Derive Debug for SharedMemory.

This is useful when adding temporary logs to dump it for debugging.

TEST=tools/dev_container tools/run_tests --target=vm:aarch64

Change-Id: Ia982104943b214b67472f7bdd03c9511191c35cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3627452
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Dmitry Torokhov <dtor@chromium.org>
Auto-Submit: Andrew Walbran <qwandor@google.com>
Reviewed-by: Dmitry Torokhov <dtor@chromium.org>

base/src/shm.rs

@@ -13,7 +13,7 @@ use serde::{Deserialize, Serialize};
 
 /// See [SharedMemory](crate::platform::SharedMemory) for struct- and method-level
 /// documentation.
-#[derive(Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize)]
 #[serde(transparent)]
 pub struct SharedMemory(pub(crate) SysUtilSharedMemory);
 impl SharedMemory {

base/src/sys/unix/shm.rs

@@ -23,7 +23,7 @@ use crate::SharedMemory as CrateSharedMemory;
 use crate::{AsRawDescriptor, IntoRawDescriptor, RawDescriptor, SafeDescriptor};
 
 /// A shared memory file descriptor and its size.
-#[derive(Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize)]
 pub struct SharedMemory {
     #[serde(with = "super::with_as_descriptor")]
     fd: File,

vm_memory/src/guest_memory.rs

@@ -68,7 +68,7 @@ bitflags! {
 }
 
 /// A file-like object backing `MemoryRegion`.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub enum BackingObject {
     Shm(Arc<SharedMemory>),
     File(Arc<File>),
@@ -95,6 +95,7 @@ impl AsRef<dyn AsRawDescriptor + Sync + Send> for BackingObject {
 /// A regions of memory mapped memory.
 /// Holds the memory mapping with its offset in guest memory.
 /// Also holds the backing object for the mapping and the offset in that object of the mapping.
+#[derive(Debug)]
 pub struct MemoryRegion {
     mapping: MemoryMapping,
     guest_base: GuestAddress,
@@ -162,7 +163,7 @@ impl MemoryRegion {
 
 /// Tracks memory regions and where they are mapped in the guest, along with shm
 /// fds of the underlying memory regions.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct GuestMemory {
     regions: Arc<[MemoryRegion]>,
 }