[PATCH v3 10/10] xen/arm: ffa: Add indirect message support

[Bertrand Marquis <bertrand.marquis@xxxxxxx>]

Add support for FFA_MSG_SEND2 to send indirect messages from a VM to a
secure partition.

Signed-off-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
Changes in v3:
- in ffa_handle_msg_send2 use ffa_get_vm_id instead of a local variable
  to make sure that we use the right VM ID as source without having a
  potential solution for the VM to give a wrong identity.
Changes in v2:
- rebase
---
 xen/arch/arm/tee/ffa.c         |  5 ++++
 xen/arch/arm/tee/ffa_msg.c     | 50 ++++++++++++++++++++++++++++++++++
 xen/arch/arm/tee/ffa_private.h |  1 +
 3 files changed, 56 insertions(+)

diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
index 04d2403415fe..87775ed88ffd 100644
--- a/xen/arch/arm/tee/ffa.c
+++ b/xen/arch/arm/tee/ffa.c
@@ -101,6 +101,7 @@ static const struct ffa_fw_abi ffa_fw_abi_needed[] = {
     FW_ABI(FFA_MEM_RECLAIM),
     FW_ABI(FFA_MSG_SEND_DIRECT_REQ_32),
     FW_ABI(FFA_MSG_SEND_DIRECT_REQ_64),
+    FW_ABI(FFA_MSG_SEND2),
 };
 
 /*
@@ -195,6 +196,7 @@ static void handle_features(struct cpu_user_regs *regs)
     case FFA_PARTITION_INFO_GET:
     case FFA_MSG_SEND_DIRECT_REQ_32:
     case FFA_MSG_SEND_DIRECT_REQ_64:
+    case FFA_MSG_SEND2:
         ffa_set_regs_success(regs, 0, 0);
         break;
     case FFA_MEM_SHARE_64:
@@ -275,6 +277,9 @@ static bool ffa_handle_call(struct cpu_user_regs *regs)
     case FFA_MSG_SEND_DIRECT_REQ_64:
         ffa_handle_msg_send_direct_req(regs, fid);
         return true;
+    case FFA_MSG_SEND2:
+        e = ffa_handle_msg_send2(regs);
+        break;
     case FFA_MEM_SHARE_32:
     case FFA_MEM_SHARE_64:
         ffa_handle_mem_share(regs);
diff --git a/xen/arch/arm/tee/ffa_msg.c b/xen/arch/arm/tee/ffa_msg.c
index ae263e54890e..ee594e737fc7 100644
--- a/xen/arch/arm/tee/ffa_msg.c
+++ b/xen/arch/arm/tee/ffa_msg.c
@@ -12,6 +12,15 @@
 
 #include "ffa_private.h"
 
+/* Encoding of partition message in RX/TX buffer */
+struct ffa_part_msg_rxtx {
+    uint32_t flags;
+    uint32_t reserved;
+    uint32_t msg_offset;
+    uint32_t send_recv_id;
+    uint32_t msg_size;
+};
+
 void ffa_handle_msg_send_direct_req(struct cpu_user_regs *regs, uint32_t fid)
 {
     struct arm_smccc_1_2_regs arg = { .a0 = fid, };
@@ -78,3 +87,44 @@ out:
                  resp.a4 & mask, resp.a5 & mask, resp.a6 & mask,
                  resp.a7 & mask);
 }
+
+int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs)
+{
+    struct domain *src_d = current->domain;
+    struct ffa_ctx *src_ctx = src_d->arch.tee;
+    const struct ffa_part_msg_rxtx *src_msg;
+    uint16_t dst_id, src_id;
+    int32_t ret;
+
+    if ( !ffa_fw_supports_fid(FFA_MSG_SEND2) )
+        return FFA_RET_NOT_SUPPORTED;
+
+    if ( !spin_trylock(&src_ctx->tx_lock) )
+        return FFA_RET_BUSY;
+
+    src_msg = src_ctx->tx;
+    src_id = src_msg->send_recv_id >> 16;
+    dst_id = src_msg->send_recv_id & GENMASK(15,0);
+
+    if ( src_id != ffa_get_vm_id(src_d) || !FFA_ID_IS_SECURE(dst_id) )
+    {
+        ret = FFA_RET_INVALID_PARAMETERS;
+        goto out_unlock_tx;
+    }
+
+    /* check source message fits in buffer */
+    if ( src_ctx->page_count * FFA_PAGE_SIZE <
+         src_msg->msg_offset + src_msg->msg_size ||
+         src_msg->msg_offset < sizeof(struct ffa_part_msg_rxtx) )
+    {
+        ret = FFA_RET_INVALID_PARAMETERS;
+        goto out_unlock_tx;
+    }
+
+    ret = ffa_simple_call(FFA_MSG_SEND2,
+                          ((uint32_t)ffa_get_vm_id(src_d)) << 16, 0, 0, 0);
+
+out_unlock_tx:
+    spin_unlock(&src_ctx->tx_lock);
+    return ret;
+}
diff --git a/xen/arch/arm/tee/ffa_private.h b/xen/arch/arm/tee/ffa_private.h
index 973ee55be09b..d441c0ca5598 100644
--- a/xen/arch/arm/tee/ffa_private.h
+++ b/xen/arch/arm/tee/ffa_private.h
@@ -359,6 +359,7 @@ void ffa_handle_notification_get(struct cpu_user_regs 
*regs);
 int ffa_handle_notification_set(struct cpu_user_regs *regs);
 
 void ffa_handle_msg_send_direct_req(struct cpu_user_regs *regs, uint32_t fid);
+int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs);
 
 static inline uint16_t ffa_get_vm_id(const struct domain *d)
 {
-- 
2.47.0