From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org, Bandan Das <bsd@redhat.com>
Subject: [PATCH 13/19] KVM: emulate: do not initialize memopp
Date: Mon, 14 Jul 2014 13:38:37 +0200 [thread overview]
Message-ID: <1405337923-4776-14-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1405337923-4776-1-git-send-email-pbonzini@redhat.com>
From: Bandan Das <bsd@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 <bsd@redhat.com>
[Fix immediate operands with rip-relative addressing. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@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
next prev parent reply other threads:[~2014-07-14 11:39 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-14 11:38 [PATCH resend 00/19] Emulator speedups for 3.17 Paolo Bonzini
2014-07-14 11:38 ` [PATCH 01/19] KVM: vmx: speed up emulation of invalid guest state Paolo Bonzini
2014-07-14 11:38 ` [PATCH 02/19] KVM: x86: return all bits from get_interrupt_shadow Paolo Bonzini
2014-07-14 11:38 ` [PATCH 03/19] KVM: x86: avoid useless set of KVM_REQ_EVENT after emulation Paolo Bonzini
2014-07-14 11:38 ` [PATCH 04/19] KVM: emulate: move around some checks Paolo Bonzini
2014-07-14 11:38 ` [PATCH 05/19] KVM: emulate: protect checks on ctxt->d by a common "if (unlikely())" Paolo Bonzini
2014-07-14 11:38 ` [PATCH 06/19] KVM: emulate: speed up emulated moves Paolo Bonzini
2014-07-14 11:38 ` [PATCH 07/19] KVM: emulate: simplify writeback Paolo Bonzini
2014-07-14 11:38 ` [PATCH 08/19] KVM: emulate: move init_decode_cache to emulate.c Paolo Bonzini
2014-07-14 11:38 ` [PATCH 09/19] KVM: emulate: Remove ctxt->intercept and ctxt->check_perm checks Paolo Bonzini
2014-07-14 11:38 ` [PATCH 10/19] KVM: emulate: cleanup decode_modrm Paolo Bonzini
2014-07-14 11:38 ` [PATCH 11/19] KVM: emulate: clean up initializations in init_decode_cache Paolo Bonzini
2014-07-14 11:38 ` [PATCH 12/19] KVM: emulate: rework seg_override Paolo Bonzini
2014-07-14 11:38 ` Paolo Bonzini [this message]
2014-07-14 11:38 ` [PATCH 14/19] KVM: emulate: speed up do_insn_fetch Paolo Bonzini
2014-07-14 11:38 ` [PATCH 15/19] KVM: emulate: avoid repeated calls to do_insn_fetch_bytes Paolo Bonzini
2014-07-14 11:38 ` [PATCH 16/19] KVM: emulate: avoid per-byte copying in instruction fetches Paolo Bonzini
2014-07-14 11:38 ` [PATCH 17/19] KVM: emulate: put pointers in the fetch_cache Paolo Bonzini
2014-07-14 11:38 ` [PATCH 18/19] KVM: x86: ensure emulator fetches do not span multiple pages Paolo Bonzini
2014-07-14 11:38 ` [PATCH 19/19] KVM: x86: use kvm_read_guest_page for emulator accesses Paolo Bonzini
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