From: Yao Xingtao <yaoxt.fnst@fujitsu.com>

Since the kernel does not check the interleave capability, a
3-way, 6-way, 12-way or 16-way region can be create normally.

Applications can access the memory of 16-way region normally because
qemu can convert hpa to dpa correctly for the power of 2 interleave
ways, after kernel implementing the check, this kind of region will
not be created any more.

For non power of 2 interleave ways, applications could not access the
memory normally and may occur some unexpected behaviors, such as
segmentation fault.

So implements this feature is needed.

Link: https://lore.kernel.org/linux-cxl/3e84b919-7631-d1db-3e1d-33000f3f3868@fujitsu.com/
Signed-off-by: Yao Xingtao <yaoxt.fnst@fujitsu.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20250203161908.145406-6-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/cxl/cxl-component-utils.c |  9 +++++++--
 hw/mem/cxl_type3.c           | 15 +++++++++++----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/hw/cxl/cxl-component-utils.c b/hw/cxl/cxl-component-utils.c
index cd116c0401..473895948b 100644
--- a/hw/cxl/cxl-component-utils.c
+++ b/hw/cxl/cxl-component-utils.c
@@ -243,8 +243,13 @@ static void hdm_init_common(uint32_t *reg_state, uint32_t *write_msk,
     ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, INTERLEAVE_4K, 1);
     ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY,
                      POISON_ON_ERR_CAP, 0);
-    ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, 3_6_12_WAY, 0);
-    ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, 16_WAY, 0);
+    if (type == CXL2_TYPE3_DEVICE) {
+        ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, 3_6_12_WAY, 1);
+        ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, 16_WAY, 1);
+    } else {
+        ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, 3_6_12_WAY, 0);
+        ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, 16_WAY, 0);
+    }
     ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, UIO, 0);
     ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY,
                      UIO_DECODER_COUNT, 0);
diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index d8b45f9bd1..6fffa21ead 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -1100,10 +1100,17 @@ static bool cxl_type3_dpa(CXLType3Dev *ct3d, hwaddr host_addr, uint64_t *dpa)
             continue;
         }
 
-        *dpa = dpa_base +
-            ((MAKE_64BIT_MASK(0, 8 + ig) & hpa_offset) |
-             ((MAKE_64BIT_MASK(8 + ig + iw, 64 - 8 - ig - iw) & hpa_offset)
-              >> iw));
+        if (iw < 8) {
+            *dpa = dpa_base +
+                ((MAKE_64BIT_MASK(0, 8 + ig) & hpa_offset) |
+                 ((MAKE_64BIT_MASK(8 + ig + iw, 64 - 8 - ig - iw) & hpa_offset)
+                  >> iw));
+        } else {
+            *dpa = dpa_base +
+                ((MAKE_64BIT_MASK(0, 8 + ig) & hpa_offset) |
+                 ((((MAKE_64BIT_MASK(ig + iw, 64 - ig - iw) & hpa_offset)
+                   >> (ig + iw)) / 3) << (ig + 8)));
+        }
 
         return true;
     }
-- 
MST