KVM: emulate: speed up emulated moves

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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>

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Paolo Bonzini 2014-03-27 11:36:25 +01:00

parent d40a6898e5

commit 54cfdb3e95

2 changed files with 2 additions and 2 deletions

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arch/x86/include/asm/kvm_emulate.h

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arch/x86/kvm/emulate.c

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