From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Peter Lieven <pl@dlhnet.de>
Cc: Gleb Natapov <gleb@redhat.com>, Jan Kiszka <jan.kiszka@web.de>,
qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: 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 16:51:52 +0800 [thread overview]
Message-ID: <4FF555A8.3000601@linux.vnet.ibm.com> (raw)
In-Reply-To: <4FEC1FC9.7050103@dlhnet.de>
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?
next prev parent reply other threads:[~2012-07-05 8:51 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-27 15:39 race between kvm-kmod-3.0 and kvm-kmod-3.3 // was: race condition in qemu-kvm-1.0.1 Peter Lieven
2012-06-27 16:54 ` Jan Kiszka
2012-06-28 9:11 ` Peter Lieven
2012-06-28 9:21 ` Jan Kiszka
2012-06-28 9:31 ` Peter Lieven
2012-06-28 9:38 ` Peter Lieven
2012-07-02 15:05 ` 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
2012-06-28 9:39 ` Jan Kiszka
2012-06-28 10:13 ` Peter Lieven
2012-06-28 10:34 ` Peter Lieven
2012-07-05 8:51 ` Xiao Guangrong [this message]
2012-07-05 12:42 ` Peter Lieven
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=4FF555A8.3000601@linux.vnet.ibm.com \
--to=xiaoguangrong@linux.vnet.ibm.com \
--cc=gleb@redhat.com \
--cc=jan.kiszka@web.de \
--cc=kvm@vger.kernel.org \
--cc=pl@dlhnet.de \
--cc=qemu-devel@nongnu.org \
/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).