diff options
| author | Bandan Das <bsd@redhat.com> | 2014-04-16 12:46:14 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-07-11 09:14:01 +0200 |
| commit | 41061cdb98a0bec464278b4db8e894a3121671f5 (patch) | |
| tree | da1cd3e8f52f23fe8dd614b38474065f5b9f3ca1 | |
| parent | 573e80fe04db1aa44e8303037f65716ba5c3a343 (diff) | |
KVM: emulate: do not initialize memopp
rip_relative is only set if decode_modrm runs, and if you have ModRM
you will also have a memopp. We can then access memopp unconditionally.
Note that rip_relative cannot be hoisted up to decode_modrm, or you
break "mov $0, xyz(%rip)".
Also, move typecast on "out of range value" of mem.ea to decode_modrm.
Together, all these optimizations save about 50 cycles on each emulated
instructions (4-6%).
Signed-off-by: Bandan Das <bsd@redhat.com>
[Fix immediate operands with rip-relative addressing. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/include/asm/kvm_emulate.h | 5 | ||||
| -rw-r--r-- | arch/x86/kvm/emulate.c | 8 |
2 files changed, 9 insertions, 4 deletions
diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index 6c808408326f..fcf58cd25ebd 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -295,6 +295,11 @@ struct x86_emulate_ctxt { struct operand dst; int (*execute)(struct x86_emulate_ctxt *ctxt); int (*check_perm)(struct x86_emulate_ctxt *ctxt); + /* + * The following six fields are cleared together, + * the rest are initialized unconditionally in x86_decode_insn + * or elsewhere + */ bool rip_relative; u8 rex_prefix; u8 lock_prefix; diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 08badf638fb0..390400a54a9c 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1177,6 +1177,9 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, } } op->addr.mem.ea = modrm_ea; + if (ctxt->ad_bytes != 8) + ctxt->memop.addr.mem.ea = (u32)ctxt->memop.addr.mem.ea; + done: return rc; } @@ -4425,9 +4428,6 @@ done_prefixes: ctxt->memop.addr.mem.seg = ctxt->seg_override; - if (ctxt->memop.type == OP_MEM && ctxt->ad_bytes != 8) - ctxt->memop.addr.mem.ea = (u32)ctxt->memop.addr.mem.ea; - /* * Decode and fetch the source operand: register, memory * or immediate. @@ -4448,7 +4448,7 @@ done_prefixes: rc = decode_operand(ctxt, &ctxt->dst, (ctxt->d >> DstShift) & OpMask); done: - if (ctxt->memopp && ctxt->memopp->type == OP_MEM && ctxt->rip_relative) + if (ctxt->rip_relative) ctxt->memopp->addr.mem.ea += ctxt->_eip; return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK; |