From 4d2b7035d945b0921657293afa7fe84ba6f9c91f Mon Sep 17 00:00:00 2001
From: ParantezTech <12572227+par274@users.noreply.github.com>
Date: Tue, 6 Oct 2026 13:44:48 +0300
Subject: [PATCH] [Kernel] Poll host semaphore waits and deliver guest
 exceptions

Co-authored-by: Sekai <140012992+igettingit@users.noreply.github.com>
---
 .../Kernel/KernelSemaphoreCompatExports.cs    | 55 ++++++++++++-------
 1 file changed, 35 insertions(+), 20 deletions(-)

diff --git a/src/SharpEmu.Libs/Kernel/KernelSemaphoreCompatExports.cs b/src/SharpEmu.Libs/Kernel/KernelSemaphoreCompatExports.cs
index afc2bb7..584a057 100644
--- a/src/SharpEmu.Libs/Kernel/KernelSemaphoreCompatExports.cs
+++ b/src/SharpEmu.Libs/Kernel/KernelSemaphoreCompatExports.cs
@@ -266,40 +266,55 @@ public static class KernelSemaphoreCompatExports
         var deadlineMs = hasTimeout
             ? Environment.TickCount64 + Math.Max(1L, timeoutUsec / 1000L)
             : long.MaxValue;
-        lock (semaphore.Gate)
+        if (_traceSema)
         {
-            if (_traceSema)
+            lock (semaphore.Gate)
             {
                 TraceSemaphore(
                     $"wait-host-block handle=0x{handle:X8} name='{semaphore.Name}' need={needCount} " +
-                    $"count={semaphore.Count} timeout={(timeoutAddress == 0 ? "infinite" : timeoutUsec)} {FormatCallSite(ctx)}");
+                    $"count={semaphore.Count} timeout={(hasTimeout ? timeoutUsec : "infinite")} {FormatCallSite(ctx)}");
             }
-            while (semaphore.Count < needCount)
+        }
+
+        while (true)
+        {
+            lock (semaphore.Gate)
             {
+                if (semaphore.Count >= needCount)
+                {
+                    semaphore.Count -= needCount;
+                    semaphore.WaitingThreads = Math.Max(0, semaphore.WaitingThreads - 1);
+                    if (_traceSema)
+                    {
+                        TraceSemaphore(
+                            $"wait-host-wake handle=0x{handle:X8} name='{semaphore.Name}' need={needCount} count={semaphore.Count} {FormatCallSite(ctx)}");
+                    }
+                    if (timeoutAddress != 0)
+                    {
+                        _ = TryWriteUInt32(ctx, timeoutAddress, 0);
+                    }
+
+                    return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_OK);
+                }
+
                 var remaining = deadlineMs - Environment.TickCount64;
-                if (timeoutAddress != 0 && remaining <= 0)
+                if (hasTimeout && remaining <= 0)
                 {
                     semaphore.WaitingThreads = Math.Max(0, semaphore.WaitingThreads - 1);
-                    _ = TryWriteUInt32(ctx, timeoutAddress, 0);
+                    if (timeoutAddress != 0)
+                    {
+                        _ = TryWriteUInt32(ctx, timeoutAddress, 0);
+                    }
                     return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_ERROR_TIMED_OUT);
                 }
 
-                Monitor.Wait(semaphore.Gate, (int)Math.Min(remaining, 100));
+                var waitMilliseconds = hasTimeout
+                    ? (int)Math.Max(1L, Math.Min(remaining, 10L))
+                    : 10;
+                Monitor.Wait(semaphore.Gate, waitMilliseconds);
             }
 
-            semaphore.Count -= needCount;
-            semaphore.WaitingThreads = Math.Max(0, semaphore.WaitingThreads - 1);
-            if (_traceSema)
-            {
-                TraceSemaphore(
-                    $"wait-host-wake handle=0x{handle:X8} name='{semaphore.Name}' need={needCount} count={semaphore.Count} {FormatCallSite(ctx)}");
-            }
-            if (timeoutAddress != 0)
-            {
-                _ = TryWriteUInt32(ctx, timeoutAddress, 0);
-            }
-
-            return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_OK);
+            GuestThreadExecution.Scheduler?.DeliverPendingGuestExceptionIfReady(ctx);
         }
     }