On 7/11/2023 7:36 AM, Nishant Sharma wrote:
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;
If I am reading this correctly, this SVC macro does not get added until patch 18. We need it here, otherwise bisecting to this commit will have a build break, right? Thanks, Oliver
+ 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.
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