From: Achin Gupta <achin.gu...@arm.com>
An FF-A partition can map only a single RX/TX buffer pair with the
framework. The DXE MM communication driver maps its pair before
ExitBootServices is called. The OS cannot re-use this pair once it boots
subsequently and loads its own FF-A driver. This patch ensures that the
DXE MM communication driver unmaps its buffer pair when ExitBootServices
is called so that the OS can register its own pair if required.
Signed-off-by: Achin Gupta <achin.gu...@arm.com>
Signed-off-by: Nishant Sharma <nishant.sha...@arm.com>
---
ArmPkg/Include/IndustryStandard/ArmFfaSvc.h | 10 ++++
ArmPkg/Drivers/MmCommunicationDxe/MmCommunication.c | 49 ++++++++++++++++++++
2 files changed, 59 insertions(+)
diff --git a/ArmPkg/Include/IndustryStandard/ArmFfaSvc.h
b/ArmPkg/Include/IndustryStandard/ArmFfaSvc.h
index ebdf29e8d69a..f78442a465e1 100644
--- a/ArmPkg/Include/IndustryStandard/ArmFfaSvc.h
+++ b/ArmPkg/Include/IndustryStandard/ArmFfaSvc.h
@@ -122,6 +122,16 @@
(((content) & FFA_BOOT_INFO_FLAG_CONTENT_MASK) \
<< FFA_BOOT_INFO_FLAG_CONTENT_SHIFT)
+/* Fromat SP ID info. */
+#define FFA_PARTITION_ID_SHIFT 16
+#define FFA_PARTITION_ID_WIDTH 16
+#define FFA_PARTITION_ID_MASK \
+ (((1U << FFA_PARTITION_ID_WIDTH) - 1) \
+ << FFA_PARTITION_ID_SHIFT)
+#define FFA_PARTITION_ID(partid) \
+ ((partid << FFA_PARTITION_ID_SHIFT) & \
+ FFA_PARTITION_ID_MASK)
+
// Descriptor to pass boot information as per the FF-A v1.1 spec.
typedef struct {
UINT32 Name[4];
diff --git a/ArmPkg/Drivers/MmCommunicationDxe/MmCommunication.c
b/ArmPkg/Drivers/MmCommunicationDxe/MmCommunication.c
index 8a4d46e4f80a..39a1b329b9ea 100644
--- a/ArmPkg/Drivers/MmCommunicationDxe/MmCommunication.c
+++ b/ArmPkg/Drivers/MmCommunicationDxe/MmCommunication.c
@@ -43,6 +43,9 @@ STATIC ARM_MEMORY_REGION_DESCRIPTOR mNsCommBuffMemRegion;
// Notification event when virtual address map is set.
STATIC EFI_EVENT mSetVirtualAddressMapEvent;
+// Notification event when exit boot services is called.
+STATIC EFI_EVENT mExitBootServicesEvent;
+
//
// Handle to install the MM Communication Protocol
//
@@ -255,6 +258,39 @@ NotifySetVirtualAddressMap (
}
}
+/**
+ Notification callback on ExitBootServices event.
+
+ This function notifies the MM communication protocol interface on
+ ExitBootServices event and releases the FF-A RX/TX buffer.
+
+ @param Event ExitBootServices event.
+ @param Context A context when the ExitBootServices triggered.
+
+ @retval EFI_SUCCESS The function executed successfully.
+ @retval Other Some error occurred when executing this function.
+
+**/
+STATIC
+VOID
+EFIAPI
+NotifyExitBootServices (
+ IN EFI_EVENT Event,
+ IN VOID *Context
+ )
+{
+ ARM_SMC_ARGS SmcArgs = {0};
+
+ SmcArgs.Arg0 = ARM_SVC_ID_FFA_RXTX_UNMAP_AARCH32;
+ SmcArgs.Arg1 = FFA_PARTITION_ID(mFfaPartId);
+ ArmCallSmc (&SmcArgs);
+
+ // We do not bother checking the error code of the RXTX_UNMAP invocation
+ // since we did map the buffers and this call must succeed.
+ return;
+
+}
+
STATIC
EFI_STATUS
GetMmCompatibility (
@@ -452,6 +488,19 @@ MmCommunication2Initialize (
goto CleanAddedMemorySpace;
}
+ // Register notification callback when ExitBootservices is called to
+ // unregister the FF-A RX/TX buffer pair. This allows the OS to register its
+ // own buffer pair.
+ if (FixedPcdGet32 (PcdFfaEnable) != 0) {
+ Status = gBS->CreateEvent (
+ EVT_SIGNAL_EXIT_BOOT_SERVICES,
+ TPL_NOTIFY,
+ NotifyExitBootServices,
+ NULL,
+ &mExitBootServicesEvent
+ );
+ ASSERT_EFI_ERROR (Status);
+ }
// Register notification callback when virtual address is associated
// with the physical address.
// Create a Set Virtual Address Map event.
--
2.34.1
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