commit 8ec05d17a90d359412fc0a011c93d9ba4d7d0269
author Treehugger Robot <android-test-infra-autosubmit@system.gserviceaccount.com> Wed May 03 05:56:32 2023 +0000
committer Gerrit Code Review <noreply-gerritcodereview@google.com> Wed May 03 05:56:32 2023 +0000
tree 5c49de82f66b457c835478e55bf3d79112a5fb3e
parent a4cce67e9af7a92603acb0f224476d3af5d2ceaa
parent 0dcc75e67a019b491b3447e54dcc6931b79de714

Merge changes Ie31f6c6f,I56678bd0,Ic6e651a7

* changes:
  libs: libfdt: Fix Fdt::header() using bad pointer
  pvmfw: Remove unnecessary flush of the guest DT
  pvmfw: apply_debug_policy: Backup DT before unpacking

libs/libfdt/src/lib.rs

diff --git a/libs/libfdt/src/lib.rs b/libs/libfdt/src/lib.rs
index 61b69f5..9785941 100644
--- a/libs/libfdt/src/lib.rs
+++ b/libs/libfdt/src/lib.rs
@@ -780,11 +780,11 @@
 
     /// Return a shared pointer to the device tree.
     pub fn as_ptr(&self) -> *const c_void {
-        self as *const _ as *const c_void
+        self.buffer.as_ptr().cast::<_>()
     }
 
     fn as_mut_ptr(&mut self) -> *mut c_void {
-        self as *mut _ as *mut c_void
+        self.buffer.as_mut_ptr().cast::<_>()
     }
 
     fn capacity(&self) -> usize {
@@ -792,8 +792,9 @@
     }
 
     fn header(&self) -> &libfdt_bindgen::fdt_header {
+        let p = self.as_ptr().cast::<_>();
         // SAFETY - A valid FDT (verified by constructor) must contain a valid fdt_header.
-        unsafe { &*(&self as *const _ as *const libfdt_bindgen::fdt_header) }
+        unsafe { &*p }
     }
 
     fn totalsize(&self) -> usize {

pvmfw/src/entry.rs

diff --git a/pvmfw/src/entry.rs b/pvmfw/src/entry.rs
index 3897c1f..999baee 100644
--- a/pvmfw/src/entry.rs
+++ b/pvmfw/src/entry.rs
@@ -255,7 +255,6 @@
     )?;
 
     helpers::flushed_zeroize(bcc_slice);
-    helpers::flush(slices.fdt.as_slice());
 
     info!("Expecting a bug making MMIO_GUARD_UNMAP return NOT_SUPPORTED on success");
     MEMORY.lock().as_mut().unwrap().mmio_unmap_all().map_err(|e| {

pvmfw/src/fdt.rs

diff --git a/pvmfw/src/fdt.rs b/pvmfw/src/fdt.rs
index 4c1362d..5ecb038 100644
--- a/pvmfw/src/fdt.rs
+++ b/pvmfw/src/fdt.rs
@@ -722,21 +722,26 @@
     debug_policy: Option<&mut [u8]>,
     debuggable: bool,
 ) -> libfdt::Result<()> {
-    fdt.unpack()?;
+    if let Some(debug_policy) = debug_policy {
+        let backup = Vec::from(fdt.as_slice());
+        fdt.unpack()?;
+        let backup_fdt = Fdt::from_slice(backup.as_slice()).unwrap();
+        if apply_debug_policy(fdt, backup_fdt, debug_policy)? {
+            info!("Debug policy applied.");
+        } else {
+            // apply_debug_policy restored fdt to backup_fdt so unpack it again.
+            fdt.unpack()?;
+        }
+    } else {
+        info!("No debug policy found.");
+        fdt.unpack()?;
+    }
 
     patch_dice_node(fdt, bcc.as_ptr() as usize, bcc.len())?;
 
     set_or_clear_chosen_flag(fdt, cstr!("avf,strict-boot"), strict_boot)?;
     set_or_clear_chosen_flag(fdt, cstr!("avf,new-instance"), new_instance)?;
 
-    if let Some(debug_policy) = debug_policy {
-        if apply_debug_policy(fdt, debug_policy)? {
-            info!("Debug policy applied.");
-        }
-    } else {
-        info!("No debug policy found.");
-    }
-
     if debuggable {
         if let Some(bootargs) = read_bootargs_from(fdt)? {
             filter_out_dangerous_bootargs(fdt, &bootargs)?;
@@ -779,9 +784,11 @@
 /// Apply the debug policy overlay to the guest DT.
 ///
 /// Returns Ok(true) on success, Ok(false) on recovered failure and Err(_) on corruption of the DT.
-fn apply_debug_policy(fdt: &mut Fdt, debug_policy: &[u8]) -> libfdt::Result<bool> {
-    let backup_fdt = Vec::from(fdt.as_slice());
-
+fn apply_debug_policy(
+    fdt: &mut Fdt,
+    backup_fdt: &Fdt,
+    debug_policy: &[u8],
+) -> libfdt::Result<bool> {
     let mut debug_policy = Vec::from(debug_policy);
     let overlay = match Fdt::from_mut_slice(debug_policy.as_mut_slice()) {
         Ok(overlay) => overlay,