refactor: rename struct Bounce to MaybeBounce

It has a boolean inside of it that determines whether we actually
bounce, so rename it to reflect that.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

src/vmm/src/builder.rs

@@ -65,7 +65,7 @@ use crate::vmm_config::instance_info::InstanceInfo;
 use crate::vmm_config::machine_config::MachineConfigError;
 use crate::vmm_config::snapshot::{MemBackendConfig, MemBackendType};
 use crate::vstate::kvm::Kvm;
-use crate::vstate::memory::Bounce;
+use crate::vstate::memory::MaybeBounce;
 use crate::vstate::vcpu::{Vcpu, VcpuError};
 use crate::vstate::vm::{KVM_GMEM_NO_DIRECT_MAP, Vm};
 use crate::{EventManager, Vmm, VmmError, device_manager};
@@ -274,7 +274,7 @@ pub fn build_microvm_for_boot(
     }
 
     let entry_point = load_kernel(
-        Bounce(&boot_config.kernel_file, secret_free),
+        MaybeBounce(&boot_config.kernel_file, secret_free),
         vmm.vm.guest_memory(),
     )?;
     let initrd = match &boot_config.initrd_file {
@@ -286,7 +286,7 @@ pub fn build_microvm_for_boot(
 
             Some(InitrdConfig::from_reader(
                 vmm.vm.guest_memory(),
-                Bounce(initrd_file, secret_free),
+                MaybeBounce(initrd_file, secret_free),
                 u64_to_usize(size),
             )?)
         }

src/vmm/src/vstate/memory.rs

@@ -64,10 +64,10 @@ pub enum MemoryError {
 /// `Write` respectively, by reading/writing using a bounce buffer, and memcpy-ing into the
 /// [`VolatileSlice`].
 #[derive(Debug)]
-pub struct Bounce<T>(pub T, pub bool);
+pub struct MaybeBounce<T>(pub T, pub bool);
 
 // FIXME: replace AsFd with ReadVolatile once &File: ReadVolatile in vm-memory.
-impl<T: Read + AsFd> ReadVolatile for Bounce<T> {
+impl<T: Read + AsFd> ReadVolatile for MaybeBounce<T> {
     fn read_volatile<B: BitmapSlice>(
         &mut self,
         buf: &mut VolatileSlice<B>,
@@ -86,7 +86,7 @@ impl<T: Read + AsFd> ReadVolatile for Bounce<T> {
     }
 }
 
-impl<T: Write + AsFd> WriteVolatile for Bounce<T> {
+impl<T: Write + AsFd> WriteVolatile for MaybeBounce<T> {
     fn write_volatile<B: BitmapSlice>(
         &mut self,
         buf: &VolatileSlice<B>,
@@ -103,13 +103,13 @@ impl<T: Write + AsFd> WriteVolatile for Bounce<T> {
     }
 }
 
-impl<R: Read> Read for Bounce<R> {
+impl<R: Read> Read for MaybeBounce<R> {
     fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
         self.0.read(buf)
     }
 }
 
-impl<S: Seek> Seek for Bounce<S> {
+impl<S: Seek> Seek for MaybeBounce<S> {
     fn seek(&mut self, pos: SeekFrom) -> std::io::Result<u64> {
         self.0.seek(pos)
     }
@@ -950,10 +950,10 @@ mod tests {
 
         let mut data = (0..=255).collect_vec();
 
-        Bounce(file_direct.as_file(), false)
+        MaybeBounce(file_direct.as_file(), false)
             .write_all_volatile(&VolatileSlice::from(data.as_mut_slice()))
             .unwrap();
-        Bounce(file_bounced.as_file(), true)
+        MaybeBounce(file_bounced.as_file(), true)
             .write_all_volatile(&VolatileSlice::from(data.as_mut_slice()))
             .unwrap();
 
@@ -963,10 +963,10 @@ mod tests {
         file_direct.as_file().seek(SeekFrom::Start(0)).unwrap();
         file_bounced.as_file().seek(SeekFrom::Start(0)).unwrap();
 
-        Bounce(file_direct.as_file(), false)
+        MaybeBounce(file_direct.as_file(), false)
             .read_exact_volatile(&mut VolatileSlice::from(data_direct.as_mut_slice()))
             .unwrap();
-        Bounce(file_bounced.as_file(), true)
+        MaybeBounce(file_bounced.as_file(), true)
             .read_exact_volatile(&mut VolatileSlice::from(data_bounced.as_mut_slice()))
             .unwrap();
 

src/vmm/src/vstate/vm.rs

@@ -27,8 +27,8 @@ use crate::persist::{CreateSnapshotError, GuestRegionUffdMapping};
 use crate::utils::u64_to_usize;
 use crate::vmm_config::snapshot::SnapshotType;
 use crate::vstate::memory::{
-    Bounce, GuestMemory, GuestMemoryExtension, GuestMemoryMmap, GuestMemoryRegion, GuestRegionMmap,
-    KvmRegion,
+    GuestMemory, GuestMemoryExtension, GuestMemoryMmap, GuestMemoryRegion, GuestRegionMmap,
+    KvmRegion, MaybeBounce,
 };
 use crate::vstate::vcpu::VcpuError;
 use crate::{DirtyBitmap, Vcpu, mem_size_mib};
@@ -466,7 +466,7 @@ impl Vm {
                     .iter()
                     .any(|r| r.inner().guest_memfd != 0);
                 self.guest_memory()
-                    .dump(&mut Bounce(&file, secret_hidden))
+                    .dump(&mut MaybeBounce(&file, secret_hidden))
                     .and_then(|_| self.swiotlb_regions().dump(&mut file))?;
                 self.reset_dirty_bitmap();
                 self.guest_memory().reset_dirty();