Re: [PATCH v11 3/7] firmware: arm_rmm: Move RSI support out of arch/arm64

On Mon, 14 Sep 2026 11:35:07 +0530
"Aneesh Kumar K.V (Arm)" [off-list ref] wrote:

The RSI SMCCC function IDs describe a firmware ABI and are not arm64
architecture specific definitions. Follow-up changes need to use them from
non-arch code, including drivers/firmware/smccc and the Arm CCA guest
driver.

Move the complete Realm Service Interface (RSI) implementation from
arch/arm64 to drivers/firmware/arm_rmm. The RSI SMCCC definitions and
command helpers are also moved to include/linux so they can be shared by
architecture code and firmware or driver code. This also keeps the
firmware interface outside architecture code, as requested [1].

[1] https://lore.kernel.org/all/agsNO9cc7H-b0H8L@willie-the-truck (local)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>

Moving the code makes sense and indeed that is what the patch does so
Reviewed-by: Jonathan Cameron <redacted>

Trivial gripe about the original code inline.

 
+static inline int rsi_set_memory_range(phys_addr_t start, phys_addr_t end,
+				       enum ripas state, unsigned long flags)
+{
+	unsigned long ret;
+	phys_addr_t top;
+
+	while (start != end) {
+		ret = rsi_set_addr_range_state(start, end, state, flags, &top);
+		if (ret || top < start || top > end)

Obviously this is just code movement, but why eat the error value that
rsi_set_addr_range_state() returns? 

+			return -EINVAL;
+		start = top;
+	}
+
+	return 0;
+}