core/memory: Create a special MapMemoryRegion for physical memory.

This allows us to create a fastmem arena within the memory.cpp helpers.

src/core/hle/kernel/physical_memory.h

@@ -14,6 +14,9 @@ namespace Kernel {
 // - Second to ensure all host backing memory used is aligned to 256 bytes due
 // to strict alignment restrictions on GPU memory.
 
-using PhysicalMemory = std::vector<u8, Common::AlignmentAllocator<u8, 256>>;
+using PhysicalMemoryVector = std::vector<u8, Common::AlignmentAllocator<u8, 256>>;
+class PhysicalMemory final : public PhysicalMemoryVector {
+    using PhysicalMemoryVector::PhysicalMemoryVector;
+};
 
 } // namespace Kernel

src/core/hle/kernel/vm_manager.cpp

@@ -780,8 +780,7 @@ void VMManager::UpdatePageTableForVMA(const VirtualMemoryArea& vma) {
         memory.UnmapRegion(page_table, vma.base, vma.size);
         break;
     case VMAType::AllocatedMemoryBlock:
-        memory.MapMemoryRegion(page_table, vma.base, vma.size,
-                               vma.backing_block->data() + vma.offset);
+        memory.MapMemoryRegion(page_table, vma.base, vma.size, *vma.backing_block, vma.offset);
         break;
     case VMAType::BackingMemory:
         memory.MapMemoryRegion(page_table, vma.base, vma.size, vma.backing_memory);

src/core/memory.cpp

@@ -14,6 +14,7 @@
 #include "common/swap.h"
 #include "core/arm/arm_interface.h"
 #include "core/core.h"
+#include "core/hle/kernel/physical_memory.h"
 #include "core/hle/kernel/process.h"
 #include "core/hle/kernel/vm_manager.h"
 #include "core/memory.h"
@@ -38,6 +39,11 @@ struct Memory::Impl {
         system.ArmInterface(3).PageTableChanged(*current_page_table, address_space_width);
     }
 
+    void MapMemoryRegion(Common::PageTable& page_table, VAddr base, u64 size,
+                         Kernel::PhysicalMemory& memory, VAddr offset) {
+        MapMemoryRegion(page_table, base, size, memory.data() + offset);
+    }
+
     void MapMemoryRegion(Common::PageTable& page_table, VAddr base, u64 size, u8* target) {
         ASSERT_MSG((size & PAGE_MASK) == 0, "non-page aligned size: {:016X}", size);
         ASSERT_MSG((base & PAGE_MASK) == 0, "non-page aligned base: {:016X}", base);
@@ -601,6 +607,11 @@ void Memory::SetCurrentPageTable(Kernel::Process& process) {
     impl->SetCurrentPageTable(process);
 }
 
+void Memory::MapMemoryRegion(Common::PageTable& page_table, VAddr base, u64 size,
+                             Kernel::PhysicalMemory& memory, VAddr offset) {
+    impl->MapMemoryRegion(page_table, base, size, memory, offset);
+}
+
 void Memory::MapMemoryRegion(Common::PageTable& page_table, VAddr base, u64 size, u8* target) {
     impl->MapMemoryRegion(page_table, base, size, target);
 }

src/core/memory.h

@@ -19,8 +19,9 @@ class System;
 }
 
 namespace Kernel {
+class PhysicalMemory;
 class Process;
-}
+} // namespace Kernel
 
 namespace Memory {
 
@@ -65,6 +66,19 @@ public:
      */
     void SetCurrentPageTable(Kernel::Process& process);
 
+    /**
+     * Maps an physical buffer onto a region of the emulated process address space.
+     *
+     * @param page_table The page table of the emulated process.
+     * @param base       The address to start mapping at. Must be page-aligned.
+     * @param size       The amount of bytes to map. Must be page-aligned.
+     * @param memory     Physical buffer with the memory backing the mapping. Must be of length
+     *                   at least `size + offset`.
+     * @param offset     The offset within the physical memory. Must be page-aligned.
+     */
+    void MapMemoryRegion(Common::PageTable& page_table, VAddr base, u64 size,
+                         Kernel::PhysicalMemory& memory, VAddr offset);
+
     /**
      * Maps an allocated buffer onto a region of the emulated process address space.
      *