[PATCH 4/5] cxl/type3: add an optional mhd validation function for memory accesses

[Gregory Price]

When memory accesses are made, some MHSLD's would validate the address
is within the scope of allocated sections.  To do this, the base device
must call an optional function set by inherited devices.

Signed-off-by: Gregory Price <gregory.pr...@memverge.com>
---
 hw/mem/cxl_type3.c          | 15 +++++++++++++++
 include/hw/cxl/cxl_device.h |  3 +++
 2 files changed, 18 insertions(+)

diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index a8d4a12f3e..8e1565f2fc 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -1034,6 +1034,10 @@ void ct3_realize(PCIDevice *pci_dev, Error **errp)
             goto err_release_cdat;
         }
     }
+
+    /* Devices which inherit ct3d should initialize these after ct3_realize */
+    ct3d->mhd_access_valid = NULL;
+
     return;
 
 err_release_cdat:
@@ -1259,6 +1263,11 @@ MemTxResult cxl_type3_read(PCIDevice *d, hwaddr 
host_addr, uint64_t *data,
         return MEMTX_ERROR;
     }
 
+    if (ct3d->mhd_access_valid &&
+        !ct3d->mhd_access_valid(d, dpa_offset, size)) {
+        return MEMTX_ERROR;
+    }
+
     if (sanitize_running(&ct3d->cci)) {
         qemu_guest_getrandom_nofail(data, size);
         return MEMTX_OK;
@@ -1279,6 +1288,12 @@ MemTxResult cxl_type3_write(PCIDevice *d, hwaddr 
host_addr, uint64_t data,
     if (res) {
         return MEMTX_ERROR;
     }
+
+    if (ct3d->mhd_access_valid &&
+        !ct3d->mhd_access_valid(d, dpa_offset, size)) {
+        return MEMTX_ERROR;
+    }
+
     if (sanitize_running(&ct3d->cci)) {
         return MEMTX_OK;
     }
diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index 4ad38b689c..b1b39a9aa0 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -489,6 +489,9 @@ struct CXLType3Dev {
         uint8_t num_regions; /* 0-8 regions */
         CXLDCDRegion regions[DCD_MAX_REGION_NUM];
     } dc;
+
+    /* Multi-headed Device */
+    bool (*mhd_access_valid)(PCIDevice *d, uint64_t addr, unsigned int size);
 };
 
 #define TYPE_CXL_TYPE3 "cxl-type3"
-- 
2.39.1