Draft: Add virtio balloon

.gitignore

@@ -1 +1,4 @@
 /target
+
+# Our CI script wants this in our project directory, but this is a compiled binary file
+hermit-loader*

Cargo.toml

@@ -69,6 +69,8 @@ trace = []
 udp = ["smoltcp", "smoltcp/socket-udp"]
 vga = []
 vsock = ["pci"]
+balloon = ["pci"]
+allocation-stats = ["talc/counters"]
 
 [lints.rust]
 rust_2018_idioms = "warn"
@@ -99,7 +101,7 @@ unreadable_literal = "warn"
 
 [dependencies]
 hermit-macro = { version = "=0.1.0", path = "hermit-macro" }
-virtio = { package = "virtio-spec", version = "0.2", features = ["alloc", "mmio", "nightly", "zerocopy"] }
+virtio = { package = "virtio-spec", version = "0.3.2", features = ["alloc", "mmio", "nightly", "zerocopy"] }
 ahash = { version = "0.8", default-features = false }
 align-address = "0.3"
 anstyle = { version = "1", default-features = false }
@@ -130,7 +132,7 @@ shell-words = { version = "1.1", default-features = false }
 simple-shell = { version = "0.0.1", optional = true }
 smallvec = { version = "1", features = ["const_new"] }
 take-static = "0.1"
-talc = { version = "4" }
+talc = { git = "https://github.com/hcsch/talc.git", version = "4.4.3", branch = "try-without-oom-handler" }
 time = { version = "0.3", default-features = false }
 volatile = "0.6"
 zerocopy = { version = "0.8", default-features = false }
@@ -204,3 +206,6 @@ members = [
 exclude = [
 	"hermit-builtins",
 ]
+
+[profile.release]
+debug = true

hermit-builtins/Cargo.toml

@@ -10,3 +10,6 @@ libm = "0.2"
 crate-type = ["staticlib"]
 
 [workspace]
+
+[profile.release]
+debug = true

src/arch/x86_64/kernel/processor.rs

@@ -1089,6 +1089,8 @@ fn triple_fault() -> ! {
 }
 
 fn qemu_exit(success: bool) {
+	// Write exit code into isa-debug-exit port.
+	// For a value `e` written into the port, QEMU will exit with `(e << 1) | 1`.
 	let code = if success { 3 >> 1 } else { 0 };
 	unsafe {
 		Port::<u32>::new(0xf4).write(code);

src/config.rs

@@ -7,7 +7,8 @@ pub(crate) const USER_STACK_SIZE: usize = 0x0010_0000;
 #[cfg(any(
 	all(any(feature = "tcp", feature = "udp"), not(feature = "rtl8139")),
 	feature = "fuse",
-	feature = "vsock"
+	feature = "vsock",
+	feature = "balloon"
 ))]
 pub(crate) const VIRTIO_MAX_QUEUE_SIZE: u16 = if cfg!(feature = "pci") { 2048 } else { 1024 };