plugin_proto: add helpers to convert CPUID data between KVM and protobuf

We need to convert between protobuf and KVM format of cpuid data in
several places, so let's add helpers to plugin_proto crate.

TEST=cargo test --features plugin; cargo test -p kvm
BUG=chromium:800626

Change-Id: Ida7b59825d2146b0d02711e441f477d90dd4263a
Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/939660
Reviewed-by: Zach Reizner <zachr@chromium.org>

4 files changed, 36 insertions, 11 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 523e4e3..fa6f505 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -176,6 +176,7 @@ name = "plugin_proto"
 version = "0.10.0"
 dependencies = [
  "gcc 0.3.54 (registry+https://github.com/rust-lang/crates.io-index)",
+ "kvm_sys 0.1.0",
  "protobuf 1.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "protoc-rust 1.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
diff --git a/crosvm_plugin/src/lib.rs b/crosvm_plugin/src/lib.rs
index 6f56341..250692a 100644
--- a/crosvm_plugin/src/lib.rs
+++ b/crosvm_plugin/src/lib.rs
@@ -43,8 +43,7 @@ use sys_util::Scm;
 
 use kvm::dirty_log_bitmap_size;
 
-use kvm_sys::{kvm_regs, kvm_sregs, kvm_fpu, kvm_debugregs, kvm_msr_entry, kvm_cpuid_entry2,
-              KVM_CPUID_FLAG_SIGNIFCANT_INDEX};
+use kvm_sys::{kvm_regs, kvm_sregs, kvm_fpu, kvm_debugregs, kvm_msr_entry, kvm_cpuid_entry2};
 
 use plugin_proto::*;
 
@@ -753,15 +752,7 @@ impl crosvm_vcpu {
         {
             let set_cpuid_entries: &mut RepeatedField<CpuidEntry> = r.mut_set_cpuid().mut_entries();
             for cpuid_entry in cpuid_entries.iter() {
-                let mut entry = CpuidEntry::new();
-                entry.function = cpuid_entry.function;
-                entry.has_index = cpuid_entry.flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX != 0;
-                entry.index = cpuid_entry.index;
-                entry.eax = cpuid_entry.eax;
-                entry.ebx = cpuid_entry.ebx;
-                entry.ecx = cpuid_entry.ecx;
-                entry.edx = cpuid_entry.edx;
-                set_cpuid_entries.push(entry);
+                set_cpuid_entries.push(cpuid_kvm_to_proto(cpuid_entry));
             }
         }
         self.vcpu_transaction(&r)?;
diff --git a/plugin_proto/Cargo.toml b/plugin_proto/Cargo.toml
index cb6c7fd..bb43452 100644
--- a/plugin_proto/Cargo.toml
+++ b/plugin_proto/Cargo.toml
@@ -6,6 +6,7 @@ build = "build.rs"
 
 [dependencies]
 protobuf = "*"
+kvm_sys = { path = "../kvm_sys" }
 
 [build-dependencies]
 gcc = "=0.3.54"
diff --git a/plugin_proto/src/lib.rs b/plugin_proto/src/lib.rs
index 7f0d66c..c28635a 100644
--- a/plugin_proto/src/lib.rs
+++ b/plugin_proto/src/lib.rs
@@ -1,2 +1,34 @@
 extern crate protobuf;
+extern crate kvm_sys;
 include!(concat!(env!("OUT_DIR"), "/proto_include.rs"));
+
+/// Converts protobuf representation of CpuId data into KVM format.
+pub fn cpuid_proto_to_kvm(entry: &CpuidEntry) -> kvm_sys::kvm_cpuid_entry2 {
+    // Safe: C structures are expected to be zero-initialized.
+    let mut e: kvm_sys::kvm_cpuid_entry2 = unsafe { std::mem::zeroed() };
+    e.function = entry.function;
+    if entry.has_index {
+        e.flags = kvm_sys::KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
+    }
+    e.index = entry.index;
+    e.eax = entry.eax;
+    e.ebx = entry.ebx;
+    e.ecx = entry.ecx;
+    e.edx = entry.edx;
+
+    e
+}
+
+/// Converts KVM representation of CpuId data into protobuf format.
+pub fn cpuid_kvm_to_proto(entry: &kvm_sys::kvm_cpuid_entry2) -> CpuidEntry {
+    let mut e = CpuidEntry::new();
+    e.function = entry.function;
+    e.has_index = entry.flags & kvm_sys::KVM_CPUID_FLAG_SIGNIFCANT_INDEX != 0;
+    e.index = entry.index;
+    e.eax = entry.eax;
+    e.ebx = entry.ebx;
+    e.ecx = entry.ecx;
+    e.edx = entry.edx;
+
+    e
+}