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>

1 files changed, 4 insertions, 4 deletions

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;