feat(rmmd): route MEC refresh via FIRME

Use FIRME_MEC_REFRESH as the provider for the RMM_MEC_REFRESH command
and remove replace the existing plat_rmmd_mecid_key_update() hook.

BREAKING-CHANGE: plat_rmmd_mecid_key_update() is deprecated for MEC
refresh flows and has been dropped. Platforms that currently implement
plat_rmmd_mecid_key_update() for MECID key refresh must migrate that
logic to plat_firme_mec_refresh(), including converting return values to
FIRME status codes.

Change-Id: I79985e0f7280b31e1fd149ef1e51bc9cf4b5a6cb
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>

6 files changed, 22 insertions, 75 deletions

diff --git a/docs/porting-guide.rst b/docs/porting-guide.rst
index 9dcb72f93..30d5f751c 100644
--- a/docs/porting-guide.rst
+++ b/docs/porting-guide.rst
@@ -2365,24 +2365,33 @@ RMM image and stores it in the area specified by manifest.
 
 When ENABLE_RMM is disabled, this function is not used.
 
-Function : plat_rmmd_mecid_key_update() [when ENABLE_RMM == 1]
+Function : plat_firme_mec_refresh() [when FIRME_SUPPORT == 1]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 ::
 
-    Argument : uint16_t, unsigned int
+    Argument : uint16_t, uint8_t
     Return   : int
 
-This function is invoked by BL31's RMMD when there is a request from the RMM
-monitor to update the tweak for the encryption key associated to a MECID.
+This function is invoked by BL31's FIRME MECID management service when there is
+a request to refresh the Memory Encryption Context (MEC) associated with a
+MECID.
 
-The first parameter (``uint16_t mecid``) contains the MECID for which the
-encryption key is to be updated. The second argument specifies the reason
-for key update. Possible values are: 0 - Realm creation, 1 - Realm destruction.
+The first parameter (``uint16_t mecid``) contains the MECID whose associated
+MEC is to be refreshed. The second parameter (``uint8_t reason``) specifies the
+reason for the refresh. Possible values are:
+``MEC_REFRESH_REASON_REALM_CREATE`` for Realm creation and
+``MEC_REFRESH_REASON_REALM_DESTROY`` for Realm destruction.
 
-Return value is 0 upon success and -EFAULT otherwise.
+The FIRME MECID management service validates that FEAT_MEC is supported and
+that the MECID fits within the common MECID width before calling this function.
 
-This function needs to be implemented by a platform if it enables RME.
+The function returns a FIRME status code. It should return ``FIRME_SUCCESS`` on
+success, or an appropriate negative FIRME error code such as
+``FIRME_INVALID_PARAMETERS``, ``FIRME_DENIED`` or ``FIRME_RETRY`` on failure.
+
+This function needs to be implemented by a platform if it enables FIRME support
+and advertises the FIRME MECID management service.
 
 Function : plat_rmmd_reserve_memory() [when ENABLE_RMM == 1]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h
index 4d4682cd6..b953c2893 100644
--- a/include/plat/common/platform.h
+++ b/include/plat/common/platform.h
@@ -409,7 +409,6 @@ int plat_rmmd_el3_token_sign_push_req(
 int plat_rmmd_el3_token_sign_pull_resp(struct el3_token_sign_response *resp);
 size_t plat_rmmd_get_el3_rmm_shared_mem(uintptr_t *shared);
 int plat_rmmd_load_manifest(struct rmm_manifest *manifest);
-int plat_rmmd_mecid_key_update(uint16_t mecid, unsigned int reason);
 uintptr_t plat_rmmd_reserve_memory(size_t size, unsigned long alignment);
 
 /* The following 4 functions are to be implemented if
diff --git a/plat/arm/board/fvp/fvp_common.c b/plat/arm/board/fvp/fvp_common.c
index 4aafc0530..3733eee30 100644
--- a/plat/arm/board/fvp/fvp_common.c
+++ b/plat/arm/board/fvp/fvp_common.c
@@ -1066,7 +1066,7 @@ int plat_rmmd_load_manifest(struct rmm_manifest *manifest)
 /*
  * Update encryption key associated with @mecid.
  */
-int plat_rmmd_mecid_key_update(uint16_t mecid, unsigned int reason)
+int plat_firme_mec_refresh(uint16_t mecid, uint8_t reason)
 {
 	/*
 	 * FVP does not provide an interface to change the encryption key associated
@@ -1074,9 +1074,4 @@ int plat_rmmd_mecid_key_update(uint16_t mecid, unsigned int reason)
 	 */
 	return 0;
 }
-
-int plat_firme_mec_refresh(uint16_t mecid, uint8_t reason)
-{
-	return 0;
-}
 #endif /* ENABLE_RMM */
diff --git a/plat/arm/board/neoverse_rd/platform/rdv3/rdv3_common.c b/plat/arm/board/neoverse_rd/platform/rdv3/rdv3_common.c
index aa4cec63e..ad25d570d 100644
--- a/plat/arm/board/neoverse_rd/platform/rdv3/rdv3_common.c
+++ b/plat/arm/board/neoverse_rd/platform/rdv3/rdv3_common.c
@@ -189,15 +189,6 @@ int plat_rmmd_load_manifest(struct rmm_manifest *manifest)
 /*
  * Update encryption key associated with @mecid.
  */
-int plat_rmmd_mecid_key_update(uint16_t mecid, unsigned int reason)
-{
-	/*
-	 * RDV3 does not support FEAT_MEC.
-	 * This empty hook is for compilation to succeed.
-	 */
-	return 0;
-}
-
 int plat_firme_mec_refresh(uint16_t mecid, uint8_t reason)
 {
 	/*
diff --git a/plat/qemu/common/qemu_common.c b/plat/qemu/common/qemu_common.c
index 97625bd49..3bdc02f4d 100644
--- a/plat/qemu/common/qemu_common.c
+++ b/plat/qemu/common/qemu_common.c
@@ -761,15 +761,6 @@ int plat_rmmd_load_manifest(struct rmm_manifest *manifest)
 /*
  * Update encryption key associated with @mecid.
  */
-int plat_rmmd_mecid_key_update(uint16_t mecid, unsigned int reason)
-{
-	/*
-	 * QEMU does not provide an interface to change the encryption key
-	 * associated with MECID. Hence always return success.
-	 */
-	return 0;
-}
-
 int plat_firme_mec_refresh(uint16_t mecid, uint8_t reason)
 {
 	/*
diff --git a/services/std_svc/rmmd/rmmd_main.c b/services/std_svc/rmmd/rmmd_main.c
index 521bb9e16..c648a452a 100644
--- a/services/std_svc/rmmd/rmmd_main.c
+++ b/services/std_svc/rmmd/rmmd_main.c
@@ -32,6 +32,7 @@
 #include <plat/common/platform.h>
 #include <platform_def.h>
 #include <services/rmmd_svc.h>
+#include <services/firme_svc.h>
 #include <smccc_helpers.h>
 #include <lib/extensions/sme.h>
 #include <lib/extensions/sve.h>
@@ -455,46 +456,6 @@ static int rmm_el3_ifc_get_feat_register(uint64_t feat_reg_idx,
 	return E_RMM_OK;
 }
 
-/*
- * Update encryption key associated with mecid included in x1.
- */
-static int rmmd_mecid_key_update(uint64_t x1)
-{
-	uint64_t mecid_width, mecid_width_mask;
-	uint16_t mecid;
-	unsigned int reason;
-	int ret;
-
-	/*
-	 * Check whether FEAT_MEC is supported by the hardware. If not, return
-	 * unknown SMC.
-	 */
-	if (is_feat_mec_supported() == false) {
-		return E_RMM_UNK;
-	}
-
-	/*
-	 * Check whether the mecid parameter is at most MECIDR_EL2.MECIDWidthm1 + 1
-	 * in length.
-	 */
-	mecid_width = ((read_mecidr_el2() >> MECIDR_EL2_MECIDWidthm1_SHIFT) &
-		MECIDR_EL2_MECIDWidthm1_MASK) + 1UL;
-	mecid_width_mask = ((1UL << mecid_width) - 1UL);
-
-	mecid = (x1 >> MECID_SHIFT) & MECID_MASK;
-	if ((mecid & ~mecid_width_mask) != 0U) {
-		return E_RMM_INVAL;
-	}
-
-	reason = (x1 >> MEC_REFRESH_REASON_SHIFT) & MEC_REFRESH_REASON_MASK;
-	ret = plat_rmmd_mecid_key_update(mecid, reason);
-
-	if (ret != 0) {
-		return E_RMM_UNK;
-	}
-	return E_RMM_OK;
-}
-
 /*******************************************************************************
  * This function handles RMM-EL3 interface SMCs
  ******************************************************************************/
@@ -585,7 +546,8 @@ uint64_t rmmd_rmm_el3_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2,
 		rmmd_rmm_sync_exit(x1);
 	}
 	case RMM_MEC_REFRESH:
-		ret = rmmd_mecid_key_update(x1);
+		ret = firme_handler(FIRME_MEC_REFRESH_FID, x1, x2, x3, x4,
+				    cookie, handle, flags);
 		SMC_RET1(handle, ret);
 	default:
 		WARN("RMMD: Unsupported RMM-EL3 call 0x%08x\n", smc_fid);