Hi Mostafa,

On 2026/2/27 PM10:39, Mostafa Saleh wrote:
On Sat, Feb 21, 2026 at 06:02:28PM +0800, Tao Tang wrote:
When decoding a Stream Table Entry (STE) from the Secure stream table
that enables stage-2 translation, verify that the SMMU implementation
advertises Secure stage-2 support via S_IDR1.SEL2. If stage-2 is
requested but S_IDR1.SEL2 is 0, mark the STE as ILLEGAL.

This implements the requirement from the Arm SMMUv3 architecture
specification (IHI 0070G.b, Section 5.2, Page 218) that a Secure STE
with stage-2 enabled is only valid when the implementation supports
Secure stage-2 translation.

Signed-off-by: Tao Tang <[email protected]>
---
  hw/arm/smmuv3.c | 10 ++++++++++
  1 file changed, 10 insertions(+)

diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index 2192bec2368..d011357253e 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -623,6 +623,16 @@ static int decode_ste(SMMUv3State *s, SMMUTransCfg *cfg,
          if (ret) {
              goto bad_ste;
          }
+
+        /*
+         * Stage 2 is implemented but Secure stage 2 is not supported while
+         * STE is from Secure stream table. STE is ILLEGAL in this case
+         * according to (IHI 0070G.b) 5.2 STE, Stream Table Entry, Page 218.
+         */
+        if ((cfg->sec_sid == SMMU_SEC_SID_S) &&
+            !(FIELD_EX32(s->bank[SMMU_SEC_SID_S].idr[1], S_IDR1, SEL2))) {
+            goto bad_ste;
+        }
The IDR is not currently set, we can just safely return bad_ste for
“SMMU_SEC_SID_S”, no need to complicate things until SEL2 is supported.


Agreed. I’ll simplify this to unconditionally treat Secure STE requesting stage-2 as ILLEGAL, and revisit the SEL2 check once SEL2 support is implemented.


Thanks,
Mostafa


Best regards,

Tao


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