[loader] cut import overhead (#32)

src/SharpEmu.Core/Cpu/Native/DirectExecutionBackend.Imports.cs

@@ -633,25 +633,56 @@ public sealed partial class DirectExecutionBackend
 			"ASoW5WE-UPo" or // sceKernelAprSubmitCommandBufferAndGetResult
 			"rqwFKI4PAiM" or // sceKernelAprWaitCommandBuffer
 			"eE4Szl8sil8" or // sceKernelAprSubmitCommandBuffer
-			"qvMUCyyaCSI";   // sceKernelAprSubmitCommandBufferAndGetId
+			"qvMUCyyaCSI" or // sceKernelAprSubmitCommandBufferAndGetId
+			"Q2V+iqvjgC0" or // vsnprintf
+			"q1cHNfGycLI" or // scePadRead
+			"xk0AcarP3V4" or // scePadOpen
+			"yH17Q6NWtVg" or // sceUserServiceGetEvent
+			"D-CzAxQL0XI" or // sceUserServiceGetPlatformPrivacySetting
+			"K-jXhbt2gn4";   // scePthreadMutexTrylock
 
 	private bool ShouldLogImportResult(string nid, OrbisGen2Result result)
 	{
+		var resultValue = unchecked((int)result);
+		if (resultValue > 0)
+		{
+			return false;
+		}
+
 		var expectedFileProbeMiss =
 			result == OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND &&
 			IsExpectedFileProbeNotFoundNid(nid);
 		var expectedTimedWaitTimeout =
 			string.Equals(nid, "27bAgiJmOh0", StringComparison.Ordinal) &&
 			unchecked((int)result) == 60;
+		var expectedEqueueTimeout =
+			string.Equals(nid, "fzyMKs9kim0", StringComparison.Ordinal) &&
+			result == OrbisGen2Result.ORBIS_GEN2_ERROR_TIMED_OUT;
 		var expectedMutexTrylockBusy =
 			string.Equals(nid, "K-jXhbt2gn4", StringComparison.Ordinal) &&
 			result == OrbisGen2Result.ORBIS_GEN2_ERROR_BUSY;
-		if (!expectedFileProbeMiss && !expectedTimedWaitTimeout && !expectedMutexTrylockBusy)
+		var expectedUserServiceNoEvent =
+			string.Equals(nid, "yH17Q6NWtVg", StringComparison.Ordinal) &&
+			resultValue == unchecked((int)0x80960007);
+		var expectedPrivacyInvalidParameter =
+			string.Equals(nid, "D-CzAxQL0XI", StringComparison.Ordinal) &&
+			resultValue == unchecked((int)0x80960009);
+		if (!expectedFileProbeMiss &&
+			!expectedTimedWaitTimeout &&
+			!expectedEqueueTimeout &&
+			!expectedMutexTrylockBusy &&
+			!expectedUserServiceNoEvent &&
+			!expectedPrivacyInvalidParameter)
 		{
 			return true;
 		}
 
-		var key = nid + "\0" + (int)result;
+		if (!ShouldLogExpectedImportResults())
+		{
+			return false;
+		}
+
+		var key = nid + "\0" + resultValue;
 		int count;
 		lock (_importResultLogSampleGate)
 		{
@@ -663,6 +694,12 @@ public sealed partial class DirectExecutionBackend
 		return count <= 8 || count % 10000 == 0;
 	}
 
+	private static bool ShouldLogExpectedImportResults() =>
+		string.Equals(
+			Environment.GetEnvironmentVariable("SHARPEMU_LOG_EXPECTED_IMPORT_RESULTS"),
+			"1",
+			StringComparison.Ordinal);
+
 	private static bool IsExpectedFileProbeNotFoundNid(string nid) =>
 		nid is
 			"eV9wAD2riIA" or // sceKernelStat

src/SharpEmu.Core/Memory/PhysicalVirtualMemory.cs

@@ -11,7 +11,9 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
 {
     private readonly ReaderWriterLockSlim _gate = new(LockRecursionPolicy.SupportsRecursion);
     private readonly object _guestAllocationGate = new();
+    private readonly object _allocationSearchHintGate = new();
     private readonly List<MemoryRegion> _regions = new();
+    private readonly Dictionary<(ulong DesiredAddress, ulong Alignment, bool Executable), ulong> _allocationSearchHints = new();
     private readonly Dictionary<ulong, ProgramHeaderFlags> _pageProtections = new();
     private bool _disposed;
     private const ulong PageSize = 0x1000;
@@ -19,7 +21,8 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
     private const ulong GuestAllocationArenaSize = 0x0100_0000;
     private const ulong GuestAllocationArenaStartOffset = PageSize;
     private const ulong LargeDataReserveThreshold = 0x4000_0000UL; // 1 GiB
-    private const ulong LazyReservePrimeBytes = 0x5000_0000UL; // 1.25 GiB
+    private const ulong FullCommitRegionLimit = 4UL << 30;
+    private const ulong DefaultLazyReservePrimeBytes = 0x0400_0000UL; // 64 MiB
     private const ulong LazyReservePrimeChunkBytes = 0x0200_0000UL; // 32 MiB
 
     private const uint MEM_COMMIT = 0x1000;
@@ -35,6 +38,7 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
 
     private ulong _guestAllocationArenaBase;
     private ulong _guestAllocationOffset;
+    private static readonly ulong LazyReservePrimeBytes = ResolveLazyReservePrimeBytes();
 
     [DllImport("kernel32.dll", SetLastError = true)]
     private static extern void* VirtualAlloc(void* lpAddress, nuint dwSize, uint flAllocationType, uint flProtect);
@@ -96,7 +100,7 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
         }
 
         var allocationKind = executable ? "executable memory" : "data memory";
-        Console.Error.WriteLine($"[VMEM] Allocated exact {allocationKind}: 0x{actualAddress:X16} - 0x{actualAddress + alignedSize:X16} ({alignedSize} bytes)");
+        TraceVmem($"Allocated exact {allocationKind}: 0x{actualAddress:X16} - 0x{actualAddress + alignedSize:X16} ({alignedSize} bytes)");
         return true;
     }
 
@@ -110,7 +114,9 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
         var protection = executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
         var allocationType = MEM_COMMIT | MEM_RESERVE;
         var reservedOnly = false;
-        var preferReserveOnly = !executable && alignedSize >= LargeDataReserveThreshold;
+        var preferReserveOnly = !executable &&
+            alignedSize >= LargeDataReserveThreshold &&
+            alignedSize > FullCommitRegionLimit;
 
         void* result = null;
         if (preferReserveOnly)
@@ -139,7 +145,7 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
                 throw new InvalidOperationException($"Failed to allocate exact mapping at 0x{desiredAddress:X16} ({alignedSize} bytes)");
             }
 
-            Console.Error.WriteLine($"[VMEM] Could not allocate at 0x{desiredAddress:X16}, trying any address...");
+            TraceVmem($"Could not allocate at 0x{desiredAddress:X16}, trying any address...");
             result = VirtualAlloc(null, (nuint)alignedSize, allocationType, protection);
 
             if (result == null)
@@ -193,12 +199,12 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
                     lazyPrimeState = committedBytes == primeBytes
                         ? $"ok:{committedBytes:X}"
                         : $"partial:{committedBytes:X}/{primeBytes:X}";
-                    Console.Error.WriteLine($"[VMEM] Primed lazy region: 0x{actualAddress:X16} - 0x{actualAddress + committedBytes:X16} ({committedBytes} bytes)");
+                    TraceVmem($"Primed lazy region: 0x{actualAddress:X16} - 0x{actualAddress + committedBytes:X16} ({committedBytes} bytes)");
                 }
                 else
                 {
                     lazyPrimeState = $"fail:{primeBytes:X}";
-                    Console.Error.WriteLine($"[VMEM] Failed to prime lazy region at 0x{actualAddress:X16} ({primeBytes} bytes), continuing with on-demand commit");
+                    TraceVmem($"Failed to prime lazy region at 0x{actualAddress:X16} ({primeBytes} bytes), continuing with on-demand commit");
                 }
             }
             else
@@ -227,7 +233,7 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
         var allocationKind = reservedOnly
             ? "reserved data memory (lazy commit)"
             : (executable ? "executable memory" : "data memory");
-        Console.Error.WriteLine($"[VMEM] Allocated {allocationKind}: 0x{actualAddress:X16} - 0x{actualAddress + alignedSize:X16} ({alignedSize} bytes) lazy_prime={lazyPrimeState}");
+        TraceVmem($"Allocated {allocationKind}: 0x{actualAddress:X16} - 0x{actualAddress + alignedSize:X16} ({alignedSize} bytes) lazy_prime={lazyPrimeState}");
 
         return actualAddress;
     }
@@ -247,7 +253,8 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
 
         var alignedSize = AlignUp(size, PageSize);
         var effectiveAlignment = Math.Max(PageSize, alignment == 0 ? PageSize : alignment);
-        var cursor = AlignUp(desiredAddress, effectiveAlignment);
+        var requestedCursor = AlignUp(desiredAddress, effectiveAlignment);
+        var cursor = GetAllocationSearchCursor(desiredAddress, requestedCursor, effectiveAlignment, executable);
 
         for (var attempt = 0; attempt < 0x10000; attempt++)
         {
@@ -267,6 +274,7 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
                 actualAddress = AllocateAt(cursor, alignedSize, executable, allowAlternative: false);
                 if (actualAddress == cursor)
                 {
+                    UpdateAllocationSearchCursor(desiredAddress, effectiveAlignment, executable, actualAddress + alignedSize);
                     return true;
                 }
 
@@ -334,6 +342,10 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
                 }
                 _regions.Clear();
                 _pageProtections.Clear();
+                lock (_allocationSearchHintGate)
+                {
+                    _allocationSearchHints.Clear();
+                }
             }
             finally
             {
@@ -390,7 +402,7 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
 
             ApplySegmentProtection(mapStart, mapEnd, protection);
 
-            Console.Error.WriteLine($"[VMEM] Mapped segment: 0x{virtualAddress:X16} - 0x{virtualAddress + memorySize:X16} (file: {fileData.Length} bytes, prot: {protection})");
+            TraceVmem($"Mapped segment: 0x{virtualAddress:X16} - 0x{virtualAddress + memorySize:X16} (file: {fileData.Length} bytes, prot: {protection})");
         }
         finally
         {
@@ -793,6 +805,16 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
             foreach (var region in _regions)
             {
                 var regionEnd = region.VirtualAddress + region.Size;
+                if (region.VirtualAddress >= end)
+                {
+                    break;
+                }
+
+                if (regionEnd <= address)
+                {
+                    continue;
+                }
+
                 if (address < regionEnd && region.VirtualAddress < end)
                 {
                     overlapEnd = Math.Max(overlapEnd, regionEnd);
@@ -807,6 +829,37 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
         return overlapEnd != 0;
     }
 
+    private ulong GetAllocationSearchCursor(
+        ulong desiredAddress,
+        ulong requestedCursor,
+        ulong alignment,
+        bool executable)
+    {
+        lock (_allocationSearchHintGate)
+        {
+            var key = (desiredAddress, alignment, executable);
+            if (_allocationSearchHints.TryGetValue(key, out var hintedCursor) &&
+                hintedCursor > requestedCursor)
+            {
+                return AlignUp(hintedCursor, alignment);
+            }
+        }
+
+        return requestedCursor;
+    }
+
+    private void UpdateAllocationSearchCursor(
+        ulong desiredAddress,
+        ulong alignment,
+        bool executable,
+        ulong nextCursor)
+    {
+        lock (_allocationSearchHintGate)
+        {
+            _allocationSearchHints[(desiredAddress, alignment, executable)] = AlignUp(nextCursor, alignment);
+        }
+    }
+
     private static bool TryResolveRegionOffset(ulong address, ulong size, MemoryRegion region, out ulong offset)
     {
         offset = 0;
@@ -975,6 +1028,29 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
         return checked((value + mask) & ~mask);
     }
 
+    private static ulong ResolveLazyReservePrimeBytes()
+    {
+        var configured = Environment.GetEnvironmentVariable("SHARPEMU_LAZY_RESERVE_PRIME_MB");
+        if (ulong.TryParse(configured, out var megabytes))
+        {
+            return megabytes == 0
+                ? 0
+                : checked(Math.Min(megabytes, 4096UL) * 1024UL * 1024UL);
+        }
+
+        return DefaultLazyReservePrimeBytes;
+    }
+
+    private static void TraceVmem(string message)
+    {
+        if (!string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_VMEM"), "1", StringComparison.Ordinal))
+        {
+            return;
+        }
+
+        Console.Error.WriteLine($"[VMEM] {message}");
+    }
+
     public void Dispose()
     {
         if (!_disposed)

src/SharpEmu.Libs/Ampr/AmprExports.cs

@@ -24,6 +24,7 @@ public static class AmprExports
     private const uint KernelEventQueueRecordType = 2;
     private const uint WriteAddressRecordType = 3;
     private static readonly ConcurrentDictionary<ulong, CommandBufferState> _commandBuffers = new();
+    private static readonly ConcurrentDictionary<string, Lazy<CachedHostFile>> _hostFileCache = new(StringComparer.OrdinalIgnoreCase);
     private static readonly bool _traceAmpr =
         string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_AMPR"), "1", StringComparison.Ordinal);
     private static readonly bool _traceAmprReads =
@@ -37,6 +38,23 @@ public static class AmprExports
         public ulong WriteOffset;
     }
 
+    private sealed class CachedHostFile
+    {
+        public CachedHostFile(string path)
+        {
+            Stream = new FileStream(
+                path,
+                FileMode.Open,
+                FileAccess.Read,
+                FileShare.ReadWrite | FileShare.Delete,
+                bufferSize: 1024 * 1024,
+                FileOptions.RandomAccess);
+        }
+
+        public object Gate { get; } = new();
+        public FileStream Stream { get; }
+    }
+
     [SysAbiExport(
         Nid = "8aI7R7WaOlc",
         ExportName = "sceAmprCommandBufferConstructor",
@@ -249,7 +267,7 @@ public static class AmprExports
             return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT;
         }
 
-        if (!AmprFileRegistry.TryGetHostPath(fileId, out var hostPath) || !File.Exists(hostPath))
+        if (!AmprFileRegistry.TryGetHostPath(fileId, out var hostPath))
         {
             TraceAmprRead(ctx, commandBuffer, fileId, destination, size, fileOffset, bytesRead: 0, hostPath, (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND);
             return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND;
@@ -634,24 +652,43 @@ public static class AmprExports
 
         try
         {
-            using var stream = new FileStream(
+            if (!TryGetCachedHostFile(hostPath, out var cachedFile, out var openResult))
-                hostPath,
+            {
-                FileMode.Open,
+                return openResult;
-                FileAccess.Read,
+            }
-                FileShare.ReadWrite | FileShare.Delete,
+
-                ChunkSize,
+            long fileLength;
-                FileOptions.SequentialScan);
+            lock (cachedFile.Gate)
-            if (fileOffset >= (ulong)stream.Length)
+            {
+                fileLength = cachedFile.Stream.Length;
+            }
+
+            if (fileOffset >= (ulong)fileLength)
             {
                 return (int)OrbisGen2Result.ORBIS_GEN2_OK;
             }
 
-            stream.Position = unchecked((long)fileOffset);
-
             while (bytesRead < size)
             {
+                if (bytesRead > ulong.MaxValue - fileOffset)
+                {
+                    return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_INVALID_ARGUMENT;
+                }
+
+                var absoluteOffset = fileOffset + bytesRead;
+                if (absoluteOffset > long.MaxValue)
+                {
+                    return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_INVALID_ARGUMENT;
+                }
+
                 var request = (int)Math.Min((ulong)buffer.Length, size - bytesRead);
-                var read = stream.Read(buffer, 0, request);
+                int read;
+                lock (cachedFile.Gate)
+                {
+                    cachedFile.Stream.Position = unchecked((long)absoluteOffset);
+                    read = cachedFile.Stream.Read(buffer, 0, request);
+                }
+
                 if (read <= 0)
                 {
                     break;
@@ -681,6 +718,44 @@ public static class AmprExports
         return (int)OrbisGen2Result.ORBIS_GEN2_OK;
     }
 
+    private static bool TryGetCachedHostFile(string hostPath, out CachedHostFile file, out int result)
+    {
+        file = null!;
+        result = (int)OrbisGen2Result.ORBIS_GEN2_OK;
+
+        string cachePath;
+        try
+        {
+            cachePath = Path.GetFullPath(hostPath);
+        }
+        catch
+        {
+            cachePath = hostPath;
+        }
+
+        var lazy = _hostFileCache.GetOrAdd(
+            cachePath,
+            static path => new Lazy<CachedHostFile>(() => new CachedHostFile(path), isThreadSafe: true));
+
+        try
+        {
+            file = lazy.Value;
+            return true;
+        }
+        catch (UnauthorizedAccessException)
+        {
+            _hostFileCache.TryRemove(cachePath, out _);
+            result = (int)OrbisGen2Result.ORBIS_GEN2_ERROR_PERMISSION_DENIED;
+            return false;
+        }
+        catch (IOException)
+        {
+            _hostFileCache.TryRemove(cachePath, out _);
+            result = (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND;
+            return false;
+        }
+    }
+
     private static bool AppendReadFileRecord(
         CpuContext ctx,
         ulong commandBuffer,

src/SharpEmu.Libs/Kernel/KernelEventQueueCompatExports.cs

@@ -276,6 +276,22 @@ public static class KernelEventQueueCompatExports
         var outCountAddress = ctx[CpuRegister.Rcx];
         var timeoutAddress = ctx[CpuRegister.R8];
 
+        if (!IsValidEqueue(handle))
+        {
+            return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND;
+        }
+
+        if (eventsAddress == 0 || eventCapacity < 1)
+        {
+            return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_INVALID_ARGUMENT;
+        }
+
+        uint timeoutUsec = 0;
+        if (timeoutAddress != 0 && !TryReadUInt32(ctx, timeoutAddress, out timeoutUsec))
+        {
+            return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT;
+        }
+
         var deliveredCount = DequeueEvents(ctx, handle, eventsAddress, eventCapacity);
         if (outCountAddress != 0 && !TryWriteUInt32(ctx, outCountAddress, (uint)deliveredCount))
         {
@@ -300,6 +316,41 @@ public static class KernelEventQueueCompatExports
             return (int)OrbisGen2Result.ORBIS_GEN2_OK;
         }
 
+        if (timeoutAddress != 0 && ctx.TryReadUInt64(timeoutAddress, out var timeoutRaw))
+        {
+            var timeoutMicros = timeoutRaw & 0xFFFF_FFFFUL;
+            var deadline = Environment.TickCount64 +
+                Math.Max(1L, (long)Math.Min(timeoutMicros / 1000, int.MaxValue));
+            lock (_eventQueueGate)
+            {
+                while (!HasPendingEvents(handle))
+                {
+                    var remaining = deadline - Environment.TickCount64;
+                    if (remaining <= 0)
+                    {
+                        break;
+                    }
+
+                    Monitor.Wait(_eventQueueGate, (int)Math.Min(remaining, 100));
+                }
+            }
+
+            deliveredCount = DequeueEvents(ctx, handle, eventsAddress, eventCapacity);
+            if (outCountAddress != 0 && !TryWriteUInt32(ctx, outCountAddress, (uint)deliveredCount))
+            {
+                return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT;
+            }
+
+            if (deliveredCount > 0)
+            {
+                TraceEventQueue(ctx, "wait-timed-deliver", handle);
+                return (int)OrbisGen2Result.ORBIS_GEN2_OK;
+            }
+
+            TraceEventQueue(ctx, "wait-timeout", handle);
+            return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_TIMED_OUT;
+        }
+
         TraceEventQueue(ctx, "wait", handle);
         return (int)OrbisGen2Result.ORBIS_GEN2_OK;
     }
@@ -330,6 +381,7 @@ public static class KernelEventQueueCompatExports
 
             queue.AddLast(queuedEvent);
             queued = true;
+            Monitor.PulseAll(_eventQueueGate);
         }
 
         if (queued)
@@ -494,7 +546,9 @@ public static class KernelEventQueueCompatExports
             return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT;
         }
 
-        return (int)OrbisGen2Result.ORBIS_GEN2_OK;
+        return deliveredCount > 0
+            ? (int)OrbisGen2Result.ORBIS_GEN2_OK
+            : (int)OrbisGen2Result.ORBIS_GEN2_ERROR_TIMED_OUT;
     }
 
     private static bool HasPendingEvents(ulong handle)
@@ -612,4 +666,17 @@ public static class KernelEventQueueCompatExports
         BinaryPrimitives.WriteUInt32LittleEndian(buffer, value);
         return ctx.Memory.TryWrite(address, buffer);
     }
+
+    private static bool TryReadUInt32(CpuContext ctx, ulong address, out uint value)
+    {
+        Span<byte> buffer = stackalloc byte[sizeof(uint)];
+        if (!ctx.Memory.TryRead(address, buffer))
+        {
+            value = 0;
+            return false;
+        }
+
+        value = BinaryPrimitives.ReadUInt32LittleEndian(buffer);
+        return true;
+    }
 }

src/SharpEmu.Libs/Kernel/KernelMemoryCompatExports.cs

@@ -5,9 +5,9 @@ using SharpEmu.HLE;
 using SharpEmu.Libs.Ampr;
 using System.Buffers;
 using System.Buffers.Binary;
+using System.Collections.Concurrent;
 using System.Text;
 using System.Threading;
-using System.Reflection;
 using System.Runtime.InteropServices;
 using System.Linq;
 using System.Globalization;
@@ -108,6 +108,7 @@ public static class KernelMemoryCompatExports
     private static readonly Dictionary<string, string> _guestMounts = new(StringComparer.OrdinalIgnoreCase);
     private static readonly HashSet<string> _tracedStatResults = new(StringComparer.Ordinal);
     private static readonly HashSet<string> _negativeStatCache = new(StringComparer.OrdinalIgnoreCase);
+    private static readonly ConcurrentDictionary<string, ulong> _aprFileSizeCache = new(StringComparer.OrdinalIgnoreCase);
     private static long _nextFileDescriptor = 2;
     private static ulong _nextPhysicalAddress;
     private static ulong _nextVirtualAddress;
@@ -1342,6 +1343,7 @@ public static class KernelMemoryCompatExports
             if (IsMutatingOpen(flags))
             {
                 InvalidateNegativeStatCacheForPathAndAncestors(guestPath);
+                InvalidateAprFileSizeCache(hostPath);
             }
 
             LogOpenTrace($"_open file path='{guestPath}' host='{hostPath}' flags=0x{flags:X8} fd={fd}");
@@ -1550,6 +1552,7 @@ public static class KernelMemoryCompatExports
 
             File.Delete(hostPath);
             InvalidateNegativeStatCacheForPathAndAncestors(guestPath);
+            InvalidateAprFileSizeCache(hostPath);
             AddNegativeStatCacheForGuestPath(guestPath);
             LogOpenTrace($"unlink path='{guestPath}' host='{hostPath}'");
             ctx[CpuRegister.Rax] = 0;
@@ -2596,8 +2599,11 @@ public static class KernelMemoryCompatExports
         var length = ctx[CpuRegister.Rsi];
         var protection = unchecked((int)ctx[CpuRegister.Rdx]);
         var flags = ctx[CpuRegister.Rcx];
-        Console.Error.WriteLine(
+        if (ShouldTraceDirectMemory())
-            $"[LOADER][TRACE] map_flexible: inout=0x{inOutAddressPointer:X16} len=0x{length:X16} prot=0x{protection:X8} flags=0x{flags:X16}");
+        {
+            Console.Error.WriteLine(
+                $"[LOADER][TRACE] map_flexible: inout=0x{inOutAddressPointer:X16} len=0x{length:X16} prot=0x{protection:X8} flags=0x{flags:X16}");
+        }
         if (inOutAddressPointer == 0 || length == 0)
         {
             return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_INVALID_ARGUMENT;
@@ -2627,8 +2633,11 @@ public static class KernelMemoryCompatExports
                     : AllocateMappedGuestAddress(ctx, length, 0x1000UL);
             }
 
-            Console.Error.WriteLine(
+            if (ShouldTraceDirectMemory())
-                $"[LOADER][TRACE] map_flexible reserve: requested=0x{requestedAddress:X16} desired=0x{desiredAddress:X16} mapped=0x{mappedAddress:X16}");
+            {
+                Console.Error.WriteLine(
+                    $"[LOADER][TRACE] map_flexible reserve: requested=0x{requestedAddress:X16} desired=0x{desiredAddress:X16} mapped=0x{mappedAddress:X16}");
+            }
 
             if (mappedAddress == 0)
             {
@@ -3973,118 +3982,17 @@ public static class KernelMemoryCompatExports
         ulong alignment,
         out ulong mappedAddress)
     {
-        mappedAddress = 0;
+        var executable = (protection & OrbisProtCpuExec) != 0;
-        if (length == 0)
+        return KernelVirtualRangeAllocator.TryReserve(
-        {
+            ctx,
-            return false;
+            desiredAddress,
-        }
+            length,
-
+            executable,
-        try
+            alignment,
-        {
+            allowSearch: true,
-            object memoryObject = ctx.Memory;
+            allowAllocateAtAlternative: false,
-            MethodInfo? allocateAt = null;
+            "reserve range",
-            MethodInfo? allocateAtOrAbove = null;
+            out mappedAddress);
-            var allocateAtHasAllowAlternativeArg = false;
-            for (var depth = 0; depth < 4; depth++)
-            {
-                foreach (var candidate in memoryObject.GetType().GetMethods(BindingFlags.Public | BindingFlags.Instance))
-                {
-                    var parameters = candidate.GetParameters();
-                    if (string.Equals(candidate.Name, "TryAllocateAtOrAbove", StringComparison.Ordinal) &&
-                        parameters.Length == 5 &&
-                        parameters[0].ParameterType == typeof(ulong) &&
-                        parameters[1].ParameterType == typeof(ulong) &&
-                        parameters[2].ParameterType == typeof(bool) &&
-                        parameters[3].ParameterType == typeof(ulong) &&
-                        parameters[4].ParameterType == typeof(ulong).MakeByRefType())
-                    {
-                        allocateAtOrAbove = candidate;
-                    }
-                    else if (string.Equals(candidate.Name, "AllocateAt", StringComparison.Ordinal))
-                    {
-                        if (parameters.Length == 3 &&
-                            parameters[0].ParameterType == typeof(ulong) &&
-                            parameters[1].ParameterType == typeof(ulong) &&
-                            parameters[2].ParameterType == typeof(bool))
-                        {
-                            allocateAt = candidate;
-                            allocateAtHasAllowAlternativeArg = false;
-                        }
-                        else if (parameters.Length == 4 &&
-                            parameters[0].ParameterType == typeof(ulong) &&
-                            parameters[1].ParameterType == typeof(ulong) &&
-                            parameters[2].ParameterType == typeof(bool) &&
-                            parameters[3].ParameterType == typeof(bool))
-                        {
-                            allocateAt = candidate;
-                            allocateAtHasAllowAlternativeArg = true;
-                        }
-                    }
-
-                    if (allocateAtOrAbove is not null && allocateAt is not null)
-                    {
-                        break;
-                    }
-                }
-
-                if (allocateAtOrAbove is not null || allocateAt is not null)
-                {
-                    break;
-                }
-
-                var innerProperty = memoryObject.GetType().GetProperty("Inner", BindingFlags.Public | BindingFlags.Instance);
-                if (innerProperty is null)
-                {
-                    break;
-                }
-
-                var innerValue = innerProperty.GetValue(memoryObject);
-                if (innerValue is null || ReferenceEquals(innerValue, memoryObject))
-                {
-                    break;
-                }
-
-                memoryObject = innerValue;
-            }
-
-            var executable = (protection & OrbisProtCpuExec) != 0;
-            if (allocateAtOrAbove is not null)
-            {
-                var searchArgs = new object[] { desiredAddress, length, executable, alignment, 0UL };
-                var searchResult = allocateAtOrAbove.Invoke(memoryObject, searchArgs);
-                if (searchResult is bool trueValue && trueValue &&
-                    searchArgs[4] is ulong searchedAddress && searchedAddress != 0)
-                {
-                    mappedAddress = searchedAddress;
-                    return true;
-                }
-            }
-
-            if (allocateAt is null)
-            {
-                Console.Error.WriteLine($"[LOADER][TRACE] reserve range: AllocateAt missing on {ctx.Memory.GetType().FullName}");
-                return false;
-            }
-
-            var invokeArgs = allocateAtHasAllowAlternativeArg
-                ? new object[] { desiredAddress, length, executable, false }
-                : new object[] { desiredAddress, length, executable };
-            var result = allocateAt.Invoke(memoryObject, invokeArgs);
-            if (result is not ulong allocated || allocated == 0)
-            {
-                var resultType = result?.GetType().FullName ?? "null";
-                Console.Error.WriteLine($"[LOADER][TRACE] reserve range: AllocateAt returned {resultType} value={result ?? "null"}");
-                return false;
-            }
-
-            mappedAddress = allocated;
-            return true;
-        }
-        catch
-        {
-            Console.Error.WriteLine("[LOADER][TRACE] reserve range threw while invoking AllocateAt");
-            return false;
-        }
     }
 
     private static bool IsMappedGuestRangeAvailable(
@@ -4237,6 +4145,20 @@ public static class KernelMemoryCompatExports
         var app0Root = ResolveApp0Root();
         if (!string.IsNullOrWhiteSpace(app0Root))
         {
+            if (string.Equals(guestPath, "$", StringComparison.Ordinal) ||
+                string.Equals(guestPath, "$/", StringComparison.Ordinal) ||
+                string.Equals(guestPath, "$\\", StringComparison.Ordinal))
+            {
+                return app0Root;
+            }
+
+            if (guestPath.StartsWith("$/", StringComparison.Ordinal) ||
+                guestPath.StartsWith("$\\", StringComparison.Ordinal))
+            {
+                var relative = NormalizeMountRelativePath(guestPath[2..]);
+                return Path.Combine(app0Root, relative);
+            }
+
             if (string.Equals(guestPath, "/app0", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(guestPath, "app0", StringComparison.OrdinalIgnoreCase))
             {
@@ -5899,22 +5821,40 @@ public static class KernelMemoryCompatExports
     private static bool TryGetAprFileSize(string hostPath, out ulong size)
     {
         size = 0;
+
+        string cachePath;
         try
         {
-            var fileInfo = new FileInfo(hostPath);
+            cachePath = Path.GetFullPath(hostPath);
+        }
+        catch
+        {
+            cachePath = hostPath;
+        }
+
+        if (_aprFileSizeCache.TryGetValue(cachePath, out size))
+        {
+            return true;
+        }
+
+        try
+        {
+            var fileInfo = new FileInfo(cachePath);
             if (fileInfo.Exists)
             {
                 var length = fileInfo.Length;
                 size = length < 0 ? 0UL : unchecked((ulong)length);
+                _aprFileSizeCache.TryAdd(cachePath, size);
                 return true;
             }
 
-            if (!new DirectoryInfo(hostPath).Exists)
+            if (!new DirectoryInfo(cachePath).Exists)
             {
                 return false;
             }
 
             size = 65536;
+            _aprFileSizeCache.TryAdd(cachePath, size);
             return true;
         }
         catch
@@ -6213,6 +6153,20 @@ public static class KernelMemoryCompatExports
         }
     }
 
+    private static void InvalidateAprFileSizeCache(string hostPath)
+    {
+        try
+        {
+            hostPath = Path.GetFullPath(hostPath);
+        }
+        catch
+        {
+            // The cache key remains the original path when normalization fails.
+        }
+
+        _aprFileSizeCache.TryRemove(hostPath, out _);
+    }
+
     private static string PreviewIoBytes(byte[] buffer, int count, int maxBytes)
     {
         if (count <= 0)

src/SharpEmu.Libs/Kernel/KernelRuntimeCompatExports.cs

@@ -7,7 +7,6 @@ using System.Buffers.Binary;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
-using System.Reflection;
 using System.Runtime.InteropServices;
 using System.Runtime.Intrinsics.X86;
 using System.Security.Cryptography;
@@ -87,11 +86,11 @@ public static class KernelRuntimeCompatExports
 
         if (micros < 1000)
         {
-            // Guest worker pools use usleep(1) as a polling backoff. Periodically
+            // Guest worker pools use usleep(1) as a polling backoff. Do not turn
-            // relinquish a full host time slice so spin workers cannot starve producers.
+            // PS microsecond waits into Windows millisecond sleeps on hot paths.
-            if ((++_shortUsleepCount & 31) == 0)
+            if ((++_shortUsleepCount & 255) == 0)
             {
-                Thread.Sleep(1);
+                Thread.Sleep(0);
             }
             else
             {
@@ -739,8 +738,11 @@ public static class KernelRuntimeCompatExports
             return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND;
         }
 
-        Console.Error.WriteLine(
+        if (ShouldTraceVirtualMemory())
-            $"[LOADER][TRACE] reserve_virtual_range: req=0x{requestedAddress:X16} desired=0x{desiredAddress:X16} mapped=0x{mappedAddress:X16} len=0x{length:X16} flags=0x{flags:X8} align=0x{effectiveAlignment:X16}");
+        {
+            Console.Error.WriteLine(
+                $"[LOADER][TRACE] reserve_virtual_range: req=0x{requestedAddress:X16} desired=0x{desiredAddress:X16} mapped=0x{mappedAddress:X16} len=0x{length:X16} flags=0x{flags:X8} align=0x{effectiveAlignment:X16}");
+        }
 
         if (!ctx.TryWriteUInt64(inOutAddressPointer, mappedAddress))
         {
@@ -1733,117 +1735,16 @@ public static class KernelRuntimeCompatExports
         bool allowSearch,
         out ulong mappedAddress)
     {
-        mappedAddress = 0;
+        return KernelVirtualRangeAllocator.TryReserve(
-        if (length == 0)
+            ctx,
-        {
+            desiredAddress,
-            return false;
+            length,
-        }
+            executable: false,
-
+            alignment,
-        try
+            allowSearch,
-        {
+            allowAllocateAtAlternative: allowSearch,
-            object memoryObject = ctx.Memory;
+            "reserve_virtual_range",
-            MethodInfo? allocateAt = null;
+            out mappedAddress);
-            MethodInfo? allocateAtOrAbove = null;
-            var allocateAtHasAllowAlternativeArg = false;
-            for (var depth = 0; depth < 4; depth++)
-            {
-                foreach (var candidate in memoryObject.GetType().GetMethods(BindingFlags.Public | BindingFlags.Instance))
-                {
-                    var parameters = candidate.GetParameters();
-                    if (string.Equals(candidate.Name, "TryAllocateAtOrAbove", StringComparison.Ordinal) &&
-                        parameters.Length == 5 &&
-                        parameters[0].ParameterType == typeof(ulong) &&
-                        parameters[1].ParameterType == typeof(ulong) &&
-                        parameters[2].ParameterType == typeof(bool) &&
-                        parameters[3].ParameterType == typeof(ulong) &&
-                        parameters[4].ParameterType == typeof(ulong).MakeByRefType())
-                    {
-                        allocateAtOrAbove = candidate;
-                    }
-                    else if (string.Equals(candidate.Name, "AllocateAt", StringComparison.Ordinal))
-                    {
-                        if (parameters.Length == 3 &&
-                            parameters[0].ParameterType == typeof(ulong) &&
-                            parameters[1].ParameterType == typeof(ulong) &&
-                            parameters[2].ParameterType == typeof(bool))
-                        {
-                            allocateAt = candidate;
-                            allocateAtHasAllowAlternativeArg = false;
-                        }
-                        else if (parameters.Length == 4 &&
-                            parameters[0].ParameterType == typeof(ulong) &&
-                            parameters[1].ParameterType == typeof(ulong) &&
-                            parameters[2].ParameterType == typeof(bool) &&
-                            parameters[3].ParameterType == typeof(bool))
-                        {
-                            allocateAt = candidate;
-                            allocateAtHasAllowAlternativeArg = true;
-                        }
-                    }
-
-                    if (allocateAtOrAbove is not null && allocateAt is not null)
-                    {
-                        break;
-                    }
-                }
-
-                if (allocateAtOrAbove is not null || allocateAt is not null)
-                {
-                    break;
-                }
-
-                var innerProperty = memoryObject.GetType().GetProperty("Inner", BindingFlags.Public | BindingFlags.Instance);
-                if (innerProperty is null)
-                {
-                    break;
-                }
-
-                var innerValue = innerProperty.GetValue(memoryObject);
-                if (innerValue is null || ReferenceEquals(innerValue, memoryObject))
-                {
-                    break;
-                }
-
-                memoryObject = innerValue;
-            }
-
-            if (allowSearch && allocateAtOrAbove is not null)
-            {
-                var searchArgs = new object[] { desiredAddress, length, false, alignment, 0UL };
-                var searchResult = allocateAtOrAbove.Invoke(memoryObject, searchArgs);
-                if (searchResult is bool trueValue && trueValue &&
-                    searchArgs[4] is ulong searchedAddress && searchedAddress != 0)
-                {
-                    mappedAddress = searchedAddress;
-                    return true;
-                }
-            }
-
-            if (allocateAt is null)
-            {
-                Console.Error.WriteLine($"[LOADER][TRACE] reserve_virtual_range: AllocateAt missing on {ctx.Memory.GetType().FullName}");
-                return false;
-            }
-
-            var invokeArgs = allocateAtHasAllowAlternativeArg
-                ? new object[] { desiredAddress, length, false, allowSearch }
-                : new object[] { desiredAddress, length, false };
-            var result = allocateAt.Invoke(memoryObject, invokeArgs);
-            if (result is not ulong allocated || allocated == 0)
-            {
-                var resultType = result?.GetType().FullName ?? "null";
-                Console.Error.WriteLine($"[LOADER][TRACE] reserve_virtual_range: AllocateAt returned {resultType} value={result ?? "null"}");
-                return false;
-            }
-
-            mappedAddress = allocated;
-            return true;
-        }
-        catch
-        {
-            Console.Error.WriteLine("[LOADER][TRACE] reserve_virtual_range: AllocateAt invocation threw");
-            return false;
-        }
     }
 
     private static ulong AlignUp(ulong value, ulong alignment)
@@ -1856,4 +1757,9 @@ public static class KernelRuntimeCompatExports
         var mask = alignment - 1;
         return (value + mask) & ~mask;
     }
+
+    private static bool ShouldTraceVirtualMemory()
+    {
+        return string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_VIRTUAL_MEMORY"), "1", StringComparison.Ordinal);
+    }
 }

src/SharpEmu.Libs/Kernel/KernelVirtualRangeAllocator.cs

@@ -0,0 +1,159 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.HLE;
+using System;
+using System.Collections.Concurrent;
+using System.Reflection;
+
+namespace SharpEmu.Libs.Kernel;
+
+internal static class KernelVirtualRangeAllocator
+{
+    private static readonly ConcurrentDictionary<Type, Accessor> _accessors = new();
+
+    public static bool TryReserve(
+        CpuContext ctx,
+        ulong desiredAddress,
+        ulong length,
+        bool executable,
+        ulong alignment,
+        bool allowSearch,
+        bool allowAllocateAtAlternative,
+        string traceName,
+        out ulong mappedAddress)
+    {
+        mappedAddress = 0;
+        if (length == 0)
+        {
+            return false;
+        }
+
+        try
+        {
+            if (!TryResolveAccessor(ctx.Memory, out var target, out var accessor))
+            {
+                Console.Error.WriteLine($"[LOADER][TRACE] {traceName}: AllocateAt missing on {ctx.Memory.GetType().FullName}");
+                return false;
+            }
+
+            if (allowSearch && accessor.AllocateAtOrAbove is not null)
+            {
+                var searchArgs = new object[] { desiredAddress, length, executable, alignment, 0UL };
+                var searchResult = accessor.AllocateAtOrAbove.Invoke(target, searchArgs);
+                if (searchResult is bool trueValue && trueValue &&
+                    searchArgs[4] is ulong searchedAddress && searchedAddress != 0)
+                {
+                    mappedAddress = searchedAddress;
+                    return true;
+                }
+            }
+
+            if (accessor.AllocateAt is null)
+            {
+                Console.Error.WriteLine($"[LOADER][TRACE] {traceName}: AllocateAt missing on {target.GetType().FullName}");
+                return false;
+            }
+
+            var invokeArgs = accessor.AllocateAtHasAllowAlternativeArg
+                ? new object[] { desiredAddress, length, executable, allowAllocateAtAlternative }
+                : new object[] { desiredAddress, length, executable };
+            var result = accessor.AllocateAt.Invoke(target, invokeArgs);
+            if (result is not ulong allocated || allocated == 0)
+            {
+                var resultType = result?.GetType().FullName ?? "null";
+                Console.Error.WriteLine($"[LOADER][TRACE] {traceName}: AllocateAt returned {resultType} value={result ?? "null"}");
+                return false;
+            }
+
+            mappedAddress = allocated;
+            return true;
+        }
+        catch
+        {
+            Console.Error.WriteLine($"[LOADER][TRACE] {traceName}: AllocateAt invocation threw");
+            return false;
+        }
+    }
+
+    private static bool TryResolveAccessor(object rootMemory, out object target, out Accessor accessor)
+    {
+        target = rootMemory;
+        accessor = default;
+
+        for (var depth = 0; depth < 4; depth++)
+        {
+            accessor = _accessors.GetOrAdd(target.GetType(), DiscoverAccessor);
+            if (accessor.AllocateAt is not null || accessor.AllocateAtOrAbove is not null)
+            {
+                return true;
+            }
+
+            if (accessor.InnerProperty is null)
+            {
+                break;
+            }
+
+            var innerValue = accessor.InnerProperty.GetValue(target);
+            if (innerValue is null || ReferenceEquals(innerValue, target))
+            {
+                break;
+            }
+
+            target = innerValue;
+        }
+
+        return false;
+    }
+
+    private static Accessor DiscoverAccessor(Type type)
+    {
+        MethodInfo? allocateAt = null;
+        MethodInfo? allocateAtOrAbove = null;
+        var allocateAtHasAllowAlternativeArg = false;
+
+        foreach (var candidate in type.GetMethods(BindingFlags.Public | BindingFlags.Instance))
+        {
+            var parameters = candidate.GetParameters();
+            if (string.Equals(candidate.Name, "TryAllocateAtOrAbove", StringComparison.Ordinal) &&
+                parameters.Length == 5 &&
+                parameters[0].ParameterType == typeof(ulong) &&
+                parameters[1].ParameterType == typeof(ulong) &&
+                parameters[2].ParameterType == typeof(bool) &&
+                parameters[3].ParameterType == typeof(ulong) &&
+                parameters[4].ParameterType == typeof(ulong).MakeByRefType())
+            {
+                allocateAtOrAbove = candidate;
+            }
+            else if (string.Equals(candidate.Name, "AllocateAt", StringComparison.Ordinal))
+            {
+                if (parameters.Length == 3 &&
+                    parameters[0].ParameterType == typeof(ulong) &&
+                    parameters[1].ParameterType == typeof(ulong) &&
+                    parameters[2].ParameterType == typeof(bool))
+                {
+                    allocateAt = candidate;
+                    allocateAtHasAllowAlternativeArg = false;
+                }
+                else if (parameters.Length == 4 &&
+                    parameters[0].ParameterType == typeof(ulong) &&
+                    parameters[1].ParameterType == typeof(ulong) &&
+                    parameters[2].ParameterType == typeof(bool) &&
+                    parameters[3].ParameterType == typeof(bool))
+                {
+                    allocateAt = candidate;
+                    allocateAtHasAllowAlternativeArg = true;
+                }
+            }
+        }
+
+        var innerProperty = type.GetProperty("Inner", BindingFlags.Public | BindingFlags.Instance);
+        return new Accessor(allocateAt, allocateAtOrAbove, allocateAtHasAllowAlternativeArg, innerProperty);
+    }
+
+    private readonly record struct Accessor(
+        MethodInfo? AllocateAt,
+        MethodInfo? AllocateAtOrAbove,
+        bool AllocateAtHasAllowAlternativeArg,
+        PropertyInfo? InnerProperty);
+}

src/SharpEmu.Libs/VideoOut/VulkanVideoPresenter.cs

@@ -879,6 +879,8 @@ internal static unsafe class VulkanVideoPresenter
         private bool _swapchainRecreateDeferred;
         private bool _tracedPresentedSwapchain;
         private bool _swapchainReadbackPending;
+        private bool _deviceLost;
+        private bool _deviceLostLogged;
         private int _directPresentationCount;
         private readonly Dictionary<ulong, GuestImageResource> _guestImages = new();
         private readonly HashSet<(ulong Address, uint Width, uint Height, Format Format)> _tracedTextureCacheHits = new();
@@ -2816,7 +2818,8 @@ internal static unsafe class VulkanVideoPresenter
                     dstSelect: texture.DstSelect,
                     out var view))
             {
-                if (_tracedTextureCacheHits.Add(
+                if (ShouldTraceVulkanResources() &&
+                    _tracedTextureCacheHits.Add(
                         (texture.Address, texture.Width, texture.Height, vkFormat)))
                 {
                     Console.Error.WriteLine(
@@ -3395,7 +3398,8 @@ internal static unsafe class VulkanVideoPresenter
                 out var memory);
             var size = (ulong)Math.Max(guestBuffer.Data.Length, sizeof(uint));
 
-            if (_tracedGlobalBuffers.Add((guestBuffer.BaseAddress, guestBuffer.Data.Length)))
+            if (ShouldTraceVulkanResources() &&
+                _tracedGlobalBuffers.Add((guestBuffer.BaseAddress, guestBuffer.Data.Length)))
             {
                 Console.Error.WriteLine(
                     $"[LOADER][TRACE] vk.global_buffer base=0x{guestBuffer.BaseAddress:X16} " +
@@ -4030,6 +4034,11 @@ internal static unsafe class VulkanVideoPresenter
 
         private void ExecuteComputeDispatch(VulkanComputeGuestDispatch work)
         {
+            if (_deviceLost)
+            {
+                return;
+            }
+
             if (AddressListContains("SHARPEMU_SKIP_COMPUTE_CS", work.ShaderAddress))
             {
                 TraceVulkanShader(
@@ -4132,6 +4141,11 @@ internal static unsafe class VulkanVideoPresenter
             }
             catch (Exception exception)
             {
+                if (TryMarkDeviceLost(exception))
+                {
+                    return;
+                }
+
                 Console.Error.WriteLine(
                     $"[LOADER][ERROR] Vulkan compute dispatch failed " +
                     $"cs=0x{work.ShaderAddress:X16}: {exception.Message}");
@@ -4197,6 +4211,11 @@ internal static unsafe class VulkanVideoPresenter
 
         private void ExecuteOffscreenDraw(VulkanOffscreenGuestDraw work)
         {
+            if (_deviceLost)
+            {
+                return;
+            }
+
             var format = GetRenderTargetFormat(work.Target.Format, work.Target.NumberType);
             if (format == Format.Undefined)
             {
@@ -4354,6 +4373,11 @@ internal static unsafe class VulkanVideoPresenter
             }
             catch (Exception exception)
             {
+                if (TryMarkDeviceLost(exception))
+                {
+                    return;
+                }
+
                 if (!_guestImages.TryGetValue(work.Target.Address, out var failedTarget) ||
                     !failedTarget.Initialized)
                 {
@@ -4809,7 +4833,10 @@ internal static unsafe class VulkanVideoPresenter
             }
 
             _commandBuffer = _presentationCommandBuffer;
-            CollectCompletedGuestSubmissions(waitForOldest: false);
+            if (!_deviceLost)
+            {
+                CollectCompletedGuestSubmissions(waitForOldest: false);
+            }
 
             var completedWork = 0;
             while (completedWork < MaxGuestWorkPerRender &&
@@ -5667,6 +5694,12 @@ internal static unsafe class VulkanVideoPresenter
                    string.Equals(mode, "present", StringComparison.OrdinalIgnoreCase);
         }
 
+        private static bool ShouldTraceVulkanResources() =>
+            string.Equals(
+                Environment.GetEnvironmentVariable("SHARPEMU_LOG_VK_RESOURCES"),
+                "1",
+                StringComparison.Ordinal);
+
         private void RecordTranslatedGraphicsPass(
             TranslatedDrawResources resources,
             RenderPass renderPass,
@@ -6502,6 +6535,25 @@ internal static unsafe class VulkanVideoPresenter
             }
         }
 
+        private bool TryMarkDeviceLost(Exception exception)
+        {
+            if (!exception.Message.Contains(nameof(Result.ErrorDeviceLost), StringComparison.Ordinal))
+            {
+                return false;
+            }
+
+            _deviceLost = true;
+            if (!_deviceLostLogged)
+            {
+                _deviceLostLogged = true;
+                Console.Error.WriteLine(
+                    "[LOADER][ERROR] Vulkan device lost; dropping subsequent guest GPU work. " +
+                    exception.Message);
+            }
+
+            return true;
+        }
+
         private static void TraceVulkanShader(string message)
         {
             if (!string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_AGC"), "1", StringComparison.Ordinal) &&