vmm, hypervisor: introduce and use make_user_memory_region

This removes the last KVM-ism from memory_manager. Also make use of that
method in other places.

Signed-off-by: Wei Liu <liuwe@microsoft.com>

hypervisor/src/kvm/mod.rs

@@ -172,6 +172,25 @@ impl vm::Vm for KvmVm {
             .map_err(|e| vm::HypervisorVmError::SetGsiRouting(e.into()))
     }
     ///
+    /// Creates a memory region structure that can be used with set_user_memory_region
+    ///
+    fn make_user_memory_region(
+        &self,
+        slot: u32,
+        guest_phys_addr: u64,
+        memory_size: u64,
+        userspace_addr: u64,
+        readonly: bool,
+    ) -> MemoryRegion {
+        MemoryRegion {
+            slot,
+            guest_phys_addr,
+            memory_size,
+            userspace_addr,
+            flags: if readonly { KVM_MEM_READONLY } else { 0 },
+        }
+    }
+    ///
     /// Creates/modifies a guest physical memory slot.
     ///
     fn set_user_memory_region(&self, user_memory_region: MemoryRegion) -> vm::Result<()> {

hypervisor/src/vm.rs

@@ -143,6 +143,15 @@ pub trait Vm: Send + Sync {
     fn unregister_ioevent(&self, fd: &EventFd, addr: &IoEventAddress) -> Result<()>;
     /// Sets the GSI routing table entries, overwriting any previously set
     fn set_gsi_routing(&self, irq_routing: &IrqRouting) -> Result<()>;
+    /// Creates a memory region structure that can be used with set_user_memory_region
+    fn make_user_memory_region(
+        &self,
+        slot: u32,
+        guest_phys_addr: u64,
+        memory_size: u64,
+        userspace_addr: u64,
+        readonly: bool,
+    ) -> MemoryRegion;
     /// Creates/modifies a guest physical memory slot.
     fn set_user_memory_region(&self, user_memory_region: MemoryRegion) -> Result<()>;
     /// Creates an emulated device in the kernel.

vmm/src/device_manager.rs

@@ -588,13 +588,13 @@ impl DeviceRelocation for AddressManager {
                 if let Some(mut shm_regions) = virtio_dev.get_shm_regions() {
                     if shm_regions.addr.raw_value() == old_base {
                         // Remove old region from KVM by passing a size of 0.
-                        let mut mem_region = hypervisor::MemoryRegion {
+                        let mut mem_region = self.vm.make_user_memory_region(
-                            slot: shm_regions.mem_slot,
+                            shm_regions.mem_slot,
-                            guest_phys_addr: old_base,
+                            old_base,
-                            memory_size: 0,
+                            0,
-                            userspace_addr: shm_regions.host_addr,
+                            shm_regions.host_addr,
-                            flags: 0,
+                            false,
-                        };
+                        );
 
                         self.vm.set_user_memory_region(mem_region).map_err(|e| {
                             io::Error::new(

vmm/src/memory_manager.rs

@@ -676,17 +676,13 @@ impl MemoryManager {
         readonly: bool,
     ) -> Result<u32, Error> {
         let slot = self.allocate_memory_slot();
-        let mem_region = hypervisor::MemoryRegion {
+        let mem_region = self.vm.make_user_memory_region(
             slot,
             guest_phys_addr,
             memory_size,
             userspace_addr,
-            flags: if readonly {
+            readonly,
-                hypervisor::kvm::KVM_MEM_READONLY
+        );
-            } else {
-                0
-            },
-        };
 
         self.vm
             .set_user_memory_region(mem_region)
@@ -733,13 +729,13 @@ impl MemoryManager {
         mergeable: bool,
         slot: u32,
     ) -> Result<(), Error> {
-        let mem_region = hypervisor::MemoryRegion {
+        let mem_region = self.vm.make_user_memory_region(
             slot,
             guest_phys_addr,
-            memory_size: 0,
+            0, /* memory_size -- using 0 removes this slot */
             userspace_addr,
-            flags: 0,
+            false, /* readonly -- don't care */
-        };
+        );
 
         self.vm
             .set_user_memory_region(mem_region)

vmm/src/vm.rs

@@ -1451,13 +1451,13 @@ pub fn test_vm() {
     let vm = hv.create_vm().expect("new VM creation failed");
 
     mem.with_regions(|index, region| {
-        let mem_region = hypervisor::MemoryRegion {
+        let mem_region = vm.make_user_memory_region(
-            slot: index as u32,
+            index as u32,
-            guest_phys_addr: region.start_addr().raw_value(),
+            region.start_addr().raw_value(),
-            memory_size: region.len() as u64,
+            region.len() as u64,
-            userspace_addr: region.as_ptr() as u64,
+            region.as_ptr() as u64,
-            flags: 0,
+            false,
-        };
+        );
 
         vm.set_user_memory_region(mem_region)
     })