msi: fix size of interrupts HashMap

We are using a HashMap to track the interrupt routes we use in the
system. The index to the HashMap is the GSI of the interrupt route.
We know the maximum number of GSIs we have available so pre-allocate the
space for the HashMap to avoid reallocations at runtime.

Signed-off-by: Babis Chalios <[email protected]>

Author: bchalios

src/vmm/src/vstate/vm.rs

@@ -28,8 +28,8 @@ use vm_device::interrupt::{
 use vmm_sys_util::errno;
 use vmm_sys_util::eventfd::EventFd;
 
-use crate::arch::host_page_size;
 pub use crate::arch::{ArchVm as Vm, ArchVmError, VmState};
+use crate::arch::{GSI_MSI_END, host_page_size};
 use crate::logger::info;
 use crate::persist::CreateSnapshotError;
 use crate::snapshot::Persist;
@@ -322,7 +322,7 @@ impl Vm {
             fd,
             max_memslots: kvm.max_nr_memslots(),
             guest_memory: GuestMemoryMmap::default(),
-            interrupts: Mutex::new(HashMap::new()),
+            interrupts: Mutex::new(HashMap::with_capacity(GSI_MSI_END as usize + 1)),
             resource_allocator: Mutex::new(ResourceAllocator::new()),
             mmio_bus: Arc::new(vm_device::Bus::new()),
         })