[nce] Added case for access fault handling to manage page edge cases

src/core/arm/nce/arm_nce.cpp

@@ -43,6 +43,7 @@ fpsimd_context* GetFloatingPointState(mcontext_t& host_ctx) {
 
 using namespace Common::Literals;
 constexpr u32 StackSize = 128_KiB;
+constexpr u64 SplitPageAccessWindow = 64;
 
 } // namespace
 
@@ -158,18 +159,33 @@ bool ArmNce::HandleGuestAlignmentFault(GuestContext* guest_ctx, void* raw_info,
 }
 
 bool ArmNce::HandleGuestAccessFault(GuestContext* guest_ctx, void* raw_info, void* raw_context) {
+    auto& host_ctx = static_cast<ucontext_t*>(raw_context)->uc_mcontext;
+    auto* fpctx = GetFloatingPointState(host_ctx);
     auto* info = static_cast<siginfo_t*>(raw_info);
 
-    // Try to handle an invalid access.
-    // TODO: handle accesses which split a page?
-    const Common::ProcessAddress addr =
-        (reinterpret_cast<u64>(info->si_addr) & ~Memory::YUZU_PAGEMASK);
+    const u64 fault_addr = reinterpret_cast<u64>(info->si_addr);
+    const Common::ProcessAddress addr = fault_addr & ~Memory::YUZU_PAGEMASK;
+    const u64 page_offset = fault_addr & Memory::YUZU_PAGEMASK;
     auto& memory = guest_ctx->parent->m_running_thread->GetOwnerProcess()->GetMemory();
-    if (memory.InvalidateNCE(addr, Memory::YUZU_PAGESIZE)) {
+    bool handled = memory.InvalidateNCE(addr, Memory::YUZU_PAGESIZE);
+
+    if (page_offset < SplitPageAccessWindow && addr >= Memory::YUZU_PAGESIZE) {
+        handled |= memory.InvalidateNCE(addr - Memory::YUZU_PAGESIZE, Memory::YUZU_PAGESIZE);
+    }
+    if (page_offset + SplitPageAccessWindow > Memory::YUZU_PAGESIZE) {
+        handled |= memory.InvalidateNCE(addr + Memory::YUZU_PAGESIZE, Memory::YUZU_PAGESIZE);
+    }
+
+    if (handled) {
         // We handled the access successfully and are returning to guest code.
         return true;
     }
 
+    if (auto next_pc = MatchAndExecuteOneInstruction(memory, &host_ctx, fpctx); next_pc) {
+        host_ctx.pc = *next_pc;
+        return true;
+    }
+
     // We couldn't handle the access.
     return HandleFailedGuestFault(guest_ctx, raw_info, raw_context);
 }