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| author | Paolo Bonzini <pbonzini@redhat.com> | 2014-03-27 14:36:25 +0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-07-11 11:13:58 +0400 |
| commit | 54cfdb3e95d4f70409a7d3432a42cffc9a232be7 (patch) | |
| tree | 01ad8c40d9c316b7359fb7e7605ba0c9b85a75eb /arch/x86/kvm/emulate.c | |
| parent | d40a6898e50c2589ca3d345ef5ca6671e2b35b1a (diff) | |
| download | linux-54cfdb3e95d4f70409a7d3432a42cffc9a232be7.tar.xz | |
KVM: emulate: speed up emulated moves
We can just blindly move all 16 bytes of ctxt->src's value to ctxt->dst.
write_register_operand will take care of writing only the lower bytes.
Avoiding a call to memcpy (the compiler optimizes it out) gains about
200 cycles on kvm-unit-tests for register-to-register moves, and makes
them about as fast as arithmetic instructions.
We could perhaps get a larger speedup by moving all instructions _except_
moves out of x86_emulate_insn, removing opcode_len, and replacing the
switch statement with an inlined em_mov.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/emulate.c')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index ea56dae3e67c..27f677ef703e 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2990,7 +2990,7 @@ static int em_rdpmc(struct x86_emulate_ctxt *ctxt) static int em_mov(struct x86_emulate_ctxt *ctxt) { - memcpy(ctxt->dst.valptr, ctxt->src.valptr, ctxt->op_bytes); + memcpy(ctxt->dst.valptr, ctxt->src.valptr, sizeof(ctxt->src.valptr)); return X86EMUL_CONTINUE; } |