Commit 82a8daae authored by Marc Bonnici's avatar Marc Bonnici Committed by Sudeep Holla
Browse files

firmware: arm_ffa: Add support for MEM_LEND 

As part of the FF-A spec, an endpoint is allowed to transfer access of,
or lend, a memory region to one or more borrowers.

Extend the existing memory sharing implementation to support
FF-A MEM_LEND functionality and expose this to other kernel drivers.

Note that upon a successful MEM_LEND request the caller must ensure that
the memory region specified is not accessed until a successful
MEM_RECALIM call has been made. On systems with a hypervisor present
this will been enforced, however on systems without a hypervisor the
responsibility falls to the calling kernel driver to prevent access.

Link: https://lore.kernel.org/r/20211015165742.2513065-1-marc.bonnici@arm.com


Reviewed-by: default avatarJens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: default avatarMarc Bonnici <marc.bonnici@arm.com>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 8e3f9da6

drivers/firmware/arm_ffa/driver.c

+17 −0
Original line number Diff line number Diff line
@@ -613,6 +613,22 @@ ffa_memory_share(struct ffa_device *dev, struct ffa_mem_ops_args *args) 
	return ffa_memory_ops(FFA_FN_NATIVE(MEM_SHARE), args);

}



static int

ffa_memory_lend(struct ffa_device *dev, struct ffa_mem_ops_args *args)

{

	/* Note that upon a successful MEM_LEND request the caller

	 * must ensure that the memory region specified is not accessed

	 * until a successful MEM_RECALIM call has been made.

	 * On systems with a hypervisor present this will been enforced,

	 * however on systems without a hypervisor the responsibility

	 * falls to the calling kernel driver to prevent access.

	 */

	if (dev->mode_32bit)

		return ffa_memory_ops(FFA_MEM_LEND, args);



	return ffa_memory_ops(FFA_FN_NATIVE(MEM_LEND), args);

}



static const struct ffa_dev_ops ffa_ops = {

	.api_version_get = ffa_api_version_get,

	.partition_info_get = ffa_partition_info_get,
@@ -620,6 +636,7 @@ static const struct ffa_dev_ops ffa_ops = { 
	.sync_send_receive = ffa_sync_send_receive,

	.memory_reclaim = ffa_memory_reclaim,

	.memory_share = ffa_memory_share,

	.memory_lend = ffa_memory_lend,

};



const struct ffa_dev_ops *ffa_dev_ops_get(struct ffa_device *dev)

include/linux/arm_ffa.h

+2 −0
Original line number Diff line number Diff line
@@ -262,6 +262,8 @@ struct ffa_dev_ops { 
	int (*memory_reclaim)(u64 g_handle, u32 flags);

	int (*memory_share)(struct ffa_device *dev,

			    struct ffa_mem_ops_args *args);

	int (*memory_lend)(struct ffa_device *dev,

			   struct ffa_mem_ops_args *args);

};



#endif /* _LINUX_ARM_FFA_H */