Rob Donnelly

Thanks @Justin Refice.

Packing more than 4KB with uvm_packer results in a silent buffer overflow. This then causes silent data corruption on unpack. This issue is present in both UVM 1.2 and UVM 1800.2 2020. The attached test case was run on Questa 2020.4_2. UVM 1800.2-2020 1.1 Commands: gcc -m64 -fPIC -DQUESTA -g -W -shared -x c -I${QUESTA_ROOT}/include ${UVM_HOME}/src/dpi/uvm_dpi.cc -o uvm_dpi.so qrun -sv +incdir+${UVM_HOME}/src +define+UVM_1800_2_2020 -sv_lib uvm_dpi ${UVM_HOME}/src/uvm_pkg.sv uvm_packer_buffer_overflow.sv Errors: # UVM_ERROR uvm_packer_buffer_overflow.sv(49) @ 0: reporter [uvm_packer_buffer_overflow] data_out[1024]:0x00000000 != data_in[1022]:0x9b387ab5 # UVM_ERROR uvm_packer_buffer_overflow.sv(49) @ 0: reporter [uvm_packer_buffer_overflow] data_out[1025]:0x00000000 != data_in[1023]:0x5d3822c4 # UVM_ERROR uvm_packer_buffer_overflow.sv(49) @ 0: reporter [uvm_packer_buffer_overflow] data_out[1026]:0x00000000 != data_in[1024]:0xc6462f4a UVM 1.2 Command: qrun -sv +define+UVM_1_2 uvm_packer_buffer_overflow.sv Error: # UVM_ERROR uvm_packer_buffer_overflow.sv(49) @ 0: reporter [uvm_packer_buffer_overflow] data_out[1024]:0x00000000 != data_in[1024]:0xc6462f4a Test program uvm_packer_buffer_overflow; import uvm_pkg::*; `include "uvm_macros.svh" initial begin int uvm_packer_max_bytes = 4096; int uvm_packer_max_dwords = uvm_packer_max_bytes / 4; int unsigned data_in[] = new[uvm_packer_max_dwords + 1]; int unsigned data_out[]; int offset; uvm_packer p = new(); foreach (data_in[i]) begin data_in[i] = $urandom(); end foreach (data_in[i]) begin p.pack_field_int(data_in[i], $size(data_in[i])); end `ifdef UVM_1_2 p.set_packed_size(); p.get_ints(data_out); `endif `ifdef UVM_1800_2_2020 p.get_packed_ints(data_out); // 1800.2 2020 prepends m_pack_iter and m_unpack_iter offset = 2; `endif assert (data_out.size() == (data_in.size() + offset)) else begin `uvm_error("uvm_packer_buffer_overflow", $sformatf( "data_out.size:%0d != (data_in.size:%0d + offset:%0d):%0d", data_out.size(), data_in.size(), offset, data_in.size() + offset )) end foreach (data_out[i]) begin // Don't compare the following entries for UVM 1800.2 2020: // data_out[0]: m_pack_iter // data_out[1]: m_unpack_iter if (i < offset) continue; if (data_out[i] != data_in[i - offset]) begin `uvm_error("uvm_packer_buffer_overflow", $sformatf( "data_out[%0d]:0x%x != data_in[%0d]:0x%x", i, data_out[i], i - offset, data_in[i - offset] )) end end end endprogram uvm_packer_buffer_overflow.sv