[xen master] optee: enable OPTEE_SMC_SEC_CAP_MEMREF_NULL capability

[patchbot@xxxxxxx]

commit d4fb5f166c2bfbaf9ba0de69da0d411288f437a9
Author:     Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
AuthorDate: Fri May 7 01:39:47 2021 +0000
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Mon May 10 18:35:46 2021 +0100

    optee: enable OPTEE_SMC_SEC_CAP_MEMREF_NULL capability
    
    OP-TEE mediator already have support for NULL memory references. It
    was added in patch 0dbed3ad336 ("optee: allow plain TMEM buffers with
    NULL address"). But it does not propagate
    OPTEE_SMC_SEC_CAP_MEMREF_NULL capability flag to a guest, so well
    behaving guest can't use this feature.
    
    Note: linux optee driver honors this capability flag when handling
    buffers from userspace clients, but ignores it when working with
    internal calls. For instance, __optee_enumerate_devices() function
    uses NULL argument to get buffer size hint from OP-TEE. This was the
    reason, why "optee: allow plain TMEM buffers with NULL address" was
    introduced in the first place.
    
    This patch adds the mentioned capability to list of known
    capabilities. From Linux point of view it means that userspace clients
    can use this feature, which is confirmed by OP-TEE test suite:
    
    * regression_1025 Test memref NULL and/or 0 bytes size
    o regression_1025.1 Invalid NULL buffer memref registration
      regression_1025.1 OK
    o regression_1025.2 Input/Output MEMREF Buffer NULL - Size 0 bytes
      regression_1025.2 OK
    o regression_1025.3 Input MEMREF Buffer NULL - Size non 0 bytes
      regression_1025.3 OK
    o regression_1025.4 Input MEMREF Buffer NULL over PTA invocation
      regression_1025.4 OK
      regression_1025 OK
    
    Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
    Acked-by: Julien Grall <jgrall@xxxxxxxxxx>
---
 xen/arch/arm/tee/optee.c            | 3 ++-
 xen/include/asm-arm/tee/optee_smc.h | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/tee/optee.c b/xen/arch/arm/tee/optee.c
index 980eebe847..345361566e 100644
--- a/xen/arch/arm/tee/optee.c
+++ b/xen/arch/arm/tee/optee.c
@@ -96,7 +96,8 @@
 #define OPTEE_KNOWN_NSEC_CAPS OPTEE_SMC_NSEC_CAP_UNIPROCESSOR
 #define OPTEE_KNOWN_SEC_CAPS (OPTEE_SMC_SEC_CAP_HAVE_RESERVED_SHM | \
                               OPTEE_SMC_SEC_CAP_UNREGISTERED_SHM | \
-                              OPTEE_SMC_SEC_CAP_DYNAMIC_SHM)
+                              OPTEE_SMC_SEC_CAP_DYNAMIC_SHM | \
+                              OPTEE_SMC_SEC_CAP_MEMREF_NULL)
 
 enum optee_call_state {
     OPTEE_CALL_NORMAL,
diff --git a/xen/include/asm-arm/tee/optee_smc.h 
b/xen/include/asm-arm/tee/optee_smc.h
index d568bb2fe1..2f5c702326 100644
--- a/xen/include/asm-arm/tee/optee_smc.h
+++ b/xen/include/asm-arm/tee/optee_smc.h
@@ -244,6 +244,9 @@
  */
 #define OPTEE_SMC_SEC_CAP_DYNAMIC_SHM          (1 << 2)
 
+/* Secure world supports Shared Memory with a NULL reference */
+#define OPTEE_SMC_SEC_CAP_MEMREF_NULL          (1 << 4)
+
 #define OPTEE_SMC_FUNCID_EXCHANGE_CAPABILITIES 9
 #define OPTEE_SMC_EXCHANGE_CAPABILITIES \
        OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_EXCHANGE_CAPABILITIES)
--
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