Hi Bertrand,
On Tue, Feb 3, 2026 at 6:38 PM Bertrand Marquis
<[email protected]> wrote:
>
> MSG_SEND2 and direct request validation failures are silent, making it
> hard to diagnose invalid IDs, oversized messages, or unsupported
> destination types.
>
> Add debug logs for parameter validation failures:
> - invalid endpoint IDs
> - oversized messages
> - unsupported destination types
> - invalid sender/receiver combinations
> - ratelimit MSG_SEND2 busy failures to avoid log flooding
>
> No functional changes.
>
> Signed-off-by: Bertrand Marquis <[email protected]>
> ---
> xen/arch/arm/tee/ffa_msg.c | 45 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
>
> diff --git a/xen/arch/arm/tee/ffa_msg.c b/xen/arch/arm/tee/ffa_msg.c
> index 928f269f6c3a..cc273c9a8e80 100644
> --- a/xen/arch/arm/tee/ffa_msg.c
> +++ b/xen/arch/arm/tee/ffa_msg.c
> @@ -4,6 +4,7 @@
> */
>
> #include <xen/const.h>
> +#include <xen/lib.h>
> #include <xen/sizes.h>
> #include <xen/types.h>
>
> @@ -100,6 +101,7 @@ void ffa_handle_msg_send_direct_req(struct cpu_user_regs
> *regs, uint32_t fid)
> if ( !ffa_fw_supports_fid(fid) )
> {
> ret = FFA_RET_NOT_SUPPORTED;
> + gdprintk(XENLOG_DEBUG, "ffa: direct req fid %#x not supported\n",
> fid);
> goto out;
> }
>
> @@ -108,6 +110,9 @@ void ffa_handle_msg_send_direct_req(struct cpu_user_regs
> *regs, uint32_t fid)
> (src_dst & GENMASK(15,0)) == ffa_get_vm_id(d) )
> {
> ret = FFA_RET_INVALID_PARAMETERS;
> + gdprintk(XENLOG_DEBUG,
> + "ffa: direct req invalid src/dst %#x\n",
> + (uint32_t)src_dst);
> goto out;
> }
>
> @@ -115,6 +120,9 @@ void ffa_handle_msg_send_direct_req(struct cpu_user_regs
> *regs, uint32_t fid)
> if ( !FFA_ID_IS_SECURE(src_dst & GENMASK(15,0)) )
> {
> ret = FFA_RET_NOT_SUPPORTED;
> + gdprintk(XENLOG_DEBUG,
> + "ffa: direct req to non-secure dst %#x\n",
> + (uint32_t)(src_dst & GENMASK(15, 0)));
> goto out;
> }
>
> @@ -166,7 +174,12 @@ static int32_t ffa_msg_send2_vm(uint16_t dst_id, const
> void *src_buf,
> /* This is also checking that dest is not src */
> ret = ffa_endpoint_domain_lookup(dst_id, &dst_d, &dst_ctx);
> if ( ret )
> + {
> + gdprintk(XENLOG_DEBUG,
> + "ffa: msg_send2 lookup failed: dst %#x ret %d\n",
> + dst_id, ret);
> return ret;
> + }
>
> /* This also checks that destination has set a Rx buffer */
> ret = ffa_rx_acquire(dst_ctx , &rx_buf, &rx_size);
> @@ -199,6 +212,12 @@ static int32_t ffa_msg_send2_vm(uint16_t dst_id, const
> void *src_buf,
> /* receiver rx buffer will be released by the receiver*/
>
> out_unlock:
> + if ( ret )
> + {
> + if ( ret != FFA_RET_BUSY || printk_ratelimit() )
Shouldn't this be && ?
Cheers,
Jens
> + gdprintk(XENLOG_DEBUG, "ffa: msg_send2 to %#x failed: %d\n",
> + dst_id, ret);
> + }
> rcu_unlock_domain(dst_d);
> if ( !ret )
> ffa_raise_rx_buffer_full(dst_d);
> @@ -226,7 +245,11 @@ int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs)
>
> ret = ffa_tx_acquire(src_ctx, &tx_buf, &tx_size);
> if ( ret != FFA_RET_OK )
> + {
> + gdprintk(XENLOG_DEBUG,
> + "ffa: msg_send2 TX acquire failed: %d\n", ret);
> return ret;
> + }
>
> /* create a copy of the message header */
> memcpy(&src_msg, tx_buf, sizeof(src_msg));
> @@ -238,6 +261,9 @@ int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs)
> dst_id == ffa_get_vm_id(src_d) )
> {
> ret = FFA_RET_INVALID_PARAMETERS;
> + gdprintk(XENLOG_DEBUG,
> + "ffa: msg_send2 invalid src/dst src %#x dst %#x\n",
> + src_id, dst_id);
> goto out;
> }
>
> @@ -246,6 +272,9 @@ int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs)
> if (src_msg.msg_offset < sizeof(struct ffa_part_msg_rxtx_1_1))
> {
> ret = FFA_RET_INVALID_PARAMETERS;
> + gdprintk(XENLOG_DEBUG,
> + "ffa: msg_send2 invalid msg_offset %u (v1.1)\n",
> + src_msg.msg_offset);
> goto out;
> }
> /* Set uuid to Nil UUID for v1.1 guests */
> @@ -255,6 +284,9 @@ int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs)
> else if ( src_msg.msg_offset < sizeof(struct ffa_part_msg_rxtx_1_2) )
> {
> ret = FFA_RET_INVALID_PARAMETERS;
> + gdprintk(XENLOG_DEBUG,
> + "ffa: msg_send2 invalid msg_offset %u (v1.2)\n",
> + src_msg.msg_offset);
> goto out;
> }
>
> @@ -263,6 +295,9 @@ int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs)
> src_msg.msg_size > (tx_size - src_msg.msg_offset) )
> {
> ret = FFA_RET_INVALID_PARAMETERS;
> + gdprintk(XENLOG_DEBUG,
> + "ffa: msg_send2 invalid msg_size %u offset %u tx %zu\n",
> + src_msg.msg_size, src_msg.msg_offset, tx_size);
> goto out;
> }
>
> @@ -272,6 +307,8 @@ int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs)
> if ( !ffa_fw_supports_fid(FFA_MSG_SEND2) )
> {
> ret = FFA_RET_NOT_SUPPORTED;
> + gdprintk(XENLOG_DEBUG,
> + "ffa: msg_send2 to SP not supported\n");
> goto out;
> }
> /*
> @@ -288,6 +325,8 @@ int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs)
>
> ret = ffa_simple_call(FFA_MSG_SEND2,
> ((uint32_t)ffa_get_vm_id(src_d)) << 16, 0, 0,
> 0);
> + if ( ret )
> + gdprintk(XENLOG_DEBUG, "ffa: msg_send2 to SP failed: %d\n", ret);
> }
> else if ( IS_ENABLED(CONFIG_FFA_VM_TO_VM) )
> {
> @@ -295,7 +334,11 @@ int32_t ffa_handle_msg_send2(struct cpu_user_regs *regs)
> ret = ffa_msg_send2_vm(dst_id, tx_buf, &src_msg);
> }
> else
> + {
> ret = FFA_RET_INVALID_PARAMETERS;
> + gdprintk(XENLOG_DEBUG,
> + "ffa: msg_send2 to VM disabled (dst %#x)\n", dst_id);
> + }
>
> out:
> ffa_tx_release(src_ctx);
> @@ -311,6 +354,7 @@ void ffa_handle_run(struct cpu_user_regs *regs, uint32_t
> fid)
> if ( !ffa_fw_supports_fid(fid) )
> {
> ret = FFA_RET_NOT_SUPPORTED;
> + gdprintk(XENLOG_DEBUG, "ffa: run fid %#x not supported\n", fid);
> goto out;
> }
>
> @@ -322,6 +366,7 @@ void ffa_handle_run(struct cpu_user_regs *regs, uint32_t
> fid)
> if ( !FFA_ID_IS_SECURE(dst >> 16) )
> {
> ret = FFA_RET_NOT_SUPPORTED;
> + gdprintk(XENLOG_DEBUG, "ffa: run to non-secure dst %#x\n", dst);
> goto out;
> }
>
> --
> 2.50.1 (Apple Git-155)
>
