Make mmap_unix.rs and mmap_xen.rs not mutually exclusive

Now that all tension between these two modules is resolves (e.g. no more
code depends on exactly one of these being defined, and tests can
support iterating over multiple supported backends), drop all the
`cfg(not(feature = "xen"))` from across the code base.

Signed-off-by: Patrick Roy <roypat@amazon.co.uk>

Author: roypat

CHANGELOG.md

@@ -24,6 +24,9 @@
   Change return type of `GuestRegionMmap::new` from `Result` to `Option`.
 - \[#324](https:////github.com/rust-vmm/vm-memory/pull/324)\] `GuestMemoryRegion::bitmap()` now returns a `BitmapSlice`. Accessing the full bitmap is now possible only if the type of the memory region is know, for example with `MmapRegion::bitmap()`.
 - \[[#339](https://github.com/rust-vmm/vm-memory/pull/339)\] Implement `Bytes::load()` and `Bytes::store()` with `get_slices()` instead of `to_region_addr()`
+- \[[#317](https://github.com/rust-vmm/vm-memory/pull/317)\]: Make `xen` feature additive, meaning enabling it
+  no longer disables the `mmap_unix` module at compile time. For this, various Xen-related structs had to be
+  renamed due to naming conflicts.
 
 ### Removed
 

src/bytes.rs

@@ -331,7 +331,7 @@ pub trait Bytes<A> {
     /// * Read bytes from /dev/urandom (uses the `backend-mmap` feature)
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", feature = "rawfd", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", feature = "rawfd", target_family = "unix"))]
     /// # {
     /// # use vm_memory::{Address, GuestMemory, Bytes, GuestAddress, GuestMemoryMmap};
     /// # use std::fs::File;

src/guest_memory.rs

@@ -176,7 +176,7 @@ impl FileOffset {
 /// # Examples (uses the `backend-mmap` and `backend-atomic` features)
 ///
 /// ```
-/// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+/// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
 /// # {
 /// # use std::sync::Arc;
 /// # use vm_memory::{GuestAddress, GuestAddressSpace, GuestMemory, GuestMemoryMmap};
@@ -294,7 +294,7 @@ pub trait GuestMemory {
     ///   `backend-mmap` feature)
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # {
     /// # use vm_memory::{GuestAddress, GuestMemory, GuestMemoryRegion, GuestMemoryMmap};
     /// #
@@ -318,7 +318,7 @@ pub trait GuestMemory {
     /// # Examples (uses the `backend-mmap` feature)
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # {
     /// # use vm_memory::{Address, GuestAddress, GuestMemory, GuestMemoryMmap};
     /// #
@@ -433,7 +433,7 @@ pub trait GuestMemory {
     /// # Examples (uses the `backend-mmap` feature)
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # {
     /// # use vm_memory::{GuestAddress, GuestMemory, GuestMemoryMmap};
     /// #
@@ -592,9 +592,9 @@ impl<T: GuestMemory + ?Sized> Bytes<GuestAddress> for T {
     /// * Write a slice at guestaddress 0x1000. (uses the `backend-mmap` feature)
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # {
-    /// # use vm_memory::{Bytes, GuestAddress, mmap::GuestMemoryMmap};
+    /// # use vm_memory::{Bytes, GuestAddress, GuestMemoryMmap};
     /// #
     /// # let start_addr = GuestAddress(0x1000);
     /// # let mut gm = GuestMemoryMmap::<()>::from_ranges(&vec![(start_addr, 0x400)])
@@ -620,9 +620,9 @@ impl<T: GuestMemory + ?Sized> Bytes<GuestAddress> for T {
     /// * Read a slice of length 16 at guestaddress 0x1000. (uses the `backend-mmap` feature)
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # {
-    /// # use vm_memory::{Bytes, GuestAddress, mmap::GuestMemoryMmap};
+    /// # use vm_memory::{Bytes, GuestAddress, GuestMemoryMmap};
     /// #
     /// let start_addr = GuestAddress(0x1000);
     /// let mut gm = GuestMemoryMmap::<()>::from_ranges(&vec![(start_addr, 0x400)])

src/lib.rs

@@ -67,14 +67,13 @@ pub use io::{ReadVolatile, WriteVolatile};
 #[cfg(feature = "backend-mmap")]
 pub mod mmap;
 
-#[cfg(all(feature = "backend-mmap", feature = "xen", target_family = "unix"))]
-pub use mmap::{MmapRange, MmapXenFlags};
-
 #[cfg(all(feature = "xen", target_family = "unix"))]
-pub use mmap::xen::{GuestMemoryXen, MmapRegion as MmapRegionXen};
+pub use mmap::xen::{GuestMemoryXen, MmapRange, MmapRegion as MmapRegionXen, MmapXenFlags};
 
-#[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
-pub use mmap::unix::{Error as MmapRegionError, GuestMemoryMmap, GuestRegionMmap, MmapRegion};
+#[cfg(all(feature = "backend-mmap", target_family = "unix"))]
+pub use mmap::unix::{
+    Error as MmapRegionError, GuestMemoryMmap, GuestRegionMmap, MmapRegion, MmapRegionBuilder,
+};
 
 #[cfg(windows)]
 pub use crate::mmap::windows::{

src/mmap/mod.rs

@@ -15,7 +15,7 @@
 // re-export for backward compat, as the trait used to be defined in mmap.rs
 pub use crate::bitmap::NewBitmap;
 
-#[cfg(all(not(feature = "xen"), target_family = "unix"))]
+#[cfg(target_family = "unix")]
 pub(super) mod unix;
 
 #[cfg(all(feature = "xen", target_family = "unix"))]
@@ -40,13 +40,11 @@ pub(crate) mod tests {
     #![allow(clippy::undocumented_unsafe_blocks)]
     extern crate vmm_sys_util;
 
-    use super::*;
-
     use crate::bitmap::BS;
     use crate::{
         guest_memory, Address, Bytes, FileOffset, GuestAddress, GuestMemory, GuestMemoryError,
-        GuestMemoryRegion, GuestMemoryRegionBytes, GuestUsize, MemoryRegionAddress, VolatileMemory,
-        VolatileSlice,
+        GuestMemoryRegion, GuestMemoryRegionBytes, GuestUsize, MemoryRegionAddress, MmapRegion,
+        VolatileMemory, VolatileSlice,
     };
 
     use std::io::Write;
@@ -111,7 +109,7 @@ pub(crate) mod tests {
     any_backend! {
         #[cfg(all(windows, feature = "backend-mmap"))]
         Windows[crate::mmap::windows::GuestRegionWindows<()>],
-        #[cfg(all(unix, feature = "backend-mmap", not(feature = "xen")))]
+        #[cfg(all(unix, feature = "backend-mmap"))]
         Mmap[crate::mmap::unix::GuestRegionMmap<()>],
         #[cfg(all(unix, feature = "backend-mmap", feature = "xen"))]
         Xen[crate::mmap::xen::MmapRegion]
@@ -130,7 +128,7 @@ pub(crate) mod tests {
                 )
                 .unwrap(),
             ));
-            #[cfg(all(unix, feature = "backend-mmap", not(feature = "xen")))]
+            #[cfg(all(unix, feature = "backend-mmap"))]
             regions.push(AnyRegion::Mmap(
                 crate::mmap::unix::GuestRegionMmap::new(
                     MmapRegion::from_file(f_off.clone(), size).unwrap(),
@@ -140,8 +138,12 @@ pub(crate) mod tests {
             ));
             #[cfg(all(unix, feature = "backend-mmap", feature = "xen"))]
             regions.push(AnyRegion::Xen(
-                MmapRegion::from_range(MmapRange::new_unix(size, Some(f_off.clone()), addr))
-                    .unwrap(),
+                crate::MmapRegionXen::from_range(crate::MmapRange::new_unix(
+                    size,
+                    Some(f_off.clone()),
+                    addr,
+                ))
+                .unwrap(),
             ));
             regions
         }
@@ -160,14 +162,15 @@ pub(crate) mod tests {
                 )
                 .unwrap(),
             ));
-            #[cfg(all(unix, feature = "backend-mmap", not(feature = "xen")))]
+            #[cfg(all(unix, feature = "backend-mmap"))]
             regions.push(AnyRegion::Mmap(
                 crate::mmap::unix::GuestRegionMmap::new(MmapRegion::new(size).unwrap(), addr)
                     .unwrap(),
             ));
             #[cfg(all(unix, feature = "backend-mmap", feature = "xen"))]
             regions.push(AnyRegion::Xen(
-                MmapRegion::from_range(MmapRange::new_unix(size, None, addr)).unwrap(),
+                crate::MmapRegionXen::from_range(crate::MmapRange::new_unix(size, None, addr))
+                    .unwrap(),
             ));
             regions
         }

src/region.rs

@@ -124,7 +124,7 @@ pub trait GuestMemoryRegion: Bytes<MemoryRegionAddress, E = GuestMemoryError> {
     /// # Examples (uses the `backend-mmap` feature)
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # {
     /// # use vm_memory::{GuestAddress, MmapRegion, GuestRegionMmap, GuestMemoryRegion};
     /// # use vm_memory::volatile_memory::{VolatileMemory, VolatileSlice, VolatileRef};
@@ -154,7 +154,7 @@ pub trait GuestMemoryRegion: Bytes<MemoryRegionAddress, E = GuestMemoryError> {
     /// # Examples (uses the `backend-mmap` feature)
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # {
     /// #   use vm_memory::{GuestAddress, GuestMemory, GuestMemoryMmap, GuestRegionMmap};
     /// let addr = GuestAddress(0x1000);
@@ -335,10 +335,10 @@ impl<R: GuestMemoryRegionBytes> Bytes<MemoryRegionAddress> for R {
     /// * Write a slice at guest address 0x1200.
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # use vm_memory::{Bytes, GuestAddress, GuestMemoryMmap};
     /// #
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # {
     /// # let start_addr = GuestAddress(0x1000);
     /// # let mut gm = GuestMemoryMmap::<()>::from_ranges(&vec![(start_addr, 0x400)])
@@ -361,10 +361,10 @@ impl<R: GuestMemoryRegionBytes> Bytes<MemoryRegionAddress> for R {
     /// * Read a slice of length 16 at guestaddress 0x1200.
     ///
     /// ```
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # use vm_memory::{Bytes, GuestAddress, GuestMemoryMmap};
     /// #
-    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix", not(feature = "xen")))]
+    /// # #[cfg(all(feature = "backend-mmap", target_family = "unix"))]
     /// # {
     /// # let start_addr = GuestAddress(0x1000);
     /// # let mut gm = GuestMemoryMmap::<()>::from_ranges(&vec![(start_addr, 0x400)])