implement CpuId as a FamStructWrapper over kvm_cpuid2

Since kvm_cpuid2 contains a flexible array member, we can implement
CpuId as a FamStructWrapper<kvm_cpuid2>. This allows users of
kvm-ioctls to work with safe code even when dealing with kvm_cpuid2.

Signed-off-by: Adrian Catangiu <[email protected]>

Author: acatangiu

Cargo.toml

@@ -13,3 +13,4 @@ kvm-v4_14_0 = []
 kvm-v4_20_0 = []
 
 [dependencies]
+vmm-sys-util = ">=0.2.0"

src/lib.rs

@@ -5,6 +5,10 @@
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
 
+#[macro_use]
+#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+extern crate vmm_sys_util;
+
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 mod x86;
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]

src/x86/fam_wrappers.rs

@@ -0,0 +1,37 @@
+// Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+use vmm_sys_util::fam::{FamStruct, FamStructWrapper};
+
+#[cfg(feature = "kvm-v4_14_0")]
+use super::bindings_v4_14_0::*;
+
+#[cfg(feature = "kvm-v4_20_0")]
+use super::bindings_v4_20_0::*;
+
+#[cfg(all(not(feature = "kvm-v4_14_0"), not(feature = "kvm-v4_20_0")))]
+use super::bindings_v4_20_0::*;
+
+/// Maximum number of CPUID entries that can be returned by a call to KVM ioctls.
+///
+/// See arch/x86/include/asm/kvm_host.h
+pub const KVM_MAX_CPUID_ENTRIES: usize = 80;
+
+// Implement the FamStruct trait for kvm_cpuid2.
+generate_fam_struct_impl!(
+    kvm_cpuid2,
+    kvm_cpuid_entry2,
+    entries,
+    u32,
+    nent,
+    KVM_MAX_CPUID_ENTRIES
+);
+
+/// Wrapper over the `kvm_cpuid2` structure.
+///
+/// The `kvm_cpuid2` structure contains a flexible array member. For details check the
+/// [KVM API](https://www.kernel.org/doc/Documentation/virtual/kvm/api.txt)
+/// documentation on `kvm_cpuid2`. To provide safe access to
+/// the array elements, this type is implemented using
+/// [FamStructWrapper](../vmm_sys_util/fam/struct.FamStructWrapper.html).
+pub type CpuId = FamStructWrapper<kvm_cpuid2>;

src/x86/mod.rs

@@ -1,6 +1,8 @@
 // Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+mod fam_wrappers;
+
 #[cfg(feature = "kvm-v4_14_0")]
 mod bindings_v4_14_0;
 #[cfg(feature = "kvm-v4_20_0")]
@@ -21,4 +23,6 @@ pub mod bindings {
 
     #[cfg(all(not(feature = "kvm-v4_14_0"), not(feature = "kvm-v4_20_0")))]
     pub use super::bindings_v4_20_0::*;
+
+    pub use super::fam_wrappers::*;
 }