From: Bandan Das <b...@redhat.com>
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 <b...@redhat.com>
[Fix immediate operands with rip-relative addressing. - Paolo]
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
arch/x86/include/asm/kvm_emulate.h | 5 +++++
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;
--
1.8.3.1
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