refactor: Remove GuestMemoryExtension::with_size

It was only used in test code, but test code has its own utilities for
creating guest memory, so just use those, and remove the production fn.

Also remove documentation references to guard pages because they are a
thing of the past.

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

Author: roypat

src/vmm/src/builder.rs

@@ -969,6 +969,7 @@ pub mod tests {
     use crate::devices::virtio::{TYPE_BALLOON, TYPE_BLOCK, TYPE_RNG};
     use crate::mmds::data_store::{Mmds, MmdsVersion};
     use crate::mmds::ns::MmdsNetworkStack;
+    use crate::utilities::test_utils::{arch_mem, single_region_mem, single_region_mem_at};
     use crate::vmm_config::balloon::{BalloonBuilder, BalloonDeviceConfig, BALLOON_DEV_ID};
     use crate::vmm_config::boot_source::DEFAULT_KERNEL_CMDLINE;
     use crate::vmm_config::drive::{BlockBuilder, BlockDeviceConfig};
@@ -1040,7 +1041,7 @@ pub mod tests {
     }
 
     pub(crate) fn default_vmm() -> Vmm {
-        let guest_memory = GuestMemoryMmap::with_size(128, false).unwrap();
+        let guest_memory = arch_mem(128 << 20);
 
         let vcpus_exit_evt = EventFd::new(libc::EFD_NONBLOCK)
             .map_err(VmmError::EventFd)
@@ -1268,8 +1269,6 @@ pub mod tests {
         );
     }
 
-    use crate::utilities::test_utils::{single_region_mem, single_region_mem_at};
-
     #[test]
     fn test_load_initrd_unaligned() {
         let image = vec![1, 2, 3, 4];
@@ -1289,7 +1288,7 @@ pub mod tests {
     #[test]
     fn test_create_vcpus() {
         let vcpu_count = 2;
-        let guest_memory = GuestMemoryMmap::with_size(128, false).unwrap();
+        let guest_memory = arch_mem(128 << 20);
 
         #[allow(unused_mut)]
         let mut vm = Vm::new(vec![]).unwrap();

src/vmm/src/vstate/memory.rs

@@ -59,16 +59,13 @@ where
     /// Creates a GuestMemoryMmap with `size` in MiB backed by a memfd.
     fn memfd_backed(mem_size_mib: usize, track_dirty_pages: bool) -> Result<Self, MemoryError>;
 
-    /// Creates a GuestMemoryMmap with `size` in MiB and guard pages.
-    fn with_size(size: usize, track_dirty_pages: bool) -> Result<Self, MemoryError>;
-
-    /// Creates a GuestMemoryMmap from raw regions with guard pages.
+    /// Creates a GuestMemoryMmap from raw regions.
     fn from_raw_regions(
         regions: &[(GuestAddress, usize)],
         track_dirty_pages: bool,
     ) -> Result<Self, MemoryError>;
 
-    /// Creates a GuestMemoryMmap from raw regions with guard pages.
+    /// Creates a GuestMemoryMmap from raw regions.
     fn from_raw_regions_file(
         regions: Vec<(FileOffset, GuestAddress, usize)>,
         track_dirty_pages: bool,
@@ -139,14 +136,6 @@ impl GuestMemoryExtension for GuestMemoryMmap {
         Self::from_raw_regions_file(regions, track_dirty_pages, true)
     }
 
-    /// Creates a GuestMemoryMmap with `size` in MiB and guard pages backed by anonymous memory.
-    fn with_size(size: usize, track_dirty_pages: bool) -> Result<Self, MemoryError> {
-        let mem_size = size << 20;
-        let regions = crate::arch::arch_memory_regions(mem_size);
-
-        Self::from_raw_regions(&regions, track_dirty_pages)
-    }
-
     /// Creates a GuestMemoryMmap from raw regions backed by anonymous memory.
     fn from_raw_regions(
         regions: &[(GuestAddress, usize)],
@@ -174,7 +163,7 @@ impl GuestMemoryExtension for GuestMemoryMmap {
         GuestMemoryMmap::from_regions(regions).map_err(MemoryError::VmMemoryError)
     }
 
-    /// Creates a GuestMemoryMmap from raw regions with guard pages backed by file.
+    /// Creates a GuestMemoryMmap from raw regions backed by file.
     fn from_raw_regions_file(
         regions: Vec<(FileOffset, GuestAddress, usize)>,
         track_dirty_pages: bool,