On 7/11/2023 7:36 AM, Nishant Sharma wrote:
> From: Achin Gupta <achin.gupta@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.gupta@arm.com>
> Signed-off-by: Nishant Sharma <nishant.sharma@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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