Implement MapPhysicalMemory/UnmapPhysicalMemory

This implements svcMapPhysicalMemory/svcUnmapPhysicalMemory for Yuzu,
which can be used to map memory at a desired address by games since
3.0.0.

It also properly parses SystemResourceSize from NPDM, and makes
information available via svcGetInfo.

This is needed for games like Super Smash Bros. and Diablo 3 -- this
PR's implementation does not run into the "ASCII reads" issue mentioned
in the comments of #2626, which was caused by the following bugs in
Yuzu's memory management that this PR also addresses:
* Yuzu's memory coalescing does not properly merge blocks. This results
  in a polluted address space/svcQueryMemory results that would be
  impossible to replicate on hardware, which can lead to game code making
  the wrong assumptions about memory layout.
  * This implements better merging for AllocatedMemoryBlocks.
* Yuzu's implementation of svcMirrorMemory unprotected the entire
  virtual memory range containing the range being mirrored. This could
  lead to games attempting to map data at that unprotected
  range/attempting to access that range after yuzu improperly unmapped
  it.
  * This PR fixes it by simply calling ReprotectRange instead of
    Reprotect.

src/core/hle/kernel/vm_manager.h

@@ -349,7 +349,8 @@ public:
      * @param state MemoryState tag to attach to the VMA.
      */
     ResultVal<VMAHandle> MapMemoryBlock(VAddr target, std::shared_ptr<std::vector<u8>> block,
-                                        std::size_t offset, u64 size, MemoryState state);
+                                        std::size_t offset, u64 size, MemoryState state,
+                                        VMAPermission perm = VMAPermission::ReadWrite);
 
     /**
      * Maps an unmanaged host memory pointer at a given address.
@@ -450,6 +451,34 @@ public:
     ///
     ResultVal<VAddr> SetHeapSize(u64 size);
 
+    /// Maps memory at a given address.
+    ///
+    /// @param addr The virtual address to map memory at.
+    /// @param size The amount of memory to map.
+    ///
+    /// @note The destination address must lie within the Map region.
+    ///
+    /// @note This function requires SystemResourceSize is non-zero,
+    ///       however, this is just because if it were not then the
+    ///       resulting page tables could be exploited on hardware by
+    ///       a malicious program. SystemResource usage does not need
+    ///       to be explicitly checked or updated here.
+    ResultCode MapPhysicalMemory(VAddr target, u64 size);
+
+    /// Unmaps memory at a given address.
+    ///
+    /// @param addr The virtual address to unmap memory at.
+    /// @param size The amount of memory to unmap.
+    ///
+    /// @note The destination address must lie within the Map region.
+    ///
+    /// @note This function requires SystemResourceSize is non-zero,
+    ///       however, this is just because if it were not then the
+    ///       resulting page tables could be exploited on hardware by
+    ///       a malicious program. SystemResource usage does not need
+    ///       to be explicitly checked or updated here.
+    ResultCode UnmapPhysicalMemory(VAddr target, u64 size);
+
     /// Maps a region of memory as code memory.
     ///
     /// @param dst_address The base address of the region to create the aliasing memory region.
@@ -657,6 +686,11 @@ private:
      */
     VMAIter MergeAdjacent(VMAIter vma);
 
+    /**
+     * Merges two adjacent VMAs.
+     */
+    void MergeAdjacentVMA(VirtualMemoryArea& left, const VirtualMemoryArea& right);
+
     /// Updates the pages corresponding to this VMA so they match the VMA's attributes.
     void UpdatePageTableForVMA(const VirtualMemoryArea& vma);
 
@@ -742,6 +776,11 @@ private:
     // end of the range. This is essentially 'base_address + current_size'.
     VAddr heap_end = 0;
 
+    // The current amount of memory mapped via MapPhysicalMemory.
+    // This is used here (and in Nintendo's kernel) only for debugging, and does not impact
+    // any behavior.
+    u64 physical_memory_mapped = 0;
+
     Core::System& system;
 };
 } // namespace Kernel