From 1c0945e4ae0924c41e388b76d57a60b4c3c9d6cb Mon Sep 17 00:00:00 2001
From: Stephen Miller <millerste004@gmail.com>
Date: Mon, 26 May 2025 15:50:25 -0500
Subject: [PATCH] Only perform GPU memory mapping when GPU can access it

This better aligns with hardware observations, and should also speed up unmaps and decommits, since they don't need to be compared with the GPU max address anymore.
---
 src/core/memory.cpp | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/src/core/memory.cpp b/src/core/memory.cpp
index ca6a0d6cd..4ddbfa6bd 100644
--- a/src/core/memory.cpp
+++ b/src/core/memory.cpp
@@ -344,7 +344,10 @@ int MemoryManager::PoolCommit(VAddr virtual_addr, size_t size, MemoryProt prot)
     void* out_addr = impl.Map(mapped_addr, size, alignment, -1, false);
     TRACK_ALLOC(out_addr, size, "VMEM");
 
-    if (IsValidGpuMapping(mapped_addr, size)) {
+    if (prot >= MemoryProt::GpuRead) {
+        // PS4s only map to GPU memory when the protection includes GPU access.
+        // If the address to map to is too high, PS4s throw a page fault and crash.
+        ASSERT_MSG(IsValidGpuMapping(mapped_addr, size), "Invalid address for GPU mapping");
         rasterizer->MapMemory(mapped_addr, size);
     }
 
@@ -420,7 +423,10 @@ int MemoryManager::MapMemory(void** out_addr, VAddr virtual_addr, size_t size, M
         flexible_usage += size;
     }
 
-    if (IsValidGpuMapping(mapped_addr, size)) {
+    if (prot >= MemoryProt::GpuRead) {
+        // PS4s only map to GPU memory when the protection includes GPU access.
+        // If the address to map to is too high, PS4s throw a page fault and crash.
+        ASSERT_MSG(IsValidGpuMapping(mapped_addr, size), "Invalid address for GPU mapping");
         rasterizer->MapMemory(mapped_addr, size);
     }
 
@@ -452,6 +458,13 @@ int MemoryManager::MapFile(void** out_addr, VAddr virtual_addr, size_t size, Mem
     // Map the file.
     impl.MapFile(mapped_addr, size_aligned, offset, std::bit_cast<u32>(prot), fd);
 
+    if (prot >= MemoryProt::GpuRead) {
+        // PS4s only map to GPU memory when the protection includes GPU access.
+        // If the address to map to is too high, PS4s throw a page fault and crash.
+        ASSERT_MSG(IsValidGpuMapping(mapped_addr, size_aligned), "Invalid address for GPU mapping");
+        rasterizer->MapMemory(mapped_addr, size_aligned);
+    }
+
     // Add virtual memory area
     auto& new_vma = CarveVMA(mapped_addr, size_aligned)->second;
     new_vma.disallow_merge = True(flags & MemoryMapFlags::NoCoalesce);
@@ -478,6 +491,7 @@ s32 MemoryManager::PoolDecommit(VAddr virtual_addr, size_t size) {
     const bool is_exec = vma_base.is_exec;
     const auto start_in_vma = virtual_addr - vma_base_addr;
     const auto type = vma_base.type;
+    const auto prot = vma_base.prot;
 
     if (type != VMAType::PoolReserved && type != VMAType::Pooled) {
         LOG_ERROR(Kernel_Vmm, "Attempting to decommit non-pooled memory!");
@@ -489,7 +503,8 @@ s32 MemoryManager::PoolDecommit(VAddr virtual_addr, size_t size) {
         pool_budget += size;
     }
 
-    if (IsValidGpuMapping(virtual_addr, size)) {
+    if (prot >= MemoryProt::GpuRead) {
+        // If this mapping has GPU access, unmap from GPU.
         rasterizer->UnmapMemory(virtual_addr, size);
     }
 
@@ -528,6 +543,7 @@ u64 MemoryManager::UnmapBytesFromEntry(VAddr virtual_addr, VirtualMemoryArea vma
     const auto adjusted_size =
         vma_base_size - start_in_vma < size ? vma_base_size - start_in_vma : size;
     const bool has_backing = type == VMAType::Direct || type == VMAType::File;
+    const auto prot = vma_base.prot;
 
     if (type == VMAType::Free) {
         return adjusted_size;
@@ -536,8 +552,9 @@ u64 MemoryManager::UnmapBytesFromEntry(VAddr virtual_addr, VirtualMemoryArea vma
         flexible_usage -= adjusted_size;
     }
 
-    if (IsValidGpuMapping(virtual_addr, adjusted_size)) {
-        rasterizer->UnmapMemory(virtual_addr, adjusted_size);
+    if (prot >= MemoryProt::GpuRead) {
+        // If this mapping has GPU access, unmap from GPU.
+        rasterizer->UnmapMemory(virtual_addr, size);
     }
 
     // Mark region as free and attempt to coalesce it with neighbours.