diff --git a/src/dynarmic/backend/x64/a64_emit_x64.cpp b/src/dynarmic/backend/x64/a64_emit_x64.cpp
index d591b716..6690e68e 100644
--- a/src/dynarmic/backend/x64/a64_emit_x64.cpp
+++ b/src/dynarmic/backend/x64/a64_emit_x64.cpp
@@ -881,11 +881,11 @@ Xbyak::RegExp EmitVAddrLookup(BlockOfCode& code, A64EmitContext& ctx, size_t bit
 }
 
 Xbyak::RegExp EmitFastmemVAddr(BlockOfCode& code, A64EmitContext& ctx, Xbyak::Label& abort, Xbyak::Reg64 vaddr, bool& require_abort_handling) {
-    const size_t unused_top_bits = 64 - ctx.conf.page_table_address_space_bits;
+    const size_t unused_top_bits = 64 - ctx.conf.fastmem_address_space_bits;
 
     if (unused_top_bits == 0) {
         return r13 + vaddr;
-    } else if (ctx.conf.silently_mirror_page_table) {
+    } else if (ctx.conf.silently_mirror_fastmem) {
         Xbyak::Reg64 tmp = ctx.reg_alloc.ScratchGpr();
         if (unused_top_bits < 32) {
             code.mov(tmp, vaddr);
@@ -895,19 +895,19 @@ Xbyak::RegExp EmitFastmemVAddr(BlockOfCode& code, A64EmitContext& ctx, Xbyak::La
             code.mov(tmp.cvt32(), vaddr.cvt32());
         } else {
             code.mov(tmp.cvt32(), vaddr.cvt32());
-            code.and_(tmp, u32((1 << ctx.conf.page_table_address_space_bits) - 1));
+            code.and_(tmp, u32((1 << ctx.conf.fastmem_address_space_bits) - 1));
         }
         return r13 + tmp;
     } else {
-        if (ctx.conf.page_table_address_space_bits < 32) {
-            code.test(vaddr, u32(-(1 << ctx.conf.page_table_address_space_bits)));
+        if (ctx.conf.fastmem_address_space_bits < 32) {
+            code.test(vaddr, u32(-(1 << ctx.conf.fastmem_address_space_bits)));
             code.jnz(abort, code.T_NEAR);
             require_abort_handling = true;
         } else {
             // TODO: Consider having TEST as above but coalesce 64-bit constant in register allocator
             Xbyak::Reg64 tmp = ctx.reg_alloc.ScratchGpr();
             code.mov(tmp, vaddr);
-            code.shr(tmp, int(ctx.conf.page_table_address_space_bits));
+            code.shr(tmp, int(ctx.conf.fastmem_address_space_bits));
             code.jnz(abort, code.T_NEAR);
             require_abort_handling = true;
         }
diff --git a/src/dynarmic/interface/A64/config.h b/src/dynarmic/interface/A64/config.h
index baa08577..1d4a758c 100644
--- a/src/dynarmic/interface/A64/config.h
+++ b/src/dynarmic/interface/A64/config.h
@@ -202,7 +202,7 @@ struct UserConfig {
     void** page_table = nullptr;
     /// Declares how many valid address bits are there in virtual addresses.
     /// Determines the size of page_table. Valid values are between 12 and 64 inclusive.
-    /// This is only used if page_table or fastmem_pointer is not nullptr.
+    /// This is only used if page_table is not nullptr.
     size_t page_table_address_space_bits = 36;
     /// Masks out the first N bits in host pointers from the page table.
     /// The intention behind this is to allow users of Dynarmic to pack attributes in the
@@ -213,7 +213,7 @@ struct UserConfig {
     /// page table. If true, Dynarmic will silently mirror page_table's address space. If
     /// false, accessing memory outside of page_table bounds will result in a call to the
     /// relevant memory callback.
-    /// This is only used if page_table or fastmem_pointer is not nullptr.
+    /// This is only used if page_table is not nullptr.
     bool silently_mirror_page_table = true;
     /// Determines if the pointer in the page_table shall be offseted locally or globally.
     /// 'false' will access page_table[addr >> bits][addr & mask]
@@ -243,6 +243,16 @@ struct UserConfig {
     /// Recompiled code will use the page_table if this is available, otherwise memory
     /// accesses will hit the memory callbacks.
     bool recompile_on_fastmem_failure = true;
+    /// Declares how many valid address bits are there in virtual addresses.
+    /// Determines the size of fastmem arena. Valid values are between 12 and 64 inclusive.
+    /// This is only used if fastmem_pointer is not nullptr.
+    size_t fastmem_address_space_bits = 36;
+    /// Determines what happens if the guest accesses an entry that is off the end of the
+    /// fastmem arena. If true, Dynarmic will silently mirror fastmem's address space. If
+    /// false, accessing memory outside of fastmem bounds will result in a call to the
+    /// relevant memory callback.
+    /// This is only used if fastmem_pointer is not nullptr.
+    bool silently_mirror_fastmem = true;
 
     /// This option relates to translation. Generally when we run into an unpredictable
     /// instruction the ExceptionRaised callback is called. If this is true, we define
diff --git a/tests/A64/a64.cpp b/tests/A64/a64.cpp
index 84c74a99..6a465cfa 100644
--- a/tests/A64/a64.cpp
+++ b/tests/A64/a64.cpp
@@ -852,9 +852,9 @@ TEST_CASE("A64: Memory access (fastmem)", "[a64]") {
     A64FastmemTestEnv env{backing_memory};
     Dynarmic::A64::UserConfig config{&env};
     config.fastmem_pointer = backing_memory;
-    config.page_table_address_space_bits = address_width;
+    config.fastmem_address_space_bits = address_width;
     config.recompile_on_fastmem_failure = false;
-    config.silently_mirror_page_table = true;
+    config.silently_mirror_fastmem = true;
     config.processor_id = 0;
 
     Dynarmic::A64::Jit jit{config};