[PATCH 2/2] lib: utils: Use SBI_DOMAIN_MMIO to check MMIO device permissions

Samuel Holland samuel.holland at sifive.com
Fri Nov 21 11:37:52 PST 2025


Drivers or platforms may create memory regions with the MMIO flag set
that contain S-mode-accessible MMIO devices. This is strictly correct
and should be allowed, along with the existing default case of
S-mode-accessible MMIO devices appearing in non-MMIO memory regions.
When passed SBI_DOMAIN_MMIO, sbi_domain_check_addr() will perform the
correct set of permission checks.

Signed-off-by: Samuel Holland <samuel.holland at sifive.com>
---

 lib/utils/fdt/fdt_fixup.c             | 2 +-
 lib/utils/mpxy/fdt_mpxy_rpmi_sysmsi.c | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/utils/fdt/fdt_fixup.c b/lib/utils/fdt/fdt_fixup.c
index f3fe8af9..b0ed20c8 100644
--- a/lib/utils/fdt/fdt_fixup.c
+++ b/lib/utils/fdt/fdt_fixup.c
@@ -185,7 +185,7 @@ static void fdt_domain_based_fixup_one(void *fdt, int nodeoff)
 		return;
 
 	if (!sbi_domain_check_addr(dom, reg_addr, dom->next_mode,
-				    SBI_DOMAIN_READ | SBI_DOMAIN_WRITE)) {
+				    SBI_DOMAIN_READ | SBI_DOMAIN_WRITE | SBI_DOMAIN_MMIO)) {
 		rc = fdt_open_into(fdt, fdt, fdt_totalsize(fdt) + 32);
 		if (rc < 0)
 			return;
diff --git a/lib/utils/mpxy/fdt_mpxy_rpmi_sysmsi.c b/lib/utils/mpxy/fdt_mpxy_rpmi_sysmsi.c
index 94a5af8c..1dcc049e 100644
--- a/lib/utils/mpxy/fdt_mpxy_rpmi_sysmsi.c
+++ b/lib/utils/mpxy/fdt_mpxy_rpmi_sysmsi.c
@@ -57,7 +57,8 @@ static int mpxy_rpmi_sysmis_xfer(void *context, struct mbox_chan *chan,
 			sys_msi_address |= ((u64)le32_to_cpu(((u32 *)xfer->tx)[2])) << 32;
 			if (!sbi_domain_check_addr_range(sbi_domain_thishart_ptr(),
 							 sys_msi_address, 0x4, PRV_S,
-							 SBI_DOMAIN_READ | SBI_DOMAIN_WRITE)) {
+							 SBI_DOMAIN_READ | SBI_DOMAIN_WRITE |
+							 SBI_DOMAIN_MMIO)) {
 				((u32 *)xfer->rx)[0] = cpu_to_le32(RPMI_ERR_INVALID_ADDR);
 				args->rx_data_len = sizeof(u32);
 				break;
-- 
2.47.2




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