The check sits in switch() statement which itself can check
for opcode 0x90 far more efficiently.
On assembler level, this change simply eliminates the following
bit of code:
4c 8b a3 d8 00 00 00 mov 0xd8(%rbx),%r12
31 f6 xor %esi,%esi
48 89 df mov %rbx,%rdi
e8 32 8c ff ff callq 490 <reg_read>
48 8d 83 78 01 00 00 lea 0x178(%rbx),%rax
83 8b 70 01 00 00 01 orl $0x1,0x170(%rbx)
83 8b 74 01 00 00 01 orl $0x1,0x174(%rbx)
49 39 c4 cmp %rax,%r12
0f 84 88 fa ff ff je 7304 <x86_emulate_insn+0x204>
Signed-off-by: Denys Vlasenko <dvlas...@redhat.com>
CC: Paolo Bonzini <pbonz...@redhat.com>
CC: Avi Kivity <avi.kiv...@gmail.com>
---
arch/x86/kvm/emulate.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 2bc1e81..7e6e74a 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4544,9 +4544,9 @@ special_insn:
case 0x8d: /* lea r16/r32, m */
ctxt->dst.val = ctxt->src.addr.mem.ea;
break;
- case 0x90 ... 0x97: /* nop / xchg reg, rax */
- if (ctxt->dst.addr.reg == reg_rmw(ctxt, VCPU_REGS_RAX))
- break;
+ case 0x90: /* nop */
+ break;
+ case 0x91 ... 0x97: /* xchg reg, rax */
rc = em_xchg(ctxt);
break;
case 0x98: /* cbw/cwde/cdqe */
--
1.8.1.4
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
