gpu-compute: Don't use emulated driver in full system

The emulated driver is currently called in a few locations
unconditionally. This changeset adds checks that we are not in full
system before calling any emulated driver function. In full system the
amdgpu driver running on the disk image handles these functions.

Change-Id: Iea3546b574e29c649351c0fce9154530be89e9b1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57712
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/gpu-compute/compute_unit.cc

@@ -1051,13 +1051,18 @@ ComputeUnit::sendRequest(GPUDynInstPtr gpuDynInst, PortID index, PacketPtr pkt)
     // only do some things if actually accessing data
     bool isDataAccess = pkt->isWrite() || pkt->isRead();
 
-    // For dGPUs, real hardware will extract MTYPE from the PTE.  Our model
+    // For dGPUs, real hardware will extract MTYPE from the PTE. SE mode
     // uses x86 pagetables which don't have fields to track GPU MTYPEs.
     // Rather than hacking up the pagetable to add these bits in, we just
     // keep a structure local to our GPUs that are populated in our
     // emulated driver whenever memory is allocated.  Consult that structure
     // here in case we need a memtype override.
-    shader->gpuCmdProc.driver()->setMtype(pkt->req);
+    //
+    // In full system mode these can be extracted from the PTE and assigned
+    // after address translation takes place.
+    if (!FullSystem) {
+        shader->gpuCmdProc.driver()->setMtype(pkt->req);
+    }
 
     // Check write before read for atomic operations
     // since atomic operations should use BaseMMU::Write
@@ -1075,7 +1080,7 @@ ComputeUnit::sendRequest(GPUDynInstPtr gpuDynInst, PortID index, PacketPtr pkt)
     PortID tlbPort_index = perLaneTLB ? index : 0;
 
     if (shader->timingSim) {
-        if (debugSegFault) {
+        if (!FullSystem && debugSegFault) {
             Process *p = shader->gpuTc->getProcessPtr();
             Addr vaddr = pkt->req->getVaddr();
             unsigned size = pkt->getSize();

src/gpu-compute/gpu_compute_driver.cc

@@ -1023,6 +1023,7 @@ GPUComputeDriver::setMtype(RequestPtr req)
 {
     // If we are a dGPU then set the MTYPE from our VMAs.
     if (isdGPU) {
+        assert(!FullSystem);
         AddrRange range = RangeSize(req->getVaddr(), req->getSize());
         auto vma = gpuVmas.contains(range);
         assert(vma != gpuVmas.end());