[xen master] xen/arm: ffa: add defines for sharing memory

[patchbot@xxxxxxx]

commit 8a36b557a5cb13cdfa24374278a4e8a67f48a5bf
Author:     Jens Wiklander <jens.wiklander@xxxxxxxxxx>
AuthorDate: Mon Jul 31 14:15:29 2023 +0200
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Fri Aug 18 09:29:23 2023 +0100

    xen/arm: ffa: add defines for sharing memory
    
    According to DEN0077A version 1.1 REL0
    - Section 10.9.2 Memory region handle, page 167
    - Table 10.18 at page 175
    - Table 10.15 at page 168
    - Section 10.11.4 Flags usage, page 184-187
    add defines needed for sharing using the function FFA_MEM_SHARE and
    friends.
    
    Also add limits for how many shared buffers that a guest can have at
    once and how large a shared buffer can be at most.
    
    Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
    Reviewed-by: Henry Wang <Henry.Wang@xxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
 xen/arch/arm/tee/ffa.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
index d8305f6d21..2a7b512189 100644
--- a/xen/arch/arm/tee/ffa.c
+++ b/xen/arch/arm/tee/ffa.c
@@ -5,6 +5,14 @@
  * Arm Firmware Framework for ARMv8-A (FF-A) mediator
  *
  * Copyright (C) 2023  Linaro Limited
+ *
+ * References:
+ * FF-A-1.0-REL: FF-A specification version 1.0 available at
+ *               https://developer.arm.com/documentation/den0077/a
+ * FF-A-1.1-REL0: FF-A specification version 1.1 available at
+ *                https://developer.arm.com/documentation/den0077/e
+ * TEEC-1.0C: TEE Client API Specification version 1.0c available at
+ *            
https://globalplatform.org/specs-library/tee-client-api-specification/
  */
 
 #include <xen/bitops.h>
@@ -80,6 +88,56 @@
  */
 #define FFA_MAX_RXTX_PAGE_COUNT         1
 
+/*
+ * Limit for shared buffer size. Please note that this define limits
+ * number of pages.
+ *
+ * FF-A doesn't have any direct requirements on GlobalPlatform or vice
+ * versa, but an implementation can very well use FF-A in order to provide
+ * a GlobalPlatform interface on top.
+ *
+ * Global Platform specification for TEE requires that any TEE
+ * implementation should allow to share buffers with size of at least
+ * 512KB, defined in TEEC-1.0C page 24, Table 4-1,
+ * TEEC_CONFIG_SHAREDMEM_MAX_SIZE.
+ * Due to overhead which can be hard to predict exactly, double this number
+ * to give a safe margin.
+ */
+#define FFA_MAX_SHM_PAGE_COUNT          (2 * SZ_512K / FFA_PAGE_SIZE)
+
+/*
+ * Limits the number of shared buffers that guest can have at once. This
+ * is to prevent case, when guests trick XEN into exhausting its own
+ * memory by allocating many small buffers. This value has been chosen
+ * arbitrarily.
+ */
+#define FFA_MAX_SHM_COUNT               32
+
+/* FF-A-1.1-REL0 section 10.9.2 Memory region handle, page 167 */
+#define FFA_HANDLE_HYP_FLAG             BIT(63, ULL)
+#define FFA_HANDLE_INVALID              0xffffffffffffffffULL
+
+/*
+ * Memory attributes: Normal memory, Write-Back cacheable, Inner shareable
+ * Defined in FF-A-1.1-REL0 Table 10.18 at page 175.
+ */
+#define FFA_NORMAL_MEM_REG_ATTR         0x2fU
+/*
+ * Memory access permissions: Read-write
+ * Defined in FF-A-1.1-REL0 Table 10.15 at page 168.
+ */
+#define FFA_MEM_ACC_RW                  0x2U
+
+/* FF-A-1.1-REL0 section 10.11.4 Flags usage, page 184-187 */
+/* 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 (1U << 3)
+
 /*
  * Flags and field values used for the MSG_SEND_DIRECT_REQ/RESP:
  * BIT(31): Framework or partition message
--
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