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authorAndreas Sandberg <andreas.sandberg@arm.com>2017-07-27 09:24:22 +0000
committerAndreas Sandberg <andreas.sandberg@arm.com>2017-08-01 16:20:24 +0000
commit1935cec529ac2ae7d9b31f1e55f333a0769184b5 (patch)
tree2f2c1db4b255a802cf519ba11b7492f9a280c393 /src
parent9d6d3e5f7dd50e882a503ee4bb2ac7d9b8d21e30 (diff)
downloadgem5-1935cec529ac2ae7d9b31f1e55f333a0769184b5.tar.xz
kvm: Add a helper method to access device event queues
The VM's event queue is normally used for devices in multi-core KVM mode. Add a helper method, BaseKvmCPU::deviceEventQueue(), to access this queue. This makes the intention of code migrating to device event queues clearer. Change-Id: Ifb10f553a6d7445c8d562f658cf9d0b1f4c577ff Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com> Reviewed-on: https://gem5-review.googlesource.com/4287 Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Diffstat (limited to 'src')
-rw-r--r--src/cpu/kvm/base.cc7
-rw-r--r--src/cpu/kvm/base.hh10
-rw-r--r--src/cpu/kvm/x86_cpu.cc7
3 files changed, 16 insertions, 8 deletions
diff --git a/src/cpu/kvm/base.cc b/src/cpu/kvm/base.cc
index 6ea99ce4a..d0f7515de 100644
--- a/src/cpu/kvm/base.cc
+++ b/src/cpu/kvm/base.cc
@@ -1147,10 +1147,9 @@ BaseKvmCPU::doMMIOAccess(Addr paddr, void *data, int size, bool write)
delete pkt;
return clockPeriod() * ipr_delay;
} else {
- // Temporarily lock and migrate to the event queue of the
- // VM. This queue is assumed to "own" all devices we need to
- // access if running in multi-core mode.
- EventQueue::ScopedMigration migrate(vm.eventQueue());
+ // Temporarily lock and migrate to the device event queue to
+ // prevent races in multi-core mode.
+ EventQueue::ScopedMigration migrate(deviceEventQueue());
return dataPort.submitIO(pkt);
}
diff --git a/src/cpu/kvm/base.hh b/src/cpu/kvm/base.hh
index 29872e744..a22637f98 100644
--- a/src/cpu/kvm/base.hh
+++ b/src/cpu/kvm/base.hh
@@ -419,6 +419,16 @@ class BaseKvmCPU : public BaseCPU
void syncThreadContext();
/**
+ * Get a pointer to the event queue owning devices.
+ *
+ * Devices always live in a separate device event queue when
+ * running in multi-core mode. We need to temporarily migrate to
+ * this queue when accessing devices. By convention, devices and
+ * the VM use the same event queue.
+ */
+ EventQueue *deviceEventQueue() { return vm.eventQueue(); }
+
+ /**
* Update the KVM if the thread context is dirty.
*/
void syncKvmState();
diff --git a/src/cpu/kvm/x86_cpu.cc b/src/cpu/kvm/x86_cpu.cc
index bdbdadf71..467e1baaf 100644
--- a/src/cpu/kvm/x86_cpu.cc
+++ b/src/cpu/kvm/x86_cpu.cc
@@ -1346,10 +1346,9 @@ X86KvmCPU::handleKvmExitIO()
}
const MemCmd cmd(isWrite ? MemCmd::WriteReq : MemCmd::ReadReq);
- // Temporarily lock and migrate to the event queue of the
- // VM. This queue is assumed to "own" all devices we need to
- // access if running in multi-core mode.
- EventQueue::ScopedMigration migrate(vm.eventQueue());
+ // Temporarily lock and migrate to the device event queue to
+ // prevent races in multi-core mode.
+ EventQueue::ScopedMigration migrate(deviceEventQueue());
for (int i = 0; i < count; ++i) {
RequestPtr io_req = new Request(pAddr, kvm_run.io.size,
Request::UNCACHEABLE, dataMasterId());