From: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
To: avi@redhat.com, mtosatti@redhat.com
Cc: kvm@vger.kernel.org, yoshikawa.takuya@oss.ntt.co.jp, gleb@redhat.com
Subject: [PATCH 1/2] KVM: x86 emulator: Disable writeback for CMP emulation
Date: Tue, 29 Mar 2011 01:32:29 +0900 [thread overview]
Message-ID: <20110329013229.20e6168f.takuya.yoshikawa@gmail.com> (raw)
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
This stops "CMP r/m, reg" to write back the data into memory.
Pointed out by Avi.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
---
arch/x86/kvm/emulate.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 14c5ad5..8a73805 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3084,6 +3084,7 @@ special_insn:
emulate_2op_SrcV("xor", c->src, c->dst, ctxt->eflags);
break;
case 0x38 ... 0x3d:
+ c->dst.type = OP_NONE; /* Disable writeback. */
cmp: /* cmp */
emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
break;
@@ -3138,6 +3139,7 @@ special_insn:
case 6:
goto xor;
case 7:
+ c->dst.type = OP_NONE; /* Disable writeback. */
goto cmp;
}
break;
--
1.7.1
next reply other threads:[~2011-03-28 16:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-28 16:32 Takuya Yoshikawa [this message]
2011-03-28 16:34 ` [RFC PATCH 2/2] KVM: x86 emulator: Cleanup emulate_push() writebacks Takuya Yoshikawa
2011-03-30 6:51 ` Takuya Yoshikawa
2011-04-03 14:50 ` Avi Kivity
2011-04-03 15:59 ` Takuya Yoshikawa
2011-04-03 16:04 ` Avi Kivity
2011-04-03 16:09 ` Takuya Yoshikawa
2011-04-03 16:11 ` Avi Kivity
2011-04-03 14:42 ` [PATCH 1/2] KVM: x86 emulator: Disable writeback for CMP emulation Avi Kivity
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110329013229.20e6168f.takuya.yoshikawa@gmail.com \
--to=takuya.yoshikawa@gmail.com \
--cc=avi@redhat.com \
--cc=gleb@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=mtosatti@redhat.com \
--cc=yoshikawa.takuya@oss.ntt.co.jp \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox