if ( resp.a0 == FFA_RET_NOT_SUPPORTED )
+    {
+        printk(XENLOG_ERR "ffa: FFA_VERSION returned not supported\n");
+        return false;
+    }
+
+    *vers = resp.a0;
+    return true;
+}
+
+static uint32_t ffa_rxtx_map(register_t tx_addr, register_t rx_addr,
+                             uint32_t page_count)
+{
+    const struct arm_smccc_1_2_regs arg = {
+#ifdef CONFIG_ARM_64
+        .a0 = FFA_RXTX_MAP_64,
+#endif
+#ifdef CONFIG_ARM_32
+        .a0 = FFA_RXTX_MAP_32,
+#endif
+	.a1 = tx_addr, .a2 = rx_addr,
+        .a3 = page_count,
+    };
+    struct arm_smccc_1_2_regs resp;
+
+    arm_smccc_1_2_smc(&arg, &resp);
+
+    if ( resp.a0 == FFA_ERROR )
+    {
+        if ( resp.a2 )
+            return resp.a2;
+        else
+            return FFA_RET_NOT_SUPPORTED;
+    }
+
+    return FFA_RET_OK;
+}
+
+static uint32_t ffa_rxtx_unmap(uint16_t vm_id)
+{
+    const struct arm_smccc_1_2_regs arg = {
+        .a0 = FFA_RXTX_UNMAP, .a1 = vm_id,
+    };
+    struct arm_smccc_1_2_regs resp;
+
+    arm_smccc_1_2_smc(&arg, &resp);
+
+    if ( resp.a0 == FFA_ERROR )
+    {
+        if ( resp.a2 )
+            return resp.a2;
+        else
+            return FFA_RET_NOT_SUPPORTED;
+    }
+
+    return FFA_RET_OK;
+}
+
+static uint32_t ffa_partition_info_get(uint32_t w1, uint32_t w2, uint32_t w3,
+                                       uint32_t w4, uint32_t w5,
+                                       uint32_t *count)
+{
+    const struct arm_smccc_1_2_regs arg = {
+        .a0 = FFA_PARTITION_INFO_GET, .a1 = w1, .a2 = w2, .a3 = w3, .a4 = w4,
+        .a5 = w5,
+    };
+    struct arm_smccc_1_2_regs resp;
+
+    arm_smccc_1_2_smc(&arg, &resp);
+
+    if ( resp.a0 == FFA_ERROR )
+    {
+        if ( resp.a2 )
+            return resp.a2;
+        else
+            return FFA_RET_NOT_SUPPORTED;
+    }
+
+    *count = resp.a2;
+
+    return FFA_RET_OK;
+}
+
+static uint32_t ffa_rx_release(void)
+{
+    const struct arm_smccc_1_2_regs arg = { .a0 = FFA_RX_RELEASE, };
+    struct arm_smccc_1_2_regs resp;
+
+    arm_smccc_1_2_smc(&arg, &resp);
+
+    if ( resp.a0 == FFA_ERROR )
+    {
+        if ( resp.a2 )
+            return resp.a2;
+        else
+            return FFA_RET_NOT_SUPPORTED;
+    }
+
+    return FFA_RET_OK;
+}
+
+static int32_t ffa_mem_share(uint32_t tot_len, uint32_t frag_len,
+                             register_t addr, uint32_t pg_count,
+                             uint64_t *handle)
+{
+    struct arm_smccc_1_2_regs arg = {
+        .a0 = FFA_MEM_SHARE_32, .a1 = tot_len, .a2 = frag_len, .a3 = addr,
+        .a4 = pg_count,
+    };
+    struct arm_smccc_1_2_regs resp;
+
+    /*
+     * For arm64 we must use 64-bit calling convention if the buffer isn't
+     * passed in our tx buffer.
+     */
+    if (sizeof(addr) > 4 && addr)
+        arg.a0 = FFA_MEM_SHARE_64;
+
+    arm_smccc_1_2_smc(&arg, &resp);
+
+    switch ( resp.a0 ) {
+    case FFA_ERROR:
+        if ( resp.a2 )
+            return resp.a2;
+        else
+            return FFA_RET_NOT_SUPPORTED;
+    case FFA_SUCCESS_32:
+        *handle = reg_pair_to_64(resp.a3, resp.a2);
+        return FFA_RET_OK;
+    case FFA_MEM_FRAG_RX:
+        *handle = reg_pair_to_64(resp.a2, resp.a1);
+        return resp.a3;
+    default:
+            return FFA_RET_NOT_SUPPORTED;
+    }
+}
+
+static int32_t ffa_mem_frag_tx(uint64_t handle, uint32_t frag_len,
+                               uint16_t sender_id)
+{
+    struct arm_smccc_1_2_regs arg = {
+        .a0 = FFA_MEM_FRAG_TX, .a1 = handle & UINT32_MAX, .a2 = handle >> 32,
+        .a3 = frag_len, .a4 = (uint32_t)sender_id << 16,
+    };
+    struct arm_smccc_1_2_regs resp;
+
+    arm_smccc_1_2_smc(&arg, &resp);
+
+    switch ( resp.a0 ) {
+    case FFA_ERROR:
+        if ( resp.a2 )
+            return resp.a2;
+        else
+            return FFA_RET_NOT_SUPPORTED;
+    case FFA_SUCCESS_32:
+        return FFA_RET_OK;
+    case FFA_MEM_FRAG_RX:
+        return resp.a3;
+    default:
+            return FFA_RET_NOT_SUPPORTED;
+    }
+}
+
+static uint32_t ffa_mem_reclaim(uint32_t handle_lo, uint32_t handle_hi,
+                                uint32_t flags)
+{
+    const struct arm_smccc_1_2_regs arg = {
+        .a0 = FFA_MEM_RECLAIM, .a1 = handle_lo, .a2 = handle_hi, .a3 = flags,
+    };
+    struct arm_smccc_1_2_regs resp;
+
+    arm_smccc_1_2_smc(&arg, &resp);
+
+    if ( resp.a0 == FFA_ERROR )
+    {
+        if ( resp.a2 )
+            return resp.a2;
+        else
+            return FFA_RET_NOT_SUPPORTED;
+    }
+
+    return FFA_RET_OK;
+}
+
+static int32_t ffa_direct_req_send_vm(uint16_t sp_id, uint16_t vm_id,
+                                      uint8_t msg)
+{
+    uint32_t exp_resp = FFA_MSG_FLAG_FRAMEWORK;
+    int32_t res;
+
+    if ( msg != FFA_MSG_SEND_VM_CREATED && msg !=FFA_MSG_SEND_VM_DESTROYED )
+        return FFA_RET_INVALID_PARAMETERS;
+
+    if ( msg == FFA_MSG_SEND_VM_CREATED )
+        exp_resp |= FFA_MSG_RESP_VM_CREATED;
+    else
+        exp_resp |= FFA_MSG_RESP_VM_DESTROYED;
+
+    do {
+        const struct arm_smccc_1_2_regs arg = {
+            .a0 = FFA_MSG_SEND_DIRECT_REQ_32,
+            .a1 = sp_id,
+            .a2 = FFA_MSG_FLAG_FRAMEWORK | msg,
+            .a5 = vm_id,
+        };
+        struct arm_smccc_1_2_regs resp;
+
+        arm_smccc_1_2_smc(&arg, &resp);
+        if ( resp.a0 != FFA_MSG_SEND_DIRECT_RESP_32 || resp.a2 != exp_resp ) {
+            /*
+             * This is an invalid response, likely due to some error in the
+             * implementation of the ABI.
+             */
+            return FFA_RET_INVALID_PARAMETERS;
+        }
+        res = resp.a3;
+    } while ( res == FFA_RET_INTERRUPTED || res == FFA_RET_RETRY );
+
+    return res;
+}
+
+static u16 get_vm_id(struct domain *d)
+{
+    /* +1 since 0 is reserved for the hypervisor in FF-A */
+    return d->domain_id + 1;
+}
+
+static void set_regs(struct cpu_user_regs *regs, register_t v0, register_t v1,
+                     register_t v2, register_t v3, register_t v4, register_t v5,
+                     register_t v6, register_t v7)
+{
+        set_user_reg(regs, 0, v0);
+        set_user_reg(regs, 1, v1);
+        set_user_reg(regs, 2, v2);
+        set_user_reg(regs, 3, v3);
+        set_user_reg(regs, 4, v4);
+        set_user_reg(regs, 5, v5);
+        set_user_reg(regs, 6, v6);
+        set_user_reg(regs, 7, v7);
+}
+
+static void set_regs_error(struct cpu_user_regs *regs, uint32_t error_code)
+{
+    set_regs(regs, FFA_ERROR, 0, error_code, 0, 0, 0, 0, 0);
+}
+
+static void set_regs_success(struct cpu_user_regs *regs, uint32_t w2,
+                             uint32_t w3)
+{
+    set_regs(regs, FFA_SUCCESS_32, 0, w2, w3, 0, 0, 0, 0);
+}
+
+static void set_regs_frag_rx(struct cpu_user_regs *regs, uint32_t handle_lo,
+                             uint32_t handle_hi, uint32_t frag_offset,
+                             uint16_t sender_id)
+{
+    set_regs(regs, FFA_MEM_FRAG_RX, handle_lo, handle_hi, frag_offset,
+             (uint32_t)sender_id << 16, 0, 0, 0);
+}
+
+static void handle_version(struct cpu_user_regs *regs)
+{
+    struct domain *d = current->domain;
+    struct ffa_ctx *ctx = d->arch.ffa;
+    uint32_t vers = get_user_reg(regs, 1);
+
+    if ( vers < FFA_VERSION_1_1 )
+        vers = FFA_VERSION_1_0;
+    else
+        vers = FFA_VERSION_1_1;
+
+    ctx->guest_vers = vers;
+    set_regs(regs, vers, 0, 0, 0, 0, 0, 0, 0);
+}
+
+static uint32_t handle_rxtx_map(uint32_t fid, register_t tx_addr,
+                                register_t rx_addr, uint32_t page_count)
+{
+    uint32_t ret = FFA_RET_NOT_SUPPORTED;
+    struct domain *d = current->domain;
+    struct ffa_ctx *ctx = d->arch.ffa;
+    struct page_info *tx_pg;
+    struct page_info *rx_pg;
+    p2m_type_t t;
+    void *rx;
+    void *tx;
+
+    if ( !smccc_is_conv_64(fid) )
+    {
+        tx_addr &= UINT32_MAX;
+        rx_addr &= UINT32_MAX;
+    }
+
+    /* For now to keep things simple, only deal with a single page */
+    if ( page_count != 1 )
+        return FFA_RET_NOT_SUPPORTED;
+
+    /* Already mapped */
+    if ( ctx->rx )
+        return FFA_RET_DENIED;
+
+    tx_pg = get_page_from_gfn(d, gaddr_to_gfn(tx_addr), &t, P2M_ALLOC);
+    if ( !tx_pg )
+        return FFA_RET_NOT_SUPPORTED;
+    /* Only normal RAM for now */
+    if (t != p2m_ram_rw)
+        goto err_put_tx_pg;
+
+    rx_pg = get_page_from_gfn(d, gaddr_to_gfn(rx_addr), &t, P2M_ALLOC);
+    if ( !tx_pg )
+        goto err_put_tx_pg;
+    /* Only normal RAM for now */
+    if ( t != p2m_ram_rw )
+        goto err_put_rx_pg;
+
+    tx = __map_domain_page_global(tx_pg);
+    if ( !tx )
+        goto err_put_rx_pg;
+
+    rx = __map_domain_page_global(rx_pg);
+    if ( !rx )
+        goto err_unmap_tx;
+
+    ctx->rx = rx;
+    ctx->tx = tx;
+    ctx->rx_pg = rx_pg;
+    ctx->tx_pg = tx_pg;
+    ctx->page_count = 1;
+    ctx->tx_is_mine = true;
+    return FFA_RET_OK;
+
+err_unmap_tx:
+    unmap_domain_page_global(tx);
+err_put_rx_pg:
+    put_page(rx_pg);
+err_put_tx_pg:
+    put_page(tx_pg);
+    return ret;
+}
+
+static uint32_t handle_rxtx_unmap(void)
+{
+    struct domain *d = current->domain;
+    struct ffa_ctx *ctx = d->arch.ffa;
+    uint32_t ret;
+
+    if ( !ctx-> rx )
+        return FFA_RET_INVALID_PARAMETERS;
+
+    ret = ffa_rxtx_unmap(get_vm_id(d));
+    if ( ret )
+        return ret;
+
+    unmap_domain_page_global(ctx->rx);
+    unmap_domain_page_global(ctx->tx);
+    put_page(ctx->rx_pg);
+    put_page(ctx->tx_pg);
+    ctx->rx = NULL;
+    ctx->tx = NULL;
+    ctx->rx_pg = NULL;
+    ctx->tx_pg = NULL;
+    ctx->page_count = 0;
+    ctx->tx_is_mine = false;
+
+    return FFA_RET_OK;
+}
+
+static uint32_t handle_partition_info_get(uint32_t w1, uint32_t w2, uint32_t w3,
+                                          uint32_t w4, uint32_t w5,
+                                          uint32_t *count)
+{
+    uint32_t ret = FFA_RET_DENIED;
+    struct domain *d = current->domain;
+    struct ffa_ctx *ctx = d->arch.ffa;
+
+    if ( !ffa_page_count )
+        return FFA_RET_DENIED;
+
+    spin_lock(&ffa_buffer_lock);
+    if ( !ctx->page_count || !ctx->tx_is_mine )
+        goto out;
+    ret = ffa_partition_info_get(w1, w2, w3, w4, w5, count);
+    if ( ret )
+        goto out;
+    if ( ctx->guest_vers == FFA_VERSION_1_0 ) {
+        size_t n;
+        struct ffa_partition_info_1_1 *src = ffa_rx;
+        struct ffa_partition_info_1_0 *dst = ctx->rx;
+
+        for ( n = 0; n < *count; n++ ) {
+            dst[n].id = src[n].id;
+            dst[n].execution_context = src[n].execution_context;
+            dst[n].partition_properties = src[n].partition_properties;
+        }
+    } else {
+        size_t sz = *count * sizeof(struct ffa_partition_info_1_1);
+
+        memcpy(ctx->rx, ffa_rx, sz);
+    }
+    ffa_rx_release();
+    ctx->tx_is_mine = false;
+out:
+    spin_unlock(&ffa_buffer_lock);
+
+    return ret;
+}
+
+static uint32_t handle_rx_release(void)
+{
+    uint32_t ret = FFA_RET_DENIED;
+    struct domain *d = current->domain;
+    struct ffa_ctx *ctx = d->arch.ffa;
+
+    spin_lock(&ffa_buffer_lock);
+    if ( !ctx->page_count || ctx->tx_is_mine )
+        goto out;
+    ret = FFA_RET_OK;
+    ctx->tx_is_mine = true;
+out:
+    spin_unlock(&ffa_buffer_lock);
+
+    return ret;
+}
+
+static void handle_msg_send_direct_req(struct cpu_user_regs *regs, uint32_t fid)
+{
+    struct arm_smccc_1_2_regs arg = { .a0 = fid, };
+    struct arm_smccc_1_2_regs resp = { };
+    struct domain *d = current->domain;
+    struct ffa_ctx *ctx = d->arch.ffa;
+    uint32_t src_dst;
+    uint64_t mask;
+
+    if ( smccc_is_conv_64(fid) )
+        mask = 0xffffffffffffffff;
+    else
+        mask = 0xffffffff;
+
+    src_dst = get_user_reg(regs, 1);
+    if ( (src_dst >> 16) != get_vm_id(d) )
+    {
+        resp.a0 = FFA_ERROR;
+        resp.a2 = FFA_RET_INVALID_PARAMETERS;
+        goto out;
+    }
+
+    arg.a1 = src_dst;
+    arg.a2 = get_user_reg(regs, 2) & mask;
+    arg.a3 = get_user_reg(regs, 3) & mask;
+    arg.a4 = get_user_reg(regs, 4) & mask;
+    arg.a5 = get_user_reg(regs, 5) & mask;
+    arg.a6 = get_user_reg(regs, 6) & mask;
+    arg.a7 = get_user_reg(regs, 7) & mask;
+
+    while ( true ) {
+        arm_smccc_1_2_smc(&arg, &resp);
+
+        switch ( resp.a0 )
+        {
+        case FFA_INTERRUPT:
+            ctx->interrupted = true;
+            goto out;
+        case FFA_ERROR:
+        case FFA_SUCCESS_32:
+        case FFA_SUCCESS_64:
+        case FFA_MSG_SEND_DIRECT_RESP_32:
+        case FFA_MSG_SEND_DIRECT_RESP_64:
+            goto out;
+        default:
+            /* Bad fid, report back. */
+            memset(&arg, 0, sizeof(arg));
+            arg.a0 = FFA_ERROR;
+            arg.a1 = src_dst;
+            arg.a2 = FFA_RET_NOT_SUPPORTED;
+            continue;
+        }
+    }
+
+out:
+    set_user_reg(regs, 0, resp.a0);
+    set_user_reg(regs, 2, resp.a2 & mask);
+    set_user_reg(regs, 1, resp.a1 & mask);
+    set_user_reg(regs, 3, resp.a3 & mask);
+    set_user_reg(regs, 4, resp.a4 & mask);
+    set_user_reg(regs, 5, resp.a5 & mask);
+    set_user_reg(regs, 6, resp.a6 & mask);
+    set_user_reg(regs, 7, resp.a7 & mask);
+}
+
+static int get_shm_pages(struct domain *d, struct ffa_shm_mem *shm,
+                         struct ffa_address_range *range, uint32_t range_count,
+                         unsigned int start_page_idx,
+                         unsigned int *last_page_idx)
+{
+    unsigned int pg_idx = start_page_idx;
+    unsigned long gfn;
+    unsigned int n;
+    unsigned int m;
+    p2m_type_t t;
+    uint64_t addr;
+
+    for ( n = 0; n < range_count; n++ ) {
+        for ( m = 0; m < range[n].page_count; m++ ) {
+            if ( pg_idx >= shm->page_count )
+                return FFA_RET_INVALID_PARAMETERS;
+
+            addr = read_atomic(&range[n].address);
+            gfn = gaddr_to_gfn(addr + m * PAGE_SIZE);
+            shm->pages[pg_idx] = get_page_from_gfn(d, gfn, &t, P2M_ALLOC);
+            if ( !shm->pages[pg_idx] )
+                return FFA_RET_DENIED;
+            pg_idx++;
+            /* Only normal RAM for now */
+            if ( t != p2m_ram_rw )
+                return FFA_RET_DENIED;
+        }
+    }
+
+    *last_page_idx = pg_idx;
+
+    return FFA_RET_OK;
+}
+
+static void put_shm_pages(struct ffa_shm_mem *shm)
+{
+    unsigned int n;
+
+    for ( n = 0; n < shm->page_count && shm->pages[n]; n++ )
+    {
+        if ( shm->pages[n] ) {
+            put_page(shm->pages[n]);
+            shm->pages[n] = NULL;
+        }
+    }
+}
+
+static void init_range(struct ffa_address_range *addr_range,
+                       paddr_t pa)
+{
+    memset(addr_range, 0, sizeof(*addr_range));
+    addr_range->address = pa;
+    addr_range->page_count = 1;
+}
+
+static int share_shm(struct ffa_shm_mem *shm)
+{
+    uint32_t max_frag_len = ffa_page_count * PAGE_SIZE;
+    struct ffa_mem_transaction_1_1 *descr = ffa_tx;
+    struct ffa_mem_access *mem_access_array;
+    struct ffa_mem_region *region_descr;
+    struct ffa_address_range *addr_range;
+    paddr_t pa;
+    paddr_t last_pa;
+    unsigned int n;
+    uint32_t frag_len;
+    uint32_t tot_len;
+    int ret;
+    unsigned int range_count;
+    unsigned int range_base;
+    bool first;
+
+    memset(descr, 0, sizeof(*descr));
+    descr->sender_id = shm->sender_id;
+    descr->global_handle = shm->handle;
+    descr->mem_reg_attr = FFA_NORMAL_MEM_REG_ATTR;
+    descr->mem_access_count = 1;
+    descr->mem_access_size = sizeof(*mem_access_array);
+    descr->mem_access_offs = sizeof(*descr);
+    mem_access_array = (void *)(descr + 1);
+    region_descr = (void *)(mem_access_array + 1);
+
+    memset(mem_access_array, 0, sizeof(*mem_access_array));
+    mem_access_array[0].access_perm.endpoint_id = shm->ep_id;
+    mem_access_array[0].access_perm.perm = FFA_MEM_ACC_RW;
+    mem_access_array[0].region_offs = (vaddr_t)region_descr - (vaddr_t)ffa_tx;
+
+    memset(region_descr, 0, sizeof(*region_descr));
+    region_descr->total_page_count = shm->page_count;
+
+    region_descr->address_range_count = 1;
+    last_pa = page_to_maddr(shm->pages[0]);
+    for ( n = 1; n < shm->page_count; last_pa = pa, n++ )
+    {
+        pa = page_to_maddr(shm->pages[n]);
+        if ( last_pa + PAGE_SIZE == pa )
+        {
+            continue;
+        }
+        region_descr->address_range_count++;
+    }
+
+    tot_len = sizeof(*descr) + sizeof(*mem_access_array) +
+              sizeof(*region_descr) +
+              region_descr->address_range_count * sizeof(*addr_range);
+
+    addr_range = region_descr->address_range_array;
+    frag_len = (vaddr_t)(addr_range + 1) - (vaddr_t)ffa_tx;
+    last_pa = page_to_maddr(shm->pages[0]);
+    init_range(addr_range, last_pa);
+    first = true;
+    range_count = 1;
+    range_base = 0;
+    for ( n = 1; n < shm->page_count; last_pa = pa, n++ )
+    {
+        pa = page_to_maddr(shm->pages[n]);
+        if ( last_pa + PAGE_SIZE == pa )
+        {
+            addr_range->page_count++;
+            continue;
+        }
+
+        if (frag_len == max_frag_len) {
+            if (first)
+            {
+                ret = ffa_mem_share(tot_len, frag_len, 0, 0, &shm->handle);
+                first = false;
+            }
+            else
+            {
+                ret = ffa_mem_frag_tx(shm->handle, frag_len, shm->sender_id);
+            }
+            if (ret <= 0)
+                return ret;
+            range_base = range_count;
+            range_count = 0;
+            frag_len = sizeof(*addr_range);
+            addr_range = ffa_tx;
+        } else {
+            frag_len += sizeof(*addr_range);
+            addr_range++;
+        }
+        init_range(addr_range, pa);
+        range_count++;
+    }
+
+    if (first)
+        return ffa_mem_share(tot_len, frag_len, 0, 0, &shm->handle);
+    else
+        return ffa_mem_frag_tx(shm->handle, frag_len, shm->sender_id);
+}
+
+static int read_mem_transaction(uint32_t ffa_vers, void *buf, size_t blen,
+                                struct ffa_mem_transaction_x *trans)
+{
+    uint16_t mem_reg_attr;
+    uint32_t flags;
+    uint32_t count;
+    uint32_t offs;
+    uint32_t size;
+
+    if (ffa_vers >= FFA_VERSION_1_1) {
+        struct ffa_mem_transaction_1_1 *descr;
+
+        if (blen < sizeof(*descr))
+            return FFA_RET_INVALID_PARAMETERS;
+
+        descr = buf;
+        trans->sender_id = read_atomic(&descr->sender_id);
+        mem_reg_attr = read_atomic(&descr->mem_reg_attr);
+        flags = read_atomic(&descr->flags);
+        trans->global_handle = read_atomic(&descr->global_handle);
+        trans->tag = read_atomic(&descr->tag);
+
+        count = read_atomic(&descr->mem_access_count);
+        size = read_atomic(&descr->mem_access_size);
+        offs = read_atomic(&descr->mem_access_offs);
+    } else {
+        struct ffa_mem_transaction_1_0 *descr;
+
+        if (blen < sizeof(*descr))
+            return FFA_RET_INVALID_PARAMETERS;
+
+        descr = buf;
+        trans->sender_id = read_atomic(&descr->sender_id);
+        mem_reg_attr = read_atomic(&descr->mem_reg_attr);
+        flags = read_atomic(&descr->flags);
+        trans->global_handle = read_atomic(&descr->global_handle);
+        trans->tag = read_atomic(&descr->tag);
+
+        count = read_atomic(&descr->mem_access_count);
+        size = sizeof(struct ffa_mem_access);
+        offs = offsetof(struct ffa_mem_transaction_1_0, mem_access_array);
+    }
+
+    if (mem_reg_attr > UINT8_MAX || flags > UINT8_MAX || size > UINT8_MAX ||
+        count > UINT8_MAX || offs > UINT16_MAX)
+        return FFA_RET_INVALID_PARAMETERS;
+
+    /* Check that the endpoint memory access descriptor array fits */
+    if (size * count + offs > blen)
+        return FFA_RET_INVALID_PARAMETERS;
+
+    trans->mem_reg_attr = mem_reg_attr;
+    trans->flags = flags;
+    trans->mem_access_size = size;
+    trans->mem_access_count = count;
+    trans->mem_access_offs = offs;
+    return 0;
+}
+
+static int add_mem_share_frag(struct mem_frag_state *s, unsigned int offs,
+                              unsigned int frag_len)
+{
+    struct domain *d = current->domain;
+    unsigned int o = offs;
+    unsigned int l;
+    int ret;
+
+    if (frag_len < o)
+        return FFA_RET_INVALID_PARAMETERS;
+
+    /* Fill up the first struct ffa_address_range */
+    l = min_t(unsigned int, frag_len - o, sizeof(s->range) - s->range_offset);
+    memcpy((uint8_t *)&s->range + s->range_offset, s->buf + o, l);
+    s->range_offset += l;
+    o += l;
+    if (s->range_offset != sizeof(s->range))
+        goto out;
+    s->range_offset = 0;
+
+    while (true) {
+        ret = get_shm_pages(d, s->shm, &s->range, 1, s->current_page_idx,
+                            &s->current_page_idx);
+        if (ret)
+            return ret;
+        if (s->range_count == 1)
+            return 0;
+        s->range_count--;
+        if (frag_len - o < sizeof(s->range))
+            break;
+        memcpy(&s->range, s->buf + o, sizeof(s->range));
+        o += sizeof(s->range);
+    }
+
+    /* Collect any remaining bytes for the next struct ffa_address_range */
+    s->range_offset = frag_len - o;
+    memcpy(&s->range, s->buf + o, frag_len - o);
+out:
+    s->frag_offset += frag_len;
+    return s->frag_offset;
+}
+
+static void handle_mem_share(struct cpu_user_regs *regs)
+{
+    uint32_t tot_len = get_user_reg(regs, 1);
+    uint32_t frag_len = get_user_reg(regs, 2);
+    uint64_t addr = get_user_reg(regs, 3);
+    uint32_t page_count = get_user_reg(regs, 4);
+    struct ffa_mem_transaction_x trans;
+    struct ffa_mem_access *mem_access;
+    struct ffa_mem_region *region_descr;
+    struct domain *d = current->domain;
+    struct ffa_ctx *ctx = d->arch.ffa;
+    struct ffa_shm_mem *shm = NULL;
+    unsigned int last_page_idx = 0;
+    uint32_t range_count;
+    uint32_t region_offs;
+    int ret = FFA_RET_DENIED;
+    uint32_t handle_hi = 0;
+    uint32_t handle_lo = 0;
+
+    /*
+     * We're only accepting memory transaction descriptors via the rx/tx
+     * buffer.
+     */
+    if ( addr ) {
+        ret = FFA_RET_NOT_SUPPORTED;
+        goto out_unlock;
+    }
+
+    /* Check that fragment legnth doesn't exceed total length */
+    if (frag_len > tot_len) {
+        ret = FFA_RET_INVALID_PARAMETERS;
+        goto out_unlock;
+    }
+
+    spin_lock(&ffa_buffer_lock);
+
+    if ( frag_len > ctx->page_count * PAGE_SIZE )
+        goto out_unlock;
+
+    if ( !ffa_page_count ) {
+        ret = FFA_RET_NO_MEMORY;
+        goto out_unlock;
+    }
+
+    ret = read_mem_transaction(ctx->guest_vers, ctx->tx, frag_len, &trans);
+    if (ret)
+        goto out_unlock;
+
+    if ( trans.mem_reg_attr != FFA_NORMAL_MEM_REG_ATTR )
+    {
+        ret = FFA_RET_NOT_SUPPORTED;
+        goto out;
+    }
+
+    /* Only supports sharing it with one SP for now */
+    if ( trans.mem_access_count != 1 )
+    {
+        ret = FFA_RET_NOT_SUPPORTED;
+        goto out_unlock;
+    }
+
+    if ( trans.sender_id != get_vm_id(d) )
+    {
+        ret = FFA_RET_INVALID_PARAMETERS;
+        goto out_unlock;
+    }
+
+    /* Check that it fits in the supplied data */
+    if ( trans.mem_access_offs + trans.mem_access_size > frag_len)
+        goto out_unlock;
+
+    mem_access = (void *)((vaddr_t)ctx->tx + trans.mem_access_offs);
+    if ( read_atomic(&mem_access->access_perm.perm) != FFA_MEM_ACC_RW )
+    {
+        ret = FFA_RET_NOT_SUPPORTED;
+        goto out_unlock;
+    }
+
+    region_offs = read_atomic(&mem_access->region_offs);
+    if (sizeof(*region_descr) + region_offs > frag_len) {
+        ret = FFA_RET_NOT_SUPPORTED;
+        goto out_unlock;
+    }
+
+    region_descr = (void *)((vaddr_t)ctx->tx + region_offs);
+    range_count = read_atomic(&region_descr->address_range_count);
+    page_count = read_atomic(&region_descr->total_page_count);
+
+    shm = xzalloc_flex_struct(struct ffa_shm_mem, pages, page_count);
+    if ( !shm )
+    {
+        ret = FFA_RET_NO_MEMORY;
+        goto out;
+    }
+    shm->sender_id = trans.sender_id;
+    shm->ep_id = read_atomic(&mem_access->access_perm.endpoint_id);
+    shm->page_count = page_count;
+
+    if (frag_len != tot_len) {
+        struct mem_frag_state *s = xzalloc(struct mem_frag_state);
+
+        if (!s) {
+            ret = FFA_RET_NO_MEMORY;
+            goto out;
+        }
+        s->shm = shm;
+        s->range_count = range_count;
+        s->buf = ctx->tx;
+        s->buf_size = ffa_page_count * PAGE_SIZE;
+        ret = add_mem_share_frag(s, sizeof(*region_descr)  + region_offs,
+                                 frag_len);
+        if (ret <= 0) {
+            xfree(s);
+            if (ret < 0)
+                goto out;
+        } else {
+            shm->handle = next_handle++;
+            reg_pair_from_64(&handle_hi, &handle_lo, shm->handle);
+            spin_lock(&ffa_mem_list_lock);
+            list_add_tail(&s->list, &ffa_frag_list);
+            spin_unlock(&ffa_mem_list_lock);
+        }
+        goto out_unlock;
+    }
+
+    /*
+     * Check that the Composite memory region descriptor fits.
+     */
+    if ( sizeof(*region_descr) + region_offs +
+         range_count * sizeof(struct ffa_address_range) > frag_len) {
+        ret = FFA_RET_INVALID_PARAMETERS;
+        goto out;
+    }
+
+    ret = get_shm_pages(d, shm, region_descr->address_range_array, range_count,
+                        0, &last_page_idx);
+    if ( ret )
+        goto out;
+    if (last_page_idx != shm->page_count) {
+        ret = FFA_RET_INVALID_PARAMETERS;
+        goto out;
+    }
+
+    /* Note that share_shm() uses our tx buffer */
+    ret = share_shm(shm);
+    if ( ret )
+        goto out;
+
+    spin_lock(&ffa_mem_list_lock);
+    list_add_tail(&shm->list, &ffa_mem_list);
+    spin_unlock(&ffa_mem_list_lock);
+
+    reg_pair_from_64(&handle_hi, &handle_lo, shm->handle);
+
+out:
+    if ( ret && shm )
+    {
+        put_shm_pages(shm);
+        xfree(shm);
+    }
+out_unlock:
+    spin_unlock(&ffa_buffer_lock);
+
+    if ( ret > 0 )
+            set_regs_frag_rx(regs, handle_lo, handle_hi, ret, trans.sender_id);
+    else if ( ret == 0)
+            set_regs_success(regs, handle_lo, handle_hi);
+    else
+            set_regs_error(regs, ret);
+}
+
+static struct mem_frag_state *find_frag_state(uint64_t handle)
+{
+    struct mem_frag_state *s;
+
+    list_for_each_entry(s, &ffa_frag_list, list)
+        if ( s->shm->handle == handle)
+            return s;
+
+    return NULL;
+}
+
+static void handle_mem_frag_tx(struct cpu_user_regs *regs)
+{
+    uint32_t frag_len = get_user_reg(regs, 3);
+    uint32_t handle_lo = get_user_reg(regs, 1);
+    uint32_t handle_hi = get_user_reg(regs, 2);
+    uint64_t handle = reg_pair_to_64(handle_hi, handle_lo);
+    struct mem_frag_state *s;
+    uint16_t sender_id = 0;
+    int ret;
+
+    spin_lock(&ffa_buffer_lock);
+    s = find_frag_state(handle);
+    if (!s) {
+        ret = FFA_RET_INVALID_PARAMETERS;
+        goto out;
+    }
+    sender_id = s->shm->sender_id;
+
+    if (frag_len > s->buf_size) {
+        ret = FFA_RET_INVALID_PARAMETERS;
+        goto out;
+    }
+
+    ret = add_mem_share_frag(s, 0, frag_len);
+    if (ret == 0) {
+        /* Note that share_shm() uses our tx buffer */
+        ret = share_shm(s->shm);
+        if (ret == 0) {
+            spin_lock(&ffa_mem_list_lock);
+            list_add_tail(&s->shm->list, &ffa_mem_list);
+            spin_unlock(&ffa_mem_list_lock);
+        } else {
+            put_shm_pages(s->shm);
+            xfree(s->shm);
+        }
+        spin_lock(&ffa_mem_list_lock);
+        list_del(&s->list);
+        spin_unlock(&ffa_mem_list_lock);
+        xfree(s);
+    } else if (ret < 0) {
+        put_shm_pages(s->shm);
+        xfree(s->shm);
+        spin_lock(&ffa_mem_list_lock);
+        list_del(&s->list);
+        spin_unlock(&ffa_mem_list_lock);
+        xfree(s);
+    }
+out:
+    spin_unlock(&ffa_buffer_lock);
+
+    if ( ret > 0 )
+            set_regs_frag_rx(regs, handle_lo, handle_hi, ret, sender_id);
+    else if ( ret == 0)
+            set_regs_success(regs, handle_lo, handle_hi);
+    else
+            set_regs_error(regs, ret);
+}
+
+static int handle_mem_reclaim(uint64_t handle, uint32_t flags)
+{
+    struct ffa_shm_mem *shm;
+    uint32_t handle_hi;
+    uint32_t handle_lo;
+    int ret;
+
+    spin_lock(&ffa_mem_list_lock);
+    list_for_each_entry(shm, &ffa_mem_list, list) {
+        if ( shm->handle == handle )
+            goto found_it;
+    }
+    shm = NULL;
+found_it:
+    spin_unlock(&ffa_mem_list_lock);
+
+    if ( !shm )
+        return FFA_RET_INVALID_PARAMETERS;
+
+    reg_pair_from_64(&handle_hi, &handle_lo, handle);
+    ret = ffa_mem_reclaim(handle_lo, handle_hi, flags);
+    if ( ret )
+        return ret;
+
+    spin_lock(&ffa_mem_list_lock);
+    list_del(&shm->list);
+    spin_unlock(&ffa_mem_list_lock);
+
+    put_shm_pages(shm);
+    xfree(shm);
+
+    return ret;
+}
+
+bool ffa_handle_call(struct cpu_user_regs *regs, uint32_t fid)
+{
+    struct domain *d = current->domain;
+    struct ffa_ctx *ctx = d->arch.ffa;
+    uint32_t count;
+    uint32_t e;
+
+    if ( !ctx )
+        return false;
+
+    switch ( fid )
+    {
+    case FFA_VERSION:
+        handle_version(regs);
+        return true;
+    case FFA_ID_GET:
+        set_regs_success(regs, get_vm_id(d), 0);
+        return true;
+    case FFA_RXTX_MAP_32:
+#ifdef CONFIG_ARM_64
+    case FFA_RXTX_MAP_64:
+#endif
+        e = handle_rxtx_map(fid, get_user_reg(regs, 1), get_user_reg(regs, 2),
+                            get_user_reg(regs, 3));
+        if ( e )
+            set_regs_error(regs, e);
+        else
+            set_regs_success(regs, 0, 0);
+        return true;
+    case FFA_RXTX_UNMAP:
+        e = handle_rxtx_unmap();
+        if ( e )
+            set_regs_error(regs, e);
+        else
+            set_regs_success(regs, 0, 0);
+        return true;
+    case FFA_PARTITION_INFO_GET:
+        e = handle_partition_info_get(get_user_reg(regs, 1),
+                                      get_user_reg(regs, 2),
+                                      get_user_reg(regs, 3),
+                                      get_user_reg(regs, 4),
+                                      get_user_reg(regs, 5), &count);
+        if ( e )
+            set_regs_error(regs, e);
+        else
+            set_regs_success(regs, count, 0);
+        return true;
+    case FFA_RX_RELEASE:
+        e = handle_rx_release();
+        if ( e )
+            set_regs_error(regs, e);
+        else
+            set_regs_success(regs, 0, 0);
+        return true;
+    case FFA_MSG_SEND_DIRECT_REQ_32:
+#ifdef CONFIG_ARM_64
+    case FFA_MSG_SEND_DIRECT_REQ_64:
+#endif
+        handle_msg_send_direct_req(regs, fid);
+        return true;
+    case FFA_MEM_SHARE_32:
+#ifdef CONFIG_ARM_64
+    case FFA_MEM_SHARE_64:
+#endif
+        handle_mem_share(regs);
+        return true;
+    case FFA_MEM_RECLAIM:
+        e = handle_mem_reclaim(reg_pair_to_64(get_user_reg(regs, 2),
+                                              get_user_reg(regs, 1)),
+                               get_user_reg(regs, 3));
+        if ( e )
+            set_regs_error(regs, e);
+        else
+            set_regs_success(regs, 0, 0);
+        return true;
+    case FFA_MEM_FRAG_TX:
+        handle_mem_frag_tx(regs);
+        return true;
+
+    default:
+        printk(XENLOG_ERR "ffa: unhandled fid 0x%x\n", fid);
+        return false;
+    }
+}
+
+int ffa_domain_init(struct domain *d)
+{
+    struct ffa_ctx *ctx;
+    unsigned int n;
+    unsigned int m;
+    unsigned int c_pos;
+    int32_t res;
+
+    if ( !ffa_version )
+        return 0;
+
+    ctx = xzalloc(struct ffa_ctx);
+    if ( !ctx )
+        return -ENOMEM;
+
+    for ( n = 0; n < subsr_vm_created_count; n++ ) {
+        res = ffa_direct_req_send_vm(subsr_vm_created[n], get_vm_id(d),
+                                     FFA_MSG_SEND_VM_CREATED);
+        if ( res ) {
+            printk(XENLOG_ERR "ffa: Failed to report creation of vm_id %u to  %u: res %d\n",
+                   get_vm_id(d), subsr_vm_created[n], res);
+            c_pos = n;
+            goto err;
+        }
+    }
+
+    d->arch.ffa = ctx;
+
+    return 0;
+
+err:
+    /* Undo any already sent vm created messaged */
+    for ( n = 0; n < c_pos; n++ )
+        for ( m = 0; m < subsr_vm_destroyed_count; m++ )
+            if ( subsr_vm_destroyed[m] == subsr_vm_created[n] )
+                ffa_direct_req_send_vm(subsr_vm_destroyed[n], get_vm_id(d),
+                                       FFA_MSG_SEND_VM_DESTROYED);
+    return -ENOMEM;
+}
+
+int ffa_relinquish_resources(struct domain *d)
+{
+    struct ffa_ctx *ctx = d->arch.ffa;
+    unsigned int n;
+    int32_t res;
+
+    if ( !ctx )
+        return 0;
+
+    for ( n = 0; n < subsr_vm_destroyed_count; n++ ) {
+        res = ffa_direct_req_send_vm(subsr_vm_destroyed[n], get_vm_id(d),
+                                     FFA_MSG_SEND_VM_DESTROYED);
+
+        if ( res )
+            printk(XENLOG_ERR "ffa: Failed to report destruction of vm_id %u to  %u: res %d\n",
+                   get_vm_id(d), subsr_vm_destroyed[n], res);
+    }
+
+    XFREE(d->arch.ffa);
+
+    return 0;
+}
+
+static bool __init init_subscribers(void)
+{
+    struct ffa_partition_info_1_1 *fpi;
+    bool ret = false;
+    uint32_t count;
+    uint32_t e;
+    uint32_t n;
+    uint32_t c_pos;
+    uint32_t d_pos;
+
+    if ( ffa_version < FFA_VERSION_1_1 )
+        return true;
+
+    e = ffa_partition_info_get(0, 0, 0, 0, 1, &count);
+    ffa_rx_release();
+    if ( e ) {
+        printk(XENLOG_ERR "ffa: Failed to get list of SPs: %d\n", (int)e);
+        goto out;
+    }
+
+    fpi = ffa_rx;
+    subsr_vm_created_count = 0;
+    subsr_vm_destroyed_count = 0;
+    for ( n = 0; n < count; n++ ) {
+        if (fpi[n].partition_properties & FFA_PART_PROP_NOTIF_CREATED)
+            subsr_vm_created_count++;
+        if (fpi[n].partition_properties & FFA_PART_PROP_NOTIF_DESTROYED)
+            subsr_vm_destroyed_count++;
+    }
+
+    if ( subsr_vm_created_count )
+        subsr_vm_created = xzalloc_array(uint16_t, subsr_vm_created_count);
+    if ( subsr_vm_destroyed_count )
+        subsr_vm_destroyed = xzalloc_array(uint16_t, subsr_vm_destroyed_count);
+    if ( (subsr_vm_created_count && !subsr_vm_created) ||
+        (subsr_vm_destroyed_count && !subsr_vm_destroyed) ) {
+        printk(XENLOG_ERR "ffa: Failed to allocate subscription lists\n");
+        subsr_vm_created_count = 0;
+        subsr_vm_destroyed_count = 0;
+        XFREE(subsr_vm_created);
+        XFREE(subsr_vm_destroyed);
+        goto out;
+    }
+
+    for ( c_pos = 0, d_pos = 0, n = 0; n < count; n++ ) {
+        if (fpi[n].partition_properties & FFA_PART_PROP_NOTIF_CREATED)
+            subsr_vm_created[c_pos++] = fpi[n].id;
+        if (fpi[n].partition_properties & FFA_PART_PROP_NOTIF_DESTROYED)
+            subsr_vm_destroyed[d_pos++] = fpi[n].id;
+    }
+
+    ret = true;
+out:
+    ffa_rx_release();
+    return ret;
+}
+
+static int __init ffa_init(void)
+{
+    uint32_t vers;
+    uint32_t e;
+    unsigned int major_vers;
+    unsigned int minor_vers;
+
+    /*
+     * psci_init_smccc() updates this value with what's reported by EL-3
+     * or secure world.
+     */
+    if ( smccc_ver < ARM_SMCCC_VERSION_1_2 )
+    {
+        printk(XENLOG_ERR
+               "ffa: unsupported SMCCC version %#x (need at least %#x)\n",
+               smccc_ver, ARM_SMCCC_VERSION_1_2);
+        return 0;
+    }
+
+    if ( !ffa_get_version(&vers) )
+        return 0;
+
+    if ( vers < FFA_MIN_VERSION || vers > FFA_MY_VERSION )
+    {
+        printk(XENLOG_ERR "ffa: Incompatible version %#x found\n", vers);
+        return 0;
+    }
+
+    major_vers = (vers >> FFA_VERSION_MAJOR_SHIFT) & FFA_VERSION_MAJOR_MASK;
+    minor_vers = vers & FFA_VERSION_MINOR_MASK;
+    printk(XENLOG_ERR "ARM FF-A Mediator version %u.%u\n",
+           FFA_VERSION_MAJOR, FFA_VERSION_MINOR);
+    printk(XENLOG_ERR "ARM FF-A Firmware version %u.%u\n",
+           major_vers, minor_vers);
+
+    ffa_rx = alloc_xenheap_pages(0, 0);
+    if ( !ffa_rx )
+        return 0;
+
+    ffa_tx = alloc_xenheap_pages(0, 0);
+    if ( !ffa_tx )
+        goto err_free_ffa_rx;
+
+    e = ffa_rxtx_map(__pa(ffa_tx), __pa(ffa_rx), 1);
+    if ( e )
+    {
+        printk(XENLOG_ERR "ffa: Failed to map rxtx: error %d\n", (int)e);
+        goto err_free_ffa_tx;
+    }
+    ffa_page_count = 1;
+    ffa_version = vers;
+
+    if ( !init_subscribers() )
+        goto err_free_ffa_tx;
+
+    return 0;
+
+err_free_ffa_tx:
+    free_xenheap_pages(ffa_tx, 0);
+    ffa_tx = NULL;
+err_free_ffa_rx:
+    free_xenheap_pages(ffa_rx, 0);
+    ffa_rx = NULL;
+    ffa_page_count = 0;
+    ffa_version = 0;
+    XFREE(subsr_vm_created);
+    subsr_vm_created_count = 0;
+    XFREE(subsr_vm_destroyed);
+    subsr_vm_destroyed_count = 0;
+    return 0;
+}
+
+__initcall(ffa_init);
diff --git a/xen/arch/arm/include/asm/domain.h b/xen/arch/arm/include/asm/domain.h
index ed63c2b6f91f..b3dee269bced 100644
--- a/xen/arch/arm/include/asm/domain.h
+++ b/xen/arch/arm/include/asm/domain.h
@@ -103,6 +103,10 @@ struct arch_domain
     void *tee;
 #endif
 
+#ifdef CONFIG_FFA
+    void *ffa;
+#endif
+
     bool directmap;
 }  __cacheline_aligned;
 
diff --git a/xen/arch/arm/include/asm/ffa.h b/xen/arch/arm/include/asm/ffa.h
new file mode 100644
index 000000000000..1c6ce6421294
--- /dev/null
+++ b/xen/arch/arm/include/asm/ffa.h
@@ -0,0 +1,71 @@
+/*
+ * xen/arch/arm/ffa.c
+ *
+ * Arm Firmware Framework for ARMv8-A(FFA) mediator
+ *
+ * Copyright (C) 2021  Linaro Limited
+ *
+ * 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.
+ */
+
+#ifndef __ASM_ARM_FFA_H__
+#define __ASM_ARM_FFA_H__
+
+#include <xen/const.h>
+
+#include <asm/smccc.h>
+#include <asm/types.h>
+
+#define FFA_FNUM_MIN_VALUE              _AC(0x60,U)
+#define FFA_FNUM_MAX_VALUE              _AC(0x86,U)
+
+static inline bool is_ffa_fid(uint32_t fid)
+{
+    uint32_t fn = fid & ARM_SMCCC_FUNC_MASK;
+
+    return fn >= FFA_FNUM_MIN_VALUE && fn <= FFA_FNUM_MAX_VALUE;
+}
+
+#ifdef CONFIG_FFA
+#define FFA_NR_FUNCS    11
+
+bool ffa_handle_call(struct cpu_user_regs *regs, uint32_t fid);
+int ffa_domain_init(struct domain *d);
+int ffa_relinquish_resources(struct domain *d);
+#else
+#define FFA_NR_FUNCS    0
+
+static inline bool ffa_handle_call(struct cpu_user_regs *regs, uint32_t fid)
+{
+    return false;
+}
+
+static inline int ffa_domain_init(struct domain *d)
+{
+    return 0;
+}
+
+static inline int ffa_relinquish_resources(struct domain *d)
+{
+    return 0;
+}
+#endif
+
+#endif /*__ASM_ARM_FFA_H__*/
diff --git a/xen/arch/arm/vsmc.c b/xen/arch/arm/vsmc.c
index 6f90c08a6304..34586025eff8 100644
--- a/xen/arch/arm/vsmc.c
+++ b/xen/arch/arm/vsmc.c
@@ -20,6 +20,7 @@
 #include <public/arch-arm/smccc.h>
 #include <asm/cpuerrata.h>
 #include <asm/cpufeature.h>
+#include <asm/ffa.h>
 #include <asm/monitor.h>
 #include <asm/regs.h>
 #include <asm/smccc.h>
@@ -32,7 +33,7 @@
 #define XEN_SMCCC_FUNCTION_COUNT 3
 
 /* Number of functions currently supported by Standard Service Service Calls. */
-#define SSSC_SMCCC_FUNCTION_COUNT (3 + VPSCI_NR_FUNCS)
+#define SSSC_SMCCC_FUNCTION_COUNT (3 + VPSCI_NR_FUNCS + FFA_NR_FUNCS)
 
 static bool fill_uid(struct cpu_user_regs *regs, xen_uuid_t uuid)
 {
@@ -196,13 +197,23 @@ static bool handle_existing_apis(struct cpu_user_regs *regs)
     return do_vpsci_0_1_call(regs, fid);
 }
 
+static bool is_psci_fid(uint32_t fid)
+{
+    uint32_t fn = fid & ARM_SMCCC_FUNC_MASK;
+
+    return fn >= 0 && fn <= 0x1fU;
+}
+
 /* PSCI 0.2 interface and other Standard Secure Calls */
 static bool handle_sssc(struct cpu_user_regs *regs)
 {
     uint32_t fid = (uint32_t)get_user_reg(regs, 0);
 
-    if ( do_vpsci_0_2_call(regs, fid) )
-        return true;
+    if ( is_psci_fid(fid) )
+        return do_vpsci_0_2_call(regs, fid);
+
+    if ( is_ffa_fid(fid) )
+        return ffa_handle_call(regs, fid);
 
     switch ( fid )
     {
