[Update] Add improved error message for buffer allocation failure in HE-MEM (#3102)

* Add message notifying user of buffer allocation failure

* Fix mistake in catch blocks

* Fix caught exceptions not being references

* Fix typo

* Move SRC try-catch to only include the allocate call

* Throw exception after outputting message to user

* Remove unnecessary copies when rethrowing

Author: a-thompson2

samples/host_exerciser/host_exerciser_cmd.h

@@ -825,26 +825,44 @@ class host_exerciser_cmd : public test_command
 
         /* Allocate Source Buffer
         Write to CSR_SRC_ADDR */
-        std::cout << "Allocate SRC Buffer" << std::endl;
-        source_ = d_afu->allocate(LPBK1_BUFFER_ALLOCATION_SIZE);
+        try { 
+            std::cout << "Allocate SRC Buffer" << std::endl;
+            source_ = d_afu->allocate(LPBK1_BUFFER_ALLOCATION_SIZE);
+        }
+        catch (opae::fpga::types::except &ex) {
+            std::cerr << "SRC Buffer allocation failed. Please check that hugepages are reserved." << std::endl;
+            throw;
+        }
         host_exe_->logger_->debug("    VA 0x{0}  IOVA 0x{1:x}",
                                   (void*)source_->c_type(), source_->io_address());
         d_afu->write64(HE_SRC_ADDR, cacheline_aligned_addr(source_->io_address()));
         he_init_src_buffer(source_);
 
         /* Allocate Destination Buffer
             Write to CSR_DST_ADDR */
-        std::cout << "Allocate DST Buffer" << std::endl;
-        destination_ = d_afu->allocate(LPBK1_BUFFER_ALLOCATION_SIZE);
+        try {
+            std::cout << "Allocate DST Buffer" << std::endl;
+            destination_ = d_afu->allocate(LPBK1_BUFFER_ALLOCATION_SIZE);
+        }
+        catch (fpga::except &ex) {
+            std::cerr << "DST Buffer allocation failed. Please check that hugepages are reserved." << std::endl;
+            throw;
+        }
         host_exe_->logger_->debug("    VA 0x{0}  IOVA 0x{1:x}",
                                   (void*)destination_->c_type(), destination_->io_address());
         d_afu->write64(HE_DST_ADDR, cacheline_aligned_addr(destination_->io_address()));
         std::fill_n(destination_->c_type(), LPBK1_BUFFER_SIZE, 0xBE);
 
         /* Allocate DSM Buffer
             Write to CSR_AFU_DSM_BASEL */
-        std::cout << "Allocate DSM Buffer" << std::endl;
-        dsm_ = d_afu->allocate(LPBK1_DSM_SIZE);
+        try {
+            std::cout << "Allocate DSM Buffer" << std::endl;
+            dsm_ = d_afu->allocate(LPBK1_DSM_SIZE);
+        }
+        catch (fpga::except &ex) {
+            std::cerr << "DSM Buffer allocation failed. Please check that hugepages are reserved." << std::endl;
+            throw;
+        }
         host_exe_->logger_->debug("    VA 0x{0}  IOVA 0x{1:x}",
                                   (void*)dsm_->c_type(), dsm_->io_address());
         d_afu->write32(HE_DSM_BASEL, cacheline_aligned_addr(dsm_->io_address()));