dragonball: Fix unnecessary_cast warnings

As we bumped the rust toolchain to 1.66.0, some new warnings have been
raised due to unnecessary_cast.

Let's fix them all here.

For more info about the warnings, please, take a look at:
https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

src/dragonball/src/address_space_manager.rs

@@ -401,9 +401,9 @@ impl AddressSpaceMgr {
             let flags = 0u32;
 
             let mem_region = kvm_userspace_memory_region {
-                slot: slot as u32,
+                slot,
                 guest_phys_addr: reg.start_addr().raw_value(),
-                memory_size: reg.len() as u64,
+                memory_size: reg.len(),
                 userspace_addr: host_addr as u64,
                 flags,
             };
@@ -421,7 +421,7 @@ impl AddressSpaceMgr {
         self.base_to_slot
             .lock()
             .unwrap()
-            .insert(reg.start_addr().raw_value(), slot as u32);
+            .insert(reg.start_addr().raw_value(), slot);
 
         Ok(())
     }

src/dragonball/src/resource_manager.rs

@@ -435,10 +435,7 @@ impl ResourceManager {
                         constraint.max = r.1 as u64;
                     }
                     match self.allocate_pio_address(&constraint) {
-                        Some(base) => Resource::PioAddressRange {
+                        Some(base) => Resource::PioAddressRange { base, size: *size },
-                            base: base as u16,
-                            size: *size,
-                        },
                         None => {
                             if let Err(e) = self.free_device_resources(&resources) {
                                 return Err(e);

src/dragonball/src/signal_handler.rs

@@ -41,7 +41,7 @@ extern "C" fn sigsys_handler(num: c_int, info: *mut siginfo_t, _unused: *mut c_v
     let si_code = unsafe { (*info).si_code };
 
     // Sanity check. The condition should never be true.
-    if num != si_signo || num != SIGSYS || si_code != SYS_SECCOMP_CODE as i32 {
+    if num != si_signo || num != SIGSYS || si_code != SYS_SECCOMP_CODE {
         // Safe because we're terminating the process anyway.
         unsafe { _exit(i32::from(super::EXIT_CODE_UNEXPECTED_ERROR)) };
     }

src/dragonball/src/vcpu/x86_64.rs

@@ -96,14 +96,14 @@ impl Vcpu {
         if let Some(start_addr) = kernel_start_addr {
             dbs_arch::regs::setup_regs(
                 &self.fd,
-                start_addr.raw_value() as u64,
+                start_addr.raw_value(),
                 dbs_boot::layout::BOOT_STACK_POINTER,
                 dbs_boot::layout::BOOT_STACK_POINTER,
                 dbs_boot::layout::ZERO_PAGE_START,
             )
             .map_err(VcpuError::REGSConfiguration)?;
             dbs_arch::regs::setup_fpu(&self.fd).map_err(VcpuError::FPUConfiguration)?;
-            let gdt_table: [u64; dbs_boot::layout::BOOT_GDT_MAX as usize] = [
+            let gdt_table: [u64; dbs_boot::layout::BOOT_GDT_MAX] = [
                 gdt_entry(0, 0, 0),            // NULL
                 gdt_entry(0xa09b, 0, 0xfffff), // CODE
                 gdt_entry(0xc093, 0, 0xfffff), // DATA
@@ -129,7 +129,7 @@ impl Vcpu {
     fn set_cpuid(&mut self, vcpu_config: &VcpuConfig) -> Result<()> {
         let cpuid_vm_spec = VmSpec::new(
             self.id,
-            vcpu_config.max_vcpu_count as u8,
+            vcpu_config.max_vcpu_count,
             vcpu_config.threads_per_core,
             vcpu_config.cores_per_die,
             vcpu_config.dies_per_socket,

src/dragonball/src/vm/x86_64.rs

@@ -81,10 +81,10 @@ fn configure_system<M: GuestMemory>(
     if mem_end < mmio_start {
         add_e820_entry(
             &mut params.0,
-            himem_start.raw_value() as u64,
+            himem_start.raw_value(),
             // it's safe to use unchecked_offset_from because
             // mem_end > himem_start
-            mem_end.unchecked_offset_from(himem_start) as u64 + 1,
+            mem_end.unchecked_offset_from(himem_start) + 1,
             bootparam::E820_RAM,
         )
         .map_err(Error::BootSystem)?;
@@ -103,7 +103,7 @@ fn configure_system<M: GuestMemory>(
                 &mut params.0,
                 mmio_end.raw_value() + 1,
                 // it's safe to use unchecked_offset_from because mem_end > mmio_end
-                mem_end.unchecked_offset_from(mmio_end) as u64,
+                mem_end.unchecked_offset_from(mmio_end),
                 bootparam::E820_RAM,
             )
             .map_err(Error::BootSystem)?;