From 5ada3f59c8b7cafff923e7b3032bb6209a6473fc Mon Sep 17 00:00:00 2001
From: Samuel Ortiz <sameo@linux.intel.com>
Date: Wed, 3 Feb 2021 00:02:50 +0100
Subject: [PATCH] hypervisor: emulator: Emulate MOVZX

MOV R/RM is a special case of MOVZX, so we generalize the mov_r_rm macro
to make it support both instructions.

Fixes: #2227

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
---
 .../src/arch/x86/emulator/instructions/mov.rs | 49 +++++++++++++++++--
 hypervisor/src/arch/x86/emulator/mod.rs       |  8 ++-
 2 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/hypervisor/src/arch/x86/emulator/instructions/mov.rs b/hypervisor/src/arch/x86/emulator/instructions/mov.rs
index 2aebe6253..ee696c577 100644
--- a/hypervisor/src/arch/x86/emulator/instructions/mov.rs
+++ b/hypervisor/src/arch/x86/emulator/instructions/mov.rs
@@ -74,21 +74,27 @@ macro_rules! mov_rm_imm {
     };
 }
 
-macro_rules! mov_r_rm {
-    ($bound:ty) => {
+macro_rules! movzx {
+    ($src_op_size:ty, $dest_op_size:ty) => {
         fn emulate(
             &self,
             insn: &Instruction,
             state: &mut T,
             platform: &mut dyn PlatformEmulator<CpuState = T>,
         ) -> Result<(), EmulationError<Exception>> {
-            let src_value = get_op(&insn, 1, std::mem::size_of::<$bound>(), state, platform)
-                .map_err(EmulationError::PlatformEmulationError)?;
+            let src_value = get_op(
+                &insn,
+                1,
+                std::mem::size_of::<$src_op_size>(),
+                state,
+                platform,
+            )
+            .map_err(EmulationError::PlatformEmulationError)?;
 
             set_op(
                 &insn,
                 0,
-                std::mem::size_of::<$bound>(),
+                std::mem::size_of::<$dest_op_size>(),
                 state,
                 platform,
                 src_value,
@@ -102,6 +108,13 @@ macro_rules! mov_r_rm {
     };
 }
 
+// MOV r/rm is a special case of MOVZX, where both operands have the same size.
+macro_rules! mov_r_rm {
+    ($op_size:ty) => {
+        movzx!($op_size, $op_size);
+    };
+}
+
 macro_rules! mov_r_imm {
     ($bound:ty) => {
         fn emulate(
@@ -210,6 +223,32 @@ impl<T: CpuStateManager> InstructionHandler<T> for Mov_rm64_r64 {
     mov_rm_r!(u64);
 }
 
+// MOVZX
+pub struct Movzx_r16_rm8;
+impl<T: CpuStateManager> InstructionHandler<T> for Movzx_r16_rm8 {
+    movzx!(u16, u8);
+}
+
+pub struct Movzx_r32_rm8;
+impl<T: CpuStateManager> InstructionHandler<T> for Movzx_r32_rm8 {
+    movzx!(u32, u8);
+}
+
+pub struct Movzx_r64_rm8;
+impl<T: CpuStateManager> InstructionHandler<T> for Movzx_r64_rm8 {
+    movzx!(u64, u8);
+}
+
+pub struct Movzx_r32_rm16;
+impl<T: CpuStateManager> InstructionHandler<T> for Movzx_r32_rm16 {
+    movzx!(u32, u16);
+}
+
+pub struct Movzx_r64_rm16;
+impl<T: CpuStateManager> InstructionHandler<T> for Movzx_r64_rm16 {
+    movzx!(u64, u16);
+}
+
 #[cfg(test)]
 mod tests {
     #![allow(unused_mut)]
diff --git a/hypervisor/src/arch/x86/emulator/mod.rs b/hypervisor/src/arch/x86/emulator/mod.rs
index c26b5faa2..03e2d428a 100644
--- a/hypervisor/src/arch/x86/emulator/mod.rs
+++ b/hypervisor/src/arch/x86/emulator/mod.rs
@@ -518,7 +518,13 @@ impl<'a, T: CpuStateManager> Emulator<'a, T> {
             (mov, Mov_rm32_imm32),
             (mov, Mov_rm32_r32),
             (mov, Mov_rm64_imm32),
-            (mov, Mov_rm64_r64)
+            (mov, Mov_rm64_r64),
+            // MOVZX
+            (mov, Movzx_r16_rm8),
+            (mov, Movzx_r32_rm8),
+            (mov, Movzx_r64_rm8),
+            (mov, Movzx_r32_rm16),
+            (mov, Movzx_r64_rm16)
         );
 
         handler