sim, kvm: make KvmVM a System parameter

A KVM VM is typically a child of the System object already, but for
solving future issues with configuration graph resolution, the most
logical way to keep track of this object is for it to be an actual
parameter of the System object.

Change-Id: I965ded22203ff8667db9ca02de0042ff1c772220
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

configs/example/fs.py

@@ -143,7 +143,7 @@ def build_test_system(np):
                     for i in xrange(np)]
 
     if is_kvm_cpu(TestCPUClass) or is_kvm_cpu(FutureClass):
-        test_sys.vm = KvmVM()
+        test_sys.kvm_vm = KvmVM()
 
     if options.ruby:
         # Check for timing mode because ruby does not support atomic accesses
@@ -280,7 +280,7 @@ def build_drive_system(np):
         drive_sys.kernel = binary(options.kernel)
 
     if is_kvm_cpu(DriveCPUClass):
-        drive_sys.vm = KvmVM()
+        drive_sys.kvm_vm = KvmVM()
 
     drive_sys.iobridge = Bridge(delay='50ns',
                                 ranges = drive_sys.mem_ranges)

configs/example/se.py

@@ -209,7 +209,7 @@ for cpu in system.cpu:
 
 if is_kvm_cpu(CPUClass) or is_kvm_cpu(FutureClass):
     if buildEnv['TARGET_ISA'] == 'x86':
-        system.vm = KvmVM()
+        system.kvm_vm = KvmVM()
         for process in multiprocesses:
             process.useArchPT = True
             process.kvmInSE = True

src/arch/arm/kvm/KvmGic.py

@@ -52,4 +52,3 @@ class KvmGic(BaseGic):
 
     system = Param.System(Parent.any,
                           'System this interrupt controller belongs to')
-    kvmVM = Param.KvmVM(Parent.any, 'KVM VM (i.e., shared memory domain)')

src/arch/arm/kvm/gic.cc

@@ -106,7 +106,8 @@ KvmKernelGicV2::setIntState(unsigned type, unsigned vcpu, unsigned irq,
 KvmGic::KvmGic(const KvmGicParams *p)
     : BaseGic(p),
       system(*p->system),
-      kernelGic(*p->kvmVM, p->cpu_addr, p->dist_addr, p->it_lines),
+      kernelGic(*system.getKvmVM(),
+                p->cpu_addr, p->dist_addr, p->it_lines),
       addrRanges{kernelGic.distRange, kernelGic.cpuRange}
 {
 }

src/cpu/kvm/BaseKvmCPU.py

@@ -64,7 +64,6 @@ class BaseKvmCPU(BaseCPU):
     def support_take_over(cls):
         return True
 
-    kvmVM = Param.KvmVM(Parent.any, 'KVM VM (i.e., shared memory domain)')
     useCoalescedMMIO = Param.Bool(False, "Use coalesced MMIO (EXPERIMENTAL)")
     usePerfOverflow = Param.Bool(False, "Use perf event overflow counters (EXPERIMENTAL)")
     alwaysSyncTC = Param.Bool(False,

src/cpu/kvm/KvmVM.py

@@ -44,6 +44,5 @@ class KvmVM(SimObject):
     type = 'KvmVM'
     cxx_header = "cpu/kvm/vm.hh"
 
-    system = Param.System(Parent.any, "system object")
-
-    coalescedMMIO = VectorParam.AddrRange([], "memory ranges for coalesced MMIO")
+    coalescedMMIO = \
+      VectorParam.AddrRange([], "memory ranges for coalesced MMIO")

src/cpu/kvm/base.cc

@@ -64,7 +64,7 @@
 
 BaseKvmCPU::BaseKvmCPU(BaseKvmCPUParams *params)
     : BaseCPU(params),
-      vm(*params->kvmVM),
+      vm(*params->system->getKvmVM()),
       _status(Idle),
       dataPort(name() + ".dcache_port", this),
       instPort(name() + ".icache_port", this),

src/cpu/kvm/vm.cc

@@ -292,7 +292,7 @@ Kvm::createVM()
 
 KvmVM::KvmVM(KvmVMParams *params)
     : SimObject(params),
-      kvm(new Kvm()), system(params->system),
+      kvm(new Kvm()), system(nullptr),
       vmFD(kvm->createVM()),
       started(false),
       nextVCPUID(0)
@@ -342,6 +342,7 @@ KvmVM::cpuStartup()
 void
 KvmVM::delayedStartup()
 {
+    assert(system); // set by the system during its construction
     const std::vector<BackingStoreEntry> &memories(
         system->getPhysMem().getBackingStore());
 
@@ -526,6 +527,13 @@ KvmVM::createDevice(uint32_t type, uint32_t flags)
 #endif
 }
 
+void
+KvmVM::setSystem(System *s) {
+    panic_if(system != nullptr, "setSystem() can only be called once");
+    panic_if(s == nullptr, "setSystem() called with null System*");
+    system = s;
+}
+
 int
 KvmVM::createVCPU(long vcpuID)
 {

src/cpu/kvm/vm.hh

@@ -400,6 +400,11 @@ class KvmVM : public SimObject
     /** Global KVM interface */
     Kvm *kvm;
 
+    /**
+     * Initialize system pointer. Invoked by system object.
+     */
+    void setSystem(System *s);
+
 #if defined(__aarch64__)
   public: // ARM-specific
     /**

src/sim/System.py

@@ -29,6 +29,7 @@
 #          Rick Strong
 
 from m5.SimObject import SimObject
+from m5.defines import buildEnv
 from m5.params import *
 from m5.proxy import *
 
@@ -106,3 +107,6 @@ class System(MemObject):
     # Dynamic voltage and frequency handler for the system, disabled by default
     # Provide list of domains that need to be controlled by the handler
     dvfs_handler = DVFSHandler()
+
+    if buildEnv['USE_KVM']:
+        kvm_vm = Param.KvmVM(NULL, 'KVM VM (i.e., shared memory domain)')

src/sim/system.cc

@@ -53,6 +53,10 @@
 #include "base/loader/symtab.hh"
 #include "base/str.hh"
 #include "base/trace.hh"
+#include "config/use_kvm.hh"
+#if USE_KVM
+#include "cpu/kvm/vm.hh"
+#endif
 #include "cpu/thread_context.hh"
 #include "debug/Loader.hh"
 #include "debug/WorkItems.hh"
@@ -90,6 +94,11 @@ System::System(Params *p)
       kernel(nullptr),
       loadAddrMask(p->load_addr_mask),
       loadAddrOffset(p->load_offset),
+#if USE_KVM
+      kvmVM(p->kvm_vm),
+#else
+      kvmVM(nullptr),
+#endif
       physmem(name() + ".physmem", p->memories, p->mmap_using_noreserve),
       memoryMode(p->mem_mode),
       _cacheLineSize(p->cache_line_size),
@@ -104,6 +113,12 @@ System::System(Params *p)
     // add self to global system list
     systemList.push_back(this);
 
+#if USE_KVM
+    if (kvmVM) {
+        kvmVM->setSystem(this);
+    }
+#endif
+
     if (FullSystem) {
         kernelSymtab = new SymbolTable;
         if (!debugSymbolTable)

src/sim/system.hh

@@ -72,6 +72,7 @@
 
 class BaseRemoteGDB;
 class GDBListener;
+class KvmVM;
 class ObjectFile;
 class ThreadContext;
 
@@ -249,6 +250,14 @@ class System : public MemObject
     Addr loadAddrOffset;
 
   public:
+    /**
+     * Get a pointer to the Kernel Virtual Machine (KVM) SimObject,
+     * if present.
+     */
+    KvmVM* getKvmVM() {
+        return kvmVM;
+    }
+
     /** Get a pointer to access the physical memory of the system */
     PhysicalMemory& getPhysMem() { return physmem; }
 
@@ -289,6 +298,8 @@ class System : public MemObject
 
   protected:
 
+    KvmVM *const kvmVM;
+
     PhysicalMemory physmem;
 
     Enums::MemoryMode memoryMode;