vmm: fix worker thread panic

If the worker thread panics when trying to convert memory to or from
private, it leaves the VMM process waiting indefinitely for the sender
to send some sort of message over the channel. Rather than panicking, we
should print an error and send a message back over the channel to stop
the VM.

Signed-off-by: Jake Correnti <[email protected]>

Author: jakecorrenti

src/vmm/src/worker.rs

@@ -15,7 +15,9 @@ use libc::{fallocate, madvise, FALLOC_FL_KEEP_SIZE, FALLOC_FL_PUNCH_HOLE, MADV_D
 #[cfg(feature = "tee")]
 use std::ffi::c_void;
 #[cfg(feature = "tee")]
-use vm_memory::{guest_memory::GuestMemory, GuestAddress, GuestMemoryRegion, MemoryRegionAddress};
+use vm_memory::{
+    guest_memory::GuestMemory, Address, GuestAddress, GuestMemoryRegion, MemoryRegionAddress,
+};
 
 pub fn start_worker_thread(
     vmm: Arc<Mutex<super::Vmm>>,
@@ -67,15 +69,15 @@ impl super::Vmm {
 
     #[cfg(feature = "tee")]
     fn convert_memory(&self, sender: Sender<bool>, properties: MemoryProperties) {
-        let (guest_memfd, region_start) = self
-            .kvm_vm()
-            .guest_memfd_get(properties.gpa)
-            .unwrap_or_else(|| {
-                panic!(
-                    "unable to find KVM guest_memfd for memory region corresponding to GPA 0x{:x}",
-                    properties.gpa
-                )
-            });
+        let Some((guest_memfd, region_start)) = self.kvm_vm().guest_memfd_get(properties.gpa)
+        else {
+            error!(
+                "unable to find KVM guest_memfd for memory region corresponding to GPA 0x{:x}",
+                properties.gpa
+            );
+            sender.send(false).unwrap();
+            return;
+        };
 
         let attributes: u64 = if properties.private {
             KVM_MEMORY_ATTRIBUTE_PRIVATE as u64
@@ -90,10 +92,11 @@ impl super::Vmm {
             flags: 0,
         };
 
-        self.kvm_vm()
-            .fd()
-            .set_memory_attributes(attr)
-            .unwrap_or_else(|_| panic!("unable to set memory attributes for memory region corresponding to guest address 0x{:x}", properties.gpa));
+        if self.kvm_vm().fd().set_memory_attributes(attr).is_err() {
+            error!("unable to set memory attributes for memory region corresponding to guest address 0x{:x}", properties.gpa);
+            sender.send(false).unwrap();
+            return;
+        }
 
         let region = self
             .guest_memory()
@@ -112,10 +115,14 @@ impl super::Vmm {
         if properties.private {
             let region_addr = MemoryRegionAddress(offset);
 
-            let host_startaddr = region
-                .unwrap()
-                .get_host_address(region_addr)
-                .expect("host address corresponding to memory region address 0x{:x} not found");
+            let Ok(host_startaddr) = region.unwrap().get_host_address(region_addr) else {
+                error!(
+                    "host address corresponding to memory region address 0x{:x} not found",
+                    region_addr.raw_value()
+                );
+                sender.send(false).unwrap();
+                return;
+            };
 
             let ret = unsafe {
                 madvise(