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>

12 files changed, 52 insertions, 11 deletions

diff --git a/configs/example/fs.py b/configs/example/fs.py
index 1ada59084..8102edc75 100644
--- a/configs/example/fs.py
+++ b/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)
diff --git a/configs/example/se.py b/configs/example/se.py
index c48b99eb4..4adfe7bb8 100644
--- a/configs/example/se.py
+++ b/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
diff --git a/src/arch/arm/kvm/KvmGic.py b/src/arch/arm/kvm/KvmGic.py
index 74bfe1e0b..9ae52db22 100644
--- a/src/arch/arm/kvm/KvmGic.py
+++ b/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)')
diff --git a/src/arch/arm/kvm/gic.cc b/src/arch/arm/kvm/gic.cc
index 684f026f0..c5a30879c 100644
--- a/src/arch/arm/kvm/gic.cc
+++ b/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}
 {
 }
diff --git a/src/cpu/kvm/BaseKvmCPU.py b/src/cpu/kvm/BaseKvmCPU.py
index 4c64f24ed..cc0b28fe9 100644
--- a/src/cpu/kvm/BaseKvmCPU.py
+++ b/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,
diff --git a/src/cpu/kvm/KvmVM.py b/src/cpu/kvm/KvmVM.py
index 478a91682..cbc92ca0d 100644
--- a/src/cpu/kvm/KvmVM.py
+++ b/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")
diff --git a/src/cpu/kvm/base.cc b/src/cpu/kvm/base.cc
index 723feda44..6ae3c7dff 100644
--- a/src/cpu/kvm/base.cc
+++ b/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),
diff --git a/src/cpu/kvm/vm.cc b/src/cpu/kvm/vm.cc
index d3ab8c45a..604d182ab 100644
--- a/src/cpu/kvm/vm.cc
+++ b/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)
 {
diff --git a/src/cpu/kvm/vm.hh b/src/cpu/kvm/vm.hh
index 560efb606..dbd46aa3c 100644
--- a/src/cpu/kvm/vm.hh
+++ b/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
     /**
diff --git a/src/sim/System.py b/src/sim/System.py
index 34b1fd127..e3e42d862 100644
--- a/src/sim/System.py
+++ b/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)')
diff --git a/src/sim/system.cc b/src/sim/system.cc
index 09be232a7..9315882b7 100644
--- a/src/sim/system.cc
+++ b/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)
diff --git a/src/sim/system.hh b/src/sim/system.hh
index 1bbd37d9d..c3667fe09 100644
--- a/src/sim/system.hh
+++ b/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;