From 615fb40416b9ee10abf40a036b31d1540886a9b8 Mon Sep 17 00:00:00 2001
From: bunnei <bunneidev@gmail.com>
Date: Fri, 21 Jan 2022 17:10:11 -0800
Subject: [PATCH] hle: kernel: KThread: Ensure host (dummy) threads block on
locking.
- But do not enter the priority queue, as otherwise they will be scheduled.
- Allows dummy threads to use guest synchronization primitives.
---
src/core/hle/kernel/k_priority_queue.h | 36 +++++++++++++++++++++++++
src/core/hle/kernel/k_scheduler.cpp | 3 +++
src/core/hle/kernel/k_thread.cpp | 37 ++++++++++++++++++++++++++
src/core/hle/kernel/k_thread.h | 13 +++++++++
4 files changed, 89 insertions(+)
diff --git a/src/core/hle/kernel/k_priority_queue.h b/src/core/hle/kernel/k_priority_queue.h
index f4d71ad7e..0b894c8cf 100644
--- a/src/core/hle/kernel/k_priority_queue.h
+++ b/src/core/hle/kernel/k_priority_queue.h
@@ -45,6 +45,7 @@ concept KPriorityQueueMember = !std::is_reference_v<T> && requires(T & t) {
{ t.GetActiveCore() } -> Common::ConvertibleTo<s32>;
{ t.GetPriority() } -> Common::ConvertibleTo<s32>;
+ { t.IsDummyThread() } -> Common::ConvertibleTo<bool>;
};
template <typename Member, size_t NumCores_, int LowestPriority, int HighestPriority>
@@ -349,24 +350,49 @@ public:
// Mutators.
constexpr void PushBack(Member* member) {
+ // This is for host (dummy) threads that we do not want to enter the priority queue.
+ if (member->IsDummyThread()) {
+ return;
+ }
+
this->PushBack(member->GetPriority(), member);
}
constexpr void Remove(Member* member) {
+ // This is for host (dummy) threads that we do not want to enter the priority queue.
+ if (member->IsDummyThread()) {
+ return;
+ }
+
this->Remove(member->GetPriority(), member);
}
constexpr void MoveToScheduledFront(Member* member) {
+ // This is for host (dummy) threads that we do not want to enter the priority queue.
+ if (member->IsDummyThread()) {
+ return;
+ }
+
this->scheduled_queue.MoveToFront(member->GetPriority(), member->GetActiveCore(), member);
}
constexpr KThread* MoveToScheduledBack(Member* member) {
+ // This is for host (dummy) threads that we do not want to enter the priority queue.
+ if (member->IsDummyThread()) {
+ return {};
+ }
+
return this->scheduled_queue.MoveToBack(member->GetPriority(), member->GetActiveCore(),
member);
}
// First class fancy operations.
constexpr void ChangePriority(s32 prev_priority, bool is_running, Member* member) {
+ // This is for host (dummy) threads that we do not want to enter the priority queue.
+ if (member->IsDummyThread()) {
+ return;
+ }
+
ASSERT(IsValidPriority(prev_priority));
// Remove the member from the queues.
@@ -383,6 +409,11 @@ public:
constexpr void ChangeAffinityMask(s32 prev_core, const AffinityMaskType& prev_affinity,
Member* member) {
+ // This is for host (dummy) threads that we do not want to enter the priority queue.
+ if (member->IsDummyThread()) {
+ return;
+ }
+
// Get the new information.
const s32 priority = member->GetPriority();
const AffinityMaskType& new_affinity = member->GetAffinityMask();
@@ -412,6 +443,11 @@ public:
}
constexpr void ChangeCore(s32 prev_core, Member* member, bool to_front = false) {
+ // This is for host (dummy) threads that we do not want to enter the priority queue.
+ if (member->IsDummyThread()) {
+ return;
+ }
+
// Get the new information.
const s32 new_core = member->GetActiveCore();
const s32 priority = member->GetPriority();
diff --git a/src/core/hle/kernel/k_scheduler.cpp b/src/core/hle/kernel/k_scheduler.cpp
index 1b2a01869..b32d4f285 100644
--- a/src/core/hle/kernel/k_scheduler.cpp
+++ b/src/core/hle/kernel/k_scheduler.cpp
@@ -406,6 +406,9 @@ void KScheduler::EnableScheduling(KernelCore& kernel, u64 cores_needing_scheduli
} else {
RescheduleCores(kernel, cores_needing_scheduling);
}
+
+ // Special case to ensure dummy threads that are waiting block.
+ current_thread->IfDummyThreadTryWait();
}
u64 KScheduler::UpdateHighestPriorityThreads(KernelCore& kernel) {
diff --git a/src/core/hle/kernel/k_thread.cpp b/src/core/hle/kernel/k_thread.cpp
index 4cbf12c11..f42abb8a1 100644
--- a/src/core/hle/kernel/k_thread.cpp
+++ b/src/core/hle/kernel/k_thread.cpp
@@ -1075,12 +1075,46 @@ ResultCode KThread::Sleep(s64 timeout) {
return ResultSuccess;
}
+void KThread::IfDummyThreadTryWait() {
+ if (!IsDummyThread()) {
+ return;
+ }
+
+ if (GetState() != ThreadState::Waiting) {
+ return;
+ }
+
+ // Block until we can grab the lock.
+ KScopedSpinLock lk{dummy_wait_lock};
+}
+
+void KThread::IfDummyThreadBeginWait() {
+ if (!IsDummyThread()) {
+ return;
+ }
+
+ // Ensure the thread will block when IfDummyThreadTryWait is called.
+ dummy_wait_lock.Lock();
+}
+
+void KThread::IfDummyThreadEndWait() {
+ if (!IsDummyThread()) {
+ return;
+ }
+
+ // Ensure the thread will no longer block.
+ dummy_wait_lock.Unlock();
+}
+
void KThread::BeginWait(KThreadQueue* queue) {
// Set our state as waiting.
SetState(ThreadState::Waiting);
// Set our wait queue.
wait_queue = queue;
+
+ // Special case for dummy threads to ensure they block.
+ IfDummyThreadBeginWait();
}
void KThread::NotifyAvailable(KSynchronizationObject* signaled_object, ResultCode wait_result_) {
@@ -1106,6 +1140,9 @@ void KThread::EndWait(ResultCode wait_result_) {
}
wait_queue->EndWait(this, wait_result_);
+
+ // Special case for dummy threads to wakeup if necessary.
+ IfDummyThreadEndWait();
}
}
diff --git a/src/core/hle/kernel/k_thread.h b/src/core/hle/kernel/k_thread.h
index 77b53a198..d058db62c 100644
--- a/src/core/hle/kernel/k_thread.h
+++ b/src/core/hle/kernel/k_thread.h
@@ -558,6 +558,10 @@ public:
return thread_type;
}
+ [[nodiscard]] bool IsDummyThread() const {
+ return GetThreadType() == ThreadType::Dummy;
+ }
+
void SetWaitObjectsForDebugging(const std::span<KSynchronizationObject*>& objects) {
wait_objects_for_debugging.clear();
wait_objects_for_debugging.reserve(objects.size());
@@ -632,6 +636,14 @@ public:
return condvar_key;
}
+ // Dummy threads (used for HLE host threads) cannot wait based on the guest scheduler, and
+ // therefore will not block on guest kernel synchronization primitives. These methods handle
+ // blocking as needed.
+
+ void IfDummyThreadTryWait();
+ void IfDummyThreadBeginWait();
+ void IfDummyThreadEndWait();
+
private:
static constexpr size_t PriorityInheritanceCountMax = 10;
union SyncObjectBuffer {
@@ -750,6 +762,7 @@ private:
bool resource_limit_release_hint{};
StackParameters stack_parameters{};
KSpinLock context_guard{};
+ KSpinLock dummy_wait_lock{};
// For emulation
std::shared_ptr<Common::Fiber> host_context{};