vmm: save guest memory for coredump

Guest memory is needed for analysis in crash tool, so save it
for coredump.

Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Co-authored-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vmm/src/memory_manager.rs

@@ -8,7 +8,7 @@ use crate::config::{HotplugMethod, MemoryConfig, MemoryZoneConfig};
 #[cfg(feature = "guest_debug")]
 use crate::coredump::{CoredumpMemoryRegion, CoredumpMemoryRegions};
 #[cfg(feature = "guest_debug")]
-use crate::coredump::{DumpState, GuestDebuggable, GuestDebuggableError};
+use crate::coredump::{DumpState, GuestDebuggableError};
 use crate::migration::url_to_path;
 use crate::MEMORY_MANAGER_SNAPSHOT_ID;
 use crate::{GuestMemoryMmap, GuestRegionMmap};
@@ -1877,6 +1877,47 @@ impl MemoryManager {
 
         CoredumpMemoryRegions { ram_maps }
     }
+
+    #[cfg(feature = "guest_debug")]
+    pub fn coredump_iterate_save_mem(
+        &mut self,
+        dump_state: &DumpState,
+    ) -> std::result::Result<(), GuestDebuggableError> {
+        let snapshot_memory_ranges = self
+            .memory_range_table(false)
+            .map_err(|e| GuestDebuggableError::Coredump(e.into()))?;
+
+        if snapshot_memory_ranges.is_empty() {
+            return Ok(());
+        }
+
+        let mut coredump_file = dump_state.file.as_ref().unwrap();
+
+        let guest_memory = self.guest_memory.memory();
+        let mut total_bytes: u64 = 0;
+
+        for range in snapshot_memory_ranges.regions() {
+            let mut offset: u64 = 0;
+            loop {
+                let bytes_written = guest_memory
+                    .write_to(
+                        GuestAddress(range.gpa + offset),
+                        &mut coredump_file,
+                        (range.length - offset) as usize,
+                    )
+                    .map_err(|e| GuestDebuggableError::Coredump(e.into()))?;
+                offset += bytes_written as u64;
+                total_bytes += bytes_written as u64;
+
+                if offset == range.length {
+                    break;
+                }
+            }
+        }
+
+        debug!("coredump total bytes {}", total_bytes);
+        Ok(())
+    }
 }
 
 struct MemoryNotify {

vmm/src/vm.rs

@@ -3052,7 +3052,10 @@ impl GuestDebuggable for Vm {
         self.write_note(&coredump_state)?;
         self.write_loads(&coredump_state)?;
 
-        Ok(())
+        self.memory_manager
+            .lock()
+            .unwrap()
+            .coredump_iterate_save_mem(&coredump_state)
     }
 }