fix(mmio): handle unaligned and partial read/write

Signed-off-by: Changyuan Lyu <[email protected]>
google · Nov 18, 2024 · 8df69f1 · 8df69f1
1 parent b32061f
commit 8df69f1
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Showing 6 changed files with 421 additions and 16 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -21,6 +21,7 @@ assert_matches = "1"
 proc-macro2 = "1"
 syn = { version = "2", features = ["full"] }
 quote = { version = "1" }
+rstest = "0.23"
 
 [profile.release]
 lto = true

diff --git a/alioth/Cargo.toml b/alioth/Cargo.toml
@@ -28,3 +28,4 @@ io-uring = "0.7"
 
 [dev-dependencies]
 assert_matches.workspace = true
+rstest.workspace = true
diff --git a/alioth/src/hv/kvm/vmexit.rs b/alioth/src/hv/kvm/vmexit.rs
@@ -23,11 +23,10 @@ impl KvmVcpu {
     #[cfg(target_endian = "little")]
     pub(super) fn handle_mmio(&mut self) -> Result<VmExit, Error> {
         let kvm_mmio = unsafe { &self.kvm_run.exit.mmio };
-        let data = u64::from_ne_bytes(kvm_mmio.data) & u64::MAX >> (64 - (kvm_mmio.len << 3));
         let exit = VmExit::Mmio {
             addr: kvm_mmio.phys_addr,
             write: if kvm_mmio.is_write > 0 {
-                Some(data)
+                Some(u64::from_ne_bytes(kvm_mmio.data))
             } else {
                 None
             },
Original file line number	Diff line number	Diff line change
Expand Up		@@ -28,3 +28,4 @@ io-uring = "0.7"

		[dev-dependencies]
		assert_matches.workspace = true
		rstest.workspace = true