virtio-devices, vmm: Deprecate "GuestMemory::with_regions(_mut)"

Function "GuestMemory::with_regions(_mut)" were mainly temporary methods
to access the regions in `GuestMemory` as the lack of iterator-based
access, and hence they are deprecated in the upstream vm-memory crate [1].

[1] rust-vmm/vm-memory#133

Signed-off-by: Bo Chen <chen.bo@intel.com>

virtio-devices/src/vhost_user/vu_common_ctrl.rs

@@ -24,10 +24,10 @@ pub struct VhostUserConfig {
 
 pub fn update_mem_table(vu: &mut Master, mem: &GuestMemoryMmap) -> Result<()> {
     let mut regions: Vec<VhostUserMemoryRegionInfo> = Vec::new();
-    mem.with_regions_mut(|_, region| {
+    for region in mem.iter() {
         let (mmap_handle, mmap_offset) = match region.file_offset() {
             Some(_file_offset) => (_file_offset.file().as_raw_fd(), _file_offset.start()),
-            None => return Err(MmapError::NoMemoryRegion),
+            None => return Err(Error::VhostUserMemoryRegion(MmapError::NoMemoryRegion)),
         };
 
         let vhost_user_net_reg = VhostUserMemoryRegionInfo {
@@ -39,10 +39,7 @@ pub fn update_mem_table(vu: &mut Master, mem: &GuestMemoryMmap) -> Result<()> {
         };
 
         regions.push(vhost_user_net_reg);
-
-        Ok(())
-    })
-    .map_err(Error::VhostUserMemoryRegion)?;
+    }
 
     vu.set_mem_table(regions.as_slice())
         .map_err(Error::VhostUserSetMemTable)?;

vmm/src/memory_manager.rs

@@ -773,7 +773,7 @@ impl MemoryManager {
             log_dirty,
         }));
 
-        guest_memory.memory().with_regions(|_, region| {
+        for region in guest_memory.memory().iter() {
             let mut mm = memory_manager.lock().unwrap();
             let slot = mm.create_userspace_mapping(
                 region.start_addr().raw_value(),
@@ -788,9 +788,7 @@ impl MemoryManager {
                 size: region.len(),
                 slot,
             });
-
-            Ok(())
-        })?;
+        }
 
         for region in virtio_mem_regions.drain(..) {
             let mut mm = memory_manager.lock().unwrap();
@@ -1942,7 +1940,7 @@ impl Snapshottable for MemoryManager {
 
         let mut memory_regions: Vec<MemoryRegion> = Vec::new();
 
-        guest_memory.with_regions_mut(|index, region| {
+        for (index, region) in guest_memory.iter().enumerate() {
             if region.len() == 0 {
                 return Err(MigratableError::Snapshot(anyhow!("Zero length region")));
             }
@@ -1970,9 +1968,7 @@ impl Snapshottable for MemoryManager {
                 start_addr: region.start_addr().0,
                 size: region.len(),
             });
-
-            Ok(())
-        })?;
+        }
 
         // Store locally this list of regions as it will be used through the
         // Transportable::send() implementation. The point is to avoid the

vmm/src/vm.rs

@@ -1989,13 +1989,12 @@ impl Vm {
         let mut table = MemoryRangeTable::default();
         let guest_memory = self.memory_manager.lock().as_ref().unwrap().guest_memory();
 
-        guest_memory.memory().with_regions_mut(|_, region| {
+        for region in guest_memory.memory().iter() {
             table.push(MemoryRange {
                 gpa: region.start_addr().raw_value(),
                 length: region.len() as u64,
             });
-            Ok(())
-        })?;
+        }
 
         Ok(table)
     }
@@ -2490,7 +2489,7 @@ pub fn test_vm() {
     let hv = hypervisor::new().unwrap();
     let vm = hv.create_vm().expect("new VM creation failed");
 
-    mem.with_regions(|index, region| {
+    for (index, region) in mem.iter().enumerate() {
         let mem_region = vm.make_user_memory_region(
             index as u32,
             region.start_addr().raw_value(),
@@ -2501,8 +2500,8 @@ pub fn test_vm() {
         );
 
         vm.set_user_memory_region(mem_region)
-    })
-    .expect("Cannot configure guest memory");
+            .expect("Cannot configure guest memory");
+    }
     mem.write_slice(&code, load_addr)
         .expect("Writing code to memory failed");