From: Avi Kivity <avi@redhat.com>
To: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Cc: mtosatti@redhat.com, kvm@vger.kernel.org,
yoshikawa.takuya@oss.ntt.co.jp, gleb@redhat.com
Subject: Re: [RFC PATCH 2/2] KVM: x86 emulator: Cleanup emulate_push() writebacks
Date: Sun, 03 Apr 2011 19:04:15 +0300 [thread overview]
Message-ID: <4D989A7F.8000700@redhat.com> (raw)
In-Reply-To: <20110404005907.0edba901.takuya.yoshikawa@gmail.com>
On 04/03/2011 06:59 PM, Takuya Yoshikawa wrote:
> > I think it's easier to just write directly instead of going through
> > 'struct operand'.
> >
> > Probably emulate_push() should do the write (look at segmented_write()
> > in my 'Emulator segment checks' patchset), and everything else can call
> > that. 'struct operand' is for multiplexing register/memory accesses,
> > which is not the case with the stack.
>
> I agree with you. I will update!
>
>
> IMHO, we are using dst operand for too many things.
>
> In the case of CMP, I first tried to use src2 to clearly follow the
> SDM's "second source operand" terminology. But it seemed not worth
> it now.
>
Ah, CMP is encoded as dst/src, so it's best to just disable writeback
there. We could have a bit in the decode tables to auto-disable
writeback, but not sure it is worth it.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-04-03 16:04 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-28 16:32 [PATCH 1/2] KVM: x86 emulator: Disable writeback for CMP emulation Takuya Yoshikawa
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 [this message]
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
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