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firmware: arm_ffa: Add support for MEM_LEND

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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: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Marc Bonnici 2021-10-15 17:57:42 +01:00 committed by Sudeep Holla
parent 8e3f9da608
commit 82a8daaecf
2 changed files with 19 additions and 0 deletions
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17
drivers/firmware/arm_ffa/driver.c
View File

@ -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)

2
include/linux/arm_ffa.h
View File

@ -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 */