Merge pull request #306 from ved-rivos/0502

Add a helper to extract attributes

iommu_ref_model/README.md

@@ -142,6 +142,10 @@ This function when invoked causes the IOMMU to process a command from the comman
 function acts like a "clock" and in each invocation processes one command. If multiple command
 processing is required then the function should be invoked for each command.
 
+9. **`void get_attribs_from_req(hb_to_iommu_req_t *req, uint8_t *read, uint8_t *write, uint8_t *exec, uint8_t *priv)`**
+
+This function is used to extract the read, write, execute, and privilege
+attributes from the the request.
 
 # Libtables functions
 The following functions are provided by the libtables to build memory resident data structures.

iommu_ref_model/libiommu/include/iommu_ref_api.h

@@ -28,5 +28,7 @@ extern void process_commands(void);
 
 extern void iommu_to_hb_do_global_observability_sync(uint8_t PR, uint8_t PW);
 extern void send_msg_iommu_to_hb(ats_msg_t *prgr);
+extern void get_attribs_from_req(hb_to_iommu_req_t *req, uint8_t *read,
+                                 uint8_t *write, uint8_t *exec, uint8_t *priv);
 
 #endif // __IOMMU_REF_API_H__

iommu_ref_model/libiommu/src/iommu_translate.c

@@ -68,32 +68,8 @@ iommu_translate_iova(
     // Has to be one of the valid ttypes - this only for debug - not architectural
     if ( TTYP == TTYPE_NONE ) *((char *)0) = 0;
 
-    is_read = ( req->tr.read_writeAMO == READ ) ? 1 : 0;
-    is_write = ( req->tr.read_writeAMO == WRITE ) ?  1 : 0;
-
-    // The No Write flag, when Set, indicates that the Function is requesting read-only 
-    // access for this translation.
-    // The TA (IOMMU) may ignore the No Write Flag, however, if the TA responds with a 
-    // translation marked as read-only then the Function must not issue Memory Write 
-    // transactions using that translation. In this case, the Function may issue another
-    // translation request with the No Write flag Clear, which may result in a new 
-    // translation completion with or without the W (Write) bit Set.
-    // Upon receiving a Translation Request with the NW flag Clear, TAs are permitted to
-    // mark the associated pages dirty. Functions MUST not issue such Requests 
-    // unless they have been given explicit write permission.
-    // Note ATS Translation requests are read - so read_writeAMO is READ for these requests
-    is_write = ( (req->tr.at == ADDR_TYPE_PCIE_ATS_TRANSLATION_REQUEST) && 
-                 (req->no_write == 0) ) ? 1 : is_write; 
-
-    // If a Translation Request has a PASID, the Untranslated Address Field is an address 
-    // within the process address space indicated by the PASID field.
-    // If a Translation Request has a PASID with either the Privileged Mode Requested 
-    // or Execute Requested bit Set, these may be used in constructing the Translation 
-    // Completion Data Entry.  The PASID Extended Capability indicates whether a Function
-    // supports and is enabled to send and receive TLPs with the PASID.
-    is_exec = ( (is_read && req->exec_req &&
-                (req->tr.at == ADDR_TYPE_UNTRANSLATED || req->pid_valid)) ) ? 1 : 0;
-    priv = ( req->pid_valid && req->priv_req ) ? S_MODE : U_MODE;
+    // Extract read/write/exec/priv attributes from request
+    get_attribs_from_req(req, &is_read, &is_write, &is_exec, &priv);
 
     // The process to translate an `IOVA` is as follows:
     // 1. If `ddtp.iommu_mode == Off` then stop and report "All inbound transactions

iommu_ref_model/test/tbapi.c

@@ -62,3 +62,36 @@ send_msg_iommu_to_hb(
     memcpy(&rcvd_msg, msg, sizeof(ats_msg_t));
     return;
 }
+
+void 
+get_attribs_from_req(
+    hb_to_iommu_req_t *req, uint8_t *read, uint8_t *write, uint8_t *exec, uint8_t *priv) {
+
+    *read = ( req->tr.read_writeAMO == READ ) ? 1 : 0;
+    *write = ( req->tr.read_writeAMO == WRITE ) ?  1 : 0;
+
+    // The No Write flag, when Set, indicates that the Function is requesting read-only 
+    // access for this translation.
+    // The TA (IOMMU) may ignore the No Write Flag, however, if the TA responds with a 
+    // translation marked as read-only then the Function must not issue Memory Write 
+    // transactions using that translation. In this case, the Function may issue another
+    // translation request with the No Write flag Clear, which may result in a new 
+    // translation completion with or without the W (Write) bit Set.
+    // Upon receiving a Translation Request with the NW flag Clear, TAs are permitted to
+    // mark the associated pages dirty. Functions MUST not issue such Requests 
+    // unless they have been given explicit write permission.
+    // Note ATS Translation requests are read - so read_writeAMO is READ for these requests
+    *write = ( (req->tr.at == ADDR_TYPE_PCIE_ATS_TRANSLATION_REQUEST) && 
+                 (req->no_write == 0) ) ? 1 : *write; 
+
+    // If a Translation Request has a PASID, the Untranslated Address Field is an address 
+    // within the process address space indicated by the PASID field.
+    // If a Translation Request has a PASID with either the Privileged Mode Requested 
+    // or Execute Requested bit Set, these may be used in constructing the Translation 
+    // Completion Data Entry.  The PASID Extended Capability indicates whether a Function
+    // supports and is enabled to send and receive TLPs with the PASID.
+    *exec = ( (*read && req->exec_req &&
+                (req->tr.at == ADDR_TYPE_UNTRANSLATED || req->pid_valid)) ) ? 1 : 0;
+    *priv = ( req->pid_valid && req->priv_req ) ? S_MODE : U_MODE;
+    return;
+}