From: Avi Kivity <avi@redhat.com>
To: ya su <suya94335@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
"Dong, Eddie" <eddie.dong@intel.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH] KVM: APIC: avoid instruction emulation for EOI writes
Date: Sun, 11 Sep 2011 10:11:16 +0300 [thread overview]
Message-ID: <4E6C5F14.1030407@redhat.com> (raw)
In-Reply-To: <CA+tHM2F8gTovWVLebc9T3GbbGmFjk50sqtQVU7vwZ-sHEUmzFA@mail.gmail.com>
On 09/10/2011 11:41 AM, ya su wrote:
> 0x80637b85: testl $0x1000, 0xfffe0300
> 0x80637b8f: jne 0x80637b85
> 0x80637b91: mov %ecx, 0xfffe0300
> 0x80637b97: testl $0x1000, 0xfffe0300
> 0x80637ba1: jne 0x80637b97
>
> I wonder why testl operation will also cause a ICR write, from the
> asm code, there should only issue one IPI, but from trace-cmd, it
> issued 3 IPI, is there something wrong?
It's a bug in test insn emulation, coincidentally I wrote a patch to fix
it yesterday, not imagining that it actually happens in practice.
> Is it also possible to optimize ICR write emulation, from the
> result, winxp vm will produce a lot of ICR writes
>
Unfortunately not.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2011-09-11 7:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-29 6:09 [PATCH] KVM: APIC: avoid instruction emulation for EOI writes Tian, Kevin
2011-08-29 7:23 ` Avi Kivity
2011-08-29 7:35 ` Tian, Kevin
2011-08-29 8:15 ` Sasha Levin
2011-08-29 8:51 ` Avi Kivity
2011-08-29 10:24 ` Jan Kiszka
2011-08-29 10:59 ` Avi Kivity
2011-08-29 11:03 ` Jan Kiszka
2011-08-29 11:11 ` Avi Kivity
2011-08-29 13:55 ` Jan Kiszka
2011-08-29 14:14 ` Avi Kivity
2011-09-10 8:41 ` ya su
2011-09-11 7:11 ` Avi Kivity [this message]
2011-09-11 8:05 ` Jan Kiszka
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