From: Peter Lieven <pl@dlhnet.de>
To: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@redhat.com>, Jan Kiszka <jan.kiszka@web.de>,
qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [Qemu-devel] race between kvm-kmod-3.0 and kvm-kmod-3.3 // was: race condition in qemu-kvm-1.0.1
Date: Thu, 05 Jul 2012 14:42:42 +0200 [thread overview]
Message-ID: <4FF58BC2.3090303@dlhnet.de> (raw)
In-Reply-To: <4FF555A8.3000601@linux.vnet.ibm.com>
On 05.07.2012 10:51, Xiao Guangrong wrote:
> On 06/28/2012 05:11 PM, Peter Lieven wrote:
>
>> that here is bascially whats going on:
>>
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_mmio: mmio read len 3 gpa 0xa0000 val 0x10ff
>> qemu-kvm-1.0-2506 [010] 60996.908000: vcpu_match_mmio: gva 0xa0000 gpa 0xa0000 Read GPA
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_mmio: mmio unsatisfied-read len 1 gpa 0xa0000 val 0x0
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_userspace_exit: reason KVM_EXIT_MMIO (6)
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_mmio: mmio read len 3 gpa 0xa0000 val 0x10ff
>> qemu-kvm-1.0-2506 [010] 60996.908000: vcpu_match_mmio: gva 0xa0000 gpa 0xa0000 Read GPA
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_mmio: mmio unsatisfied-read len 1 gpa 0xa0000 val 0x0
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_userspace_exit: reason KVM_EXIT_MMIO (6)
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_mmio: mmio read len 3 gpa 0xa0000 val 0x10ff
>> qemu-kvm-1.0-2506 [010] 60996.908000: vcpu_match_mmio: gva 0xa0000 gpa 0xa0000 Read GPA
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_mmio: mmio unsatisfied-read len 1 gpa 0xa0000 val 0x0
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_userspace_exit: reason KVM_EXIT_MMIO (6)
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_mmio: mmio read len 3 gpa 0xa0000 val 0x10ff
>> qemu-kvm-1.0-2506 [010] 60996.908000: vcpu_match_mmio: gva 0xa0000 gpa 0xa0000 Read GPA
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_mmio: mmio unsatisfied-read len 1 gpa 0xa0000 val 0x0
>> qemu-kvm-1.0-2506 [010] 60996.908000: kvm_userspace_exit: reason KVM_EXIT_MMIO (6)
>>
> There are two mmio emulation after user-space-exit, it is caused by mmio
> read access which spans two pages. But it should be fixed by:
>
> commit f78146b0f9230765c6315b2e14f56112513389ad
> Author: Avi Kivity<avi@redhat.com>
> Date: Wed Apr 18 19:22:47 2012 +0300
>
> KVM: Fix page-crossing MMIO
>
> MMIO that are split across a page boundary are currently broken - the
> code does not expect to be aborted by the exit to userspace for the
> first MMIO fragment.
>
> This patch fixes the problem by generalizing the current code for handling
> 16-byte MMIOs to handle a number of "fragments", and changes the MMIO
> code to create those fragments.
>
> Signed-off-by: Avi Kivity<avi@redhat.com>
> Signed-off-by: Marcelo Tosatti<mtosatti@redhat.com>
>
> Could you please pull the code from:
> https://git.kernel.org/pub/scm/virt/kvm/kvm.git
> and trace it again?
Thank you very much, this fixes the issue I have seen.
Thanks,
Peter
prev parent reply other threads:[~2012-07-05 12:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4FEB2945.1030607@dlhnet.de>
[not found] ` <4FEB3AC6.6010206@web.de>
[not found] ` <4FEC1FC9.7050103@dlhnet.de>
[not found] ` <4FEC2210.1030005@siemens.com>
[not found] ` <4FEC2475.4030202@dlhnet.de>
[not found] ` <4FEC2626.90402@dlhnet.de>
2012-07-02 15:05 ` [Qemu-devel] race between kvm-kmod-3.0 and kvm-kmod-3.3 // was: race condition in qemu-kvm-1.0.1 Avi Kivity
2012-07-02 15:57 ` Peter Lieven
2012-07-03 13:01 ` Peter Lieven
2012-07-03 13:13 ` Avi Kivity
2012-07-03 13:15 ` Peter Lieven
2012-07-03 13:25 ` Avi Kivity
2012-07-04 14:57 ` Peter Lieven
2012-07-04 23:12 ` Peter Lieven
2012-07-05 6:48 ` Xiao Guangrong
2012-07-05 8:51 ` Xiao Guangrong
2012-07-05 12:42 ` Peter Lieven [this message]
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=4FF58BC2.3090303@dlhnet.de \
--to=pl@dlhnet.de \
--cc=gleb@redhat.com \
--cc=jan.kiszka@web.de \
--cc=kvm@vger.kernel.org \
--cc=qemu-devel@nongnu.org \
--cc=xiaoguangrong@linux.vnet.ibm.com \
/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;
as well as URLs for NNTP newsgroup(s).