- WritableRegion: enable wrapping IMemoryOwner<byte>

- IVirtualMemoryManager impls of GetWritableRegion() use pooled memory when region is non-contiguous.
- IVirtualMemoryManager: add GetReadOnlySequence() and impls
- ByteMemoryPool: add new method RentCopy()
- ByteMemoryPool: make class static, remove ctor and singleton field from earlier impl

src/Ryujinx.Common/Memory/ByteMemoryPool.cs

@@ -78,6 +78,20 @@ namespace Ryujinx.Common.Memory
 
             return buffer;
         }
+        
+        /// <summary>
+        /// Copies <paramref name="buffer"/> into a newly rented byte memory buffer.
+        /// </summary>
+        /// <param name="buffer">The byte buffer to copy</param>
+        /// <returns>A <see cref="IMemoryOwner{Byte}"/> wrapping the rented memory with <paramref name="buffer"/> copied to it</returns>
+        public static IMemoryOwner<byte> RentCopy(ReadOnlySpan<byte> buffer)
+        {
+            var copy = RentImpl(buffer.Length);
+
+            buffer.CopyTo(copy.Memory.Span);
+
+            return copy;
+        }
 
         /// <summary>
         /// Copies <paramref name="buffer"/> into a newly rented byte memory buffer.

src/Ryujinx.Common/Memory/BytesReadOnlySequenceSegment.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Buffers;
+
+namespace Ryujinx.Common.Memory
+{
+    /// <summary>
+    /// A concrete implementation of <seealso cref="ReadOnlySequence{T}"/>,
+    /// with methods to help build a full sequence.
+    /// </summary>
+    public sealed class BytesReadOnlySequenceSegment : ReadOnlySequenceSegment<byte>
+    {
+        public BytesReadOnlySequenceSegment(Memory<byte> memory) => Memory = memory;
+
+        public BytesReadOnlySequenceSegment Append(Memory<byte> memory)
+        {
+            var nextSegment = new BytesReadOnlySequenceSegment(memory)
+            {
+                RunningIndex = RunningIndex + Memory.Length
+            };
+
+            Next = nextSegment;
+
+            return nextSegment;
+        }
+    }
+}

src/Ryujinx.Memory/IVirtualMemoryManager.cs

@@ -123,6 +123,16 @@ namespace Ryujinx.Memory
                 writableRegion.Memory.Span.Fill(value);
             }
         }
+        
+        /// <summary>
+        /// Gets a read-only sequence of read-only memory blocks from CPU mapped memory.
+        /// </summary>
+        /// <param name="va">Virtual address of the data</param>
+        /// <param name="size">Size of the data</param>
+        /// <param name="tracked">True if read tracking is triggered on the memory</param>
+        /// <returns>A read-only sequence of read-only memory of the data</returns>
+        /// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
+        ReadOnlySequence<byte> GetReadOnlySequence(ulong va, int size, bool tracked = false);
 
         /// <summary>
         /// Gets a read-only sequence of read-only memory blocks from CPU mapped memory.