| Message ID | 20230731121536.934239-13-jens.wiklander@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Xen FF-A mediator | expand |
Hi Jens, > On 31 Jul 2023, at 14:15, Jens Wiklander <jens.wiklander@linaro.org> wrote: > > Adds comments with a list of unsupported FF-A interfaces and limitations > in the implemented FF-A interfaces. > > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org> > Reviewed-by: Henry Wang <Henry.Wang@arm.com> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> Cheers Bertrand > --- > v10->v11 > - No changes > --- > xen/arch/arm/tee/ffa.c | 31 +++++++++++++++++++++++++++++++ > 1 file changed, 31 insertions(+) > > diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c > index eb4a58fec470..cfbabec81dd2 100644 > --- a/xen/arch/arm/tee/ffa.c > +++ b/xen/arch/arm/tee/ffa.c > @@ -13,6 +13,37 @@ > * https://developer.arm.com/documentation/den0077/e > * TEEC-1.0C: TEE Client API Specification version 1.0c available at > * https://globalplatform.org/specs-library/tee-client-api-specification/ > + * > + * Notes on the the current implementation. > + * > + * Unsupported FF-A interfaces: > + * o FFA_MSG_POLL and FFA_MSG_SEND - deprecated in FF-A-1.1-REL0 > + * o FFA_MEM_RETRIEVE_* - Used when sharing memory from an SP to a VM > + * o FFA_MEM_DONATE_* and FFA_MEM_LEND_* - Used when tranferring ownership > + * or access of a memory region > + * o FFA_MSG_SEND2 and FFA_MSG_WAIT - Used for indirect messaging > + * o FFA_MSG_YIELD > + * o FFA_INTERRUPT - Used to report preemption > + * o FFA_RUN > + * > + * Limitations in the implemented FF-A interfaces: > + * o FFA_RXTX_MAP_*: > + * - Maps only one 4k page as RX and TX buffers > + * - Doesn't support forwarding this call on behalf of an endpoint > + * o FFA_MEM_SHARE_*: only supports sharing > + * - from a VM to an SP > + * - with one borrower > + * - with the memory transaction descriptor in the RX/TX buffer > + * - normal memory > + * - at most 512 kB large memory regions > + * - at most 32 shared memory regions per guest > + * o FFA_MSG_SEND_DIRECT_REQ: > + * - only supported from a VM to an SP > + * > + * There are some large locked sections with ffa_tx_buffer_lock and > + * ffa_rx_buffer_lock. Especially the ffa_tx_buffer_lock spinlock used > + * around share_shm() is a very large locked section which can let one VM > + * affect another VM. > */ > > #include <xen/bitops.h> > -- > 2.34.1 >
diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c index eb4a58fec470..cfbabec81dd2 100644 --- a/xen/arch/arm/tee/ffa.c +++ b/xen/arch/arm/tee/ffa.c @@ -13,6 +13,37 @@ * https://developer.arm.com/documentation/den0077/e * TEEC-1.0C: TEE Client API Specification version 1.0c available at * https://globalplatform.org/specs-library/tee-client-api-specification/ + * + * Notes on the the current implementation. + * + * Unsupported FF-A interfaces: + * o FFA_MSG_POLL and FFA_MSG_SEND - deprecated in FF-A-1.1-REL0 + * o FFA_MEM_RETRIEVE_* - Used when sharing memory from an SP to a VM + * o FFA_MEM_DONATE_* and FFA_MEM_LEND_* - Used when tranferring ownership + * or access of a memory region + * o FFA_MSG_SEND2 and FFA_MSG_WAIT - Used for indirect messaging + * o FFA_MSG_YIELD + * o FFA_INTERRUPT - Used to report preemption + * o FFA_RUN + * + * Limitations in the implemented FF-A interfaces: + * o FFA_RXTX_MAP_*: + * - Maps only one 4k page as RX and TX buffers + * - Doesn't support forwarding this call on behalf of an endpoint + * o FFA_MEM_SHARE_*: only supports sharing + * - from a VM to an SP + * - with one borrower + * - with the memory transaction descriptor in the RX/TX buffer + * - normal memory + * - at most 512 kB large memory regions + * - at most 32 shared memory regions per guest + * o FFA_MSG_SEND_DIRECT_REQ: + * - only supported from a VM to an SP + * + * There are some large locked sections with ffa_tx_buffer_lock and + * ffa_rx_buffer_lock. Especially the ffa_tx_buffer_lock spinlock used + * around share_shm() is a very large locked section which can let one VM + * affect another VM. */ #include <xen/bitops.h>