KVM: x86 emulator: emulate LAHF

Opcode 9F.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 5053e9efb140..90b549ed8997 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3227,6 +3227,13 @@ static int em_cpuid(struct x86_emulate_ctxt *ctxt)
         return X86EMUL_CONTINUE;
 }
 
+static int em_lahf(struct x86_emulate_ctxt *ctxt)
+{
+        ctxt->regs[VCPU_REGS_RAX] &= ~0xff00UL;
+        ctxt->regs[VCPU_REGS_RAX] |= (ctxt->eflags & 0xff) << 8;
+        return X86EMUL_CONTINUE;
+}
+
 static bool valid_cr(int nr)
 {
         switch (nr) {
@@ -3622,7 +3629,7 @@ static struct opcode opcode_table[256] = {
         D(DstAcc | SrcNone), I(ImplicitOps | SrcAcc, em_cwd),
         I(SrcImmFAddr | No64, em_call_far), N,
         II(ImplicitOps | Stack, em_pushf, pushf),
-        II(ImplicitOps | Stack, em_popf, popf), N, N,
+        II(ImplicitOps | Stack, em_popf, popf), N, I(ImplicitOps, em_lahf),
         /* 0xA0 - 0xA7 */
         I2bv(DstAcc | SrcMem | Mov | MemAbs, em_mov),
         I2bv(DstMem | SrcAcc | Mov | MemAbs | PageTable, em_mov),