From 04c8d5208b92904b08321944c8b4a39bf9d5f529 Mon Sep 17 00:00:00 2001
From: Andrea Fioraldi <andreafioraldi@gmail.com>
Date: Fri, 25 Aug 2023 11:42:23 +0200
Subject: [PATCH] qemu: Fix cpu page size function for full-system (#1452)

* Revert "qemu: add cpu page_size call (#1433)"

This reverts commit d338b30c080ecfe1a6639185b6505b7a7b8edbeb.

* Reintroduce page_size
---
 libafl_qemu/libafl_qemu_build/src/bindings.rs       |  2 +-
 .../libafl_qemu_sys/src/x86_64_stub_bindings.rs     | 11 +++++------
 libafl_qemu/src/emu.rs                              | 13 ++++++-------
 3 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/libafl_qemu/libafl_qemu_build/src/bindings.rs b/libafl_qemu/libafl_qemu_build/src/bindings.rs
index a2c9ed2567..37b339197a 100644
--- a/libafl_qemu/libafl_qemu_build/src/bindings.rs
+++ b/libafl_qemu/libafl_qemu_build/src/bindings.rs
@@ -115,12 +115,12 @@ pub fn generate(
         .allowlist_function("tlb_plugin_lookup")
         .allowlist_function("qemu_plugin_hwaddr_phys_addr")
         .allowlist_function("qemu_plugin_get_hwaddr")
+        .allowlist_function("qemu_target_page_size")
         .allowlist_function("syx_snapshot_init")
         .allowlist_function("syx_snapshot_create")
         .allowlist_function("syx_snapshot_root_restore")
         .allowlist_function("syx_snapshot_dirty_list_add")
         .allowlist_function("device_list_all")
-        .allowlist_function("qemu_target_page_size")
         .blocklist_function("main_loop_wait") // bindgen issue #1313
         .parse_callbacks(Box::new(bindgen::CargoCallbacks));
 
diff --git a/libafl_qemu/libafl_qemu_sys/src/x86_64_stub_bindings.rs b/libafl_qemu/libafl_qemu_sys/src/x86_64_stub_bindings.rs
index 95e9e177c5..b780f74d35 100644
--- a/libafl_qemu/libafl_qemu_sys/src/x86_64_stub_bindings.rs
+++ b/libafl_qemu/libafl_qemu_sys/src/x86_64_stub_bindings.rs
@@ -1,5 +1,10 @@
 /* automatically generated by rust-bindgen 0.66.1 */
 
+extern "C" {
+    #[doc = " qemu_target_page_size - return the target's page size"]
+    pub fn qemu_target_page_size() -> usize;
+}
+
 #[repr(C)]
 #[derive(Copy, Clone, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
 pub struct __BindgenBitfieldUnit<Storage> {
@@ -11100,12 +11105,6 @@ impl ::std::ops::BitAndAssign for qemu_plugin_mem_rw {
         self.0 &= rhs.0;
     }
 }
-
-extern "C" {
-    #[doc = " qemu_target_page_size - return the target's page size"]
-    pub fn qemu_target_page_size() -> usize;
-}
-
 #[repr(transparent)]
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct qemu_plugin_mem_rw(pub ::std::os::raw::c_uint);
diff --git a/libafl_qemu/src/emu.rs b/libafl_qemu/src/emu.rs
index 14074c3516..21ed930630 100644
--- a/libafl_qemu/src/emu.rs
+++ b/libafl_qemu/src/emu.rs
@@ -14,10 +14,6 @@ use std::{
     ptr::null_mut,
 };
 
-thread_local! {
-    static SNAPSHOT_PAGE_SIZE: OnceCell<usize> = OnceCell::new();
-}
-
 #[cfg(emulation_mode = "usermode")]
 use libc::c_int;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
@@ -751,7 +747,11 @@ impl CPU {
     pub fn page_size(&self) -> usize {
         #[cfg(emulation_mode = "usermode")]
         {
-            SNAPSHOT_PAGE_SIZE.with(|s| {
+            thread_local! {
+                static PAGE_SIZE: OnceCell<usize> = OnceCell::new();
+            }
+
+            PAGE_SIZE.with(|s| {
                 *s.get_or_init(|| {
                     unsafe { libc::sysconf(libc::_SC_PAGE_SIZE) }
                         .try_into()
@@ -761,8 +761,7 @@ impl CPU {
         }
         #[cfg(emulation_mode = "systemmode")]
         {
-            SNAPSHOT_PAGE_SIZE
-                .with(|s| *s.get_or_init(|| unsafe { libafl_qemu_sys::qemu_target_page_size() }))
+            unsafe { libafl_qemu_sys::qemu_target_page_size() }
         }
     }
 }