Pin static references to VCpu and VirtualMachine

Author: ALSchwalm

mythril/src/lib.rs

@@ -5,6 +5,7 @@
 #![feature(get_mut_unchecked)]
 #![feature(fixed_size_array)]
 #![feature(panic_info_message)]
+#![feature(pin_static_ref)]
 #![feature(array_value_iter)]
 #![feature(alloc_error_handler)]
 #![feature(lang_items)]

mythril/src/vcpu.rs

@@ -51,7 +51,7 @@ pub fn mp_entry_point() -> ! {
         vm
     };
 
-    let vcpu = VCpu::new(vm).expect("Failed to create vcpu");
+    let mut vcpu = VCpu::new(vm).expect("Failed to create vcpu");
 
     let vm_id = vm.id;
     let is_vm_bsp = vm.bsp_id() == core_id;
@@ -99,7 +99,7 @@ pub enum InjectedInterruptType {
 /// ultimate handling will occur within an emulated device in the `VirtualMachine`'s
 /// `DeviceMap`)
 pub struct VCpu {
-    pub vm: &'static VirtualMachine,
+    pub vm: Pin<&'static VirtualMachine>,
     pub vmcs: vmcs::ActiveVmcs,
     pub local_apic: virtdev::lapic::LocalApic,
     pending_interrupts: BTreeMap<u8, InjectedInterruptType>,
@@ -112,7 +112,9 @@ impl VCpu {
     /// Note that the result must be `Pin`, as the `VCpu` pushes its own
     /// address on to the per-core host stack so it can be retrieved on
     /// VMEXIT.
-    pub fn new(vm: &'static VirtualMachine) -> Result<&'static mut Self> {
+    pub fn new(
+        vm: Pin<&'static VirtualMachine>,
+    ) -> Result<Pin<&'static mut Self>> {
         let vmx = vmx::Vmx::enable()?;
         let vmcs = vmcs::Vmcs::new()?.activate(vmx)?;
 
@@ -155,7 +157,7 @@ impl VCpu {
         Self::initialize_guest_vmcs(vcpu)?;
         Self::initialize_ctrl_vmcs(&mut vcpu.vmcs)?;
 
-        Ok(vcpu)
+        Ok(Pin::new(vcpu))
     }
 
     pub fn inject_interrupt(

mythril/src/virtdev/lapic.rs

@@ -4,6 +4,7 @@ use crate::memory;
 use crate::percore;
 use crate::vm;
 use core::convert::TryFrom;
+use core::pin::Pin;
 use core::sync::atomic::AtomicU32;
 use num_enum::TryFromPrimitive;
 
@@ -141,7 +142,7 @@ impl LocalApic {
 
     fn process_interrupt_command(
         &mut self,
-        vm: &vm::VirtualMachine,
+        vm: Pin<&vm::VirtualMachine>,
         value: u32,
     ) -> Result<()> {
         let mode = DeliveryMode::try_from((value >> 8) as u8 & 0b111)?;
@@ -221,7 +222,7 @@ impl LocalApic {
 
     pub fn register_write(
         &mut self,
-        vm: &vm::VirtualMachine,
+        vm: Pin<&vm::VirtualMachine>,
         offset: u16,
         value: u32,
     ) -> Result<()> {

mythril/src/vm.rs

@@ -23,6 +23,7 @@ use arraydeque::ArrayDeque;
 use arrayvec::ArrayVec;
 use core::default::Default;
 use core::mem;
+use core::pin::Pin;
 use core::sync::atomic::AtomicU32;
 use spin::RwLock;
 
@@ -92,7 +93,7 @@ pub enum VirtualMachineMsg {
 struct VirtualMachineContext {
     core_id: percore::CoreId,
 
-    vm: &'static VirtualMachine,
+    vm: Pin<&'static VirtualMachine>,
 
     /// The per-core RX message queue
     msgqueue: RwLock<ArrayDeque<[VirtualMachineMsg; MAX_PENDING_MSG]>>,
@@ -138,13 +139,13 @@ impl VirtualMachineSet {
         }
 
         // Initialize the per-VM local apic access page
-        vm.setup_guest_local_apic_page()?;
+        Pin::static_ref(vm).setup_guest_local_apic_page()?;
 
         // Create the communication queues
         for cpu in vm.cpus.iter() {
             self.contexts.push(VirtualMachineContext {
                 core_id: *cpu,
-                vm: vm,
+                vm: Pin::static_ref(vm),
                 msgqueue: RwLock::new(ArrayDeque::new()),
             })
         }
@@ -194,12 +195,15 @@ impl VirtualMachineSet {
     pub unsafe fn get_by_core_id(
         &self,
         core_id: percore::CoreId,
-    ) -> Option<&'static VirtualMachine> {
+    ) -> Option<Pin<&'static VirtualMachine>> {
         self.context_by_core_id(core_id).map(|context| context.vm)
     }
 
     /// Get a VirtualMachine by its vmid
-    pub fn get_by_vm_id(&self, vmid: u32) -> Option<&'static VirtualMachine> {
+    pub fn get_by_vm_id(
+        &self,
+        vmid: u32,
+    ) -> Option<Pin<&'static VirtualMachine>> {
         self.context_by_vm_id(vmid).map(|context| context.vm)
     }
 
@@ -479,7 +483,7 @@ impl VirtualMachine {
 
     /// Setup the local APIC access page for the guest. This _must_ be called
     /// only once the VirtualMachine is in a final location.
-    pub fn setup_guest_local_apic_page(&'static self) -> Result<()> {
+    pub fn setup_guest_local_apic_page(self: Pin<&'static Self>) -> Result<()> {
         // Map the guest local apic addr to the access page. This will be set in each
         // core's vmcs
         let apic_frame = memory::HostPhysFrame::from_start_address(