alloc: Remove alloc_error_handler

The experimental alloc_error_handler feature was removed in Rust 1.71.0.
Starting from 1.71.0, Rust will panic when there's an allocation error
(OOM), which is the expected behaviour in SVSM (it will call the
SVSM-defined panic handler).

Remove alloc_error_handler mentions, and declare 1.71 as the minimal
Rust version for building linux-svsm.

Signed-off-by: Dov Murik <[email protected]>

Cargo.toml

@@ -10,6 +10,7 @@ name = "linux_svsm"
 authors = ["Tom Lendacky <[email protected]>", "Carlos Bilbao <[email protected]>"]
 version = "0.1.0"
 edition = "2021"
+rust-version = "1.71"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 

src/lib.rs

@@ -8,7 +8,6 @@
 
 #![feature(type_ascription)]
 #![feature(abi_x86_interrupt)]
-#![feature(alloc_error_handler)]
 // Disable the (implicitly-linked) standard library. #! defines behavior of the current module; as
 // we are in root, the entire crate is affected.
 #![no_std]

src/mem/alloc.rs

@@ -1141,12 +1141,6 @@ unsafe impl GlobalAlloc for SvsmAllocator {
 #[cfg_attr(not(test), global_allocator)]
 pub static mut ALLOCATOR: SvsmAllocator = SvsmAllocator::new();
 
-#[cfg(not(test))]
-#[alloc_error_handler]
-fn alloc_error_handler(layout: alloc::alloc::Layout) -> ! {
-    panic!("Allocation failed: {:?}\n", layout)
-}
-
 /// Create a stack of size stack_pages and add a guard page
 /// also make the stack user accessible if needed
 pub fn mem_create_stack(stack_pages: u64, user_space: bool) -> VirtAddr {