From: Avi Kivity <avi@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Liu Ping Fan <pingfank@linux.vnet.ibm.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
liu ping fan <qemulist@gmail.com>,
Anthony Liguori <anthony@codemonkey.ws>,
Stefan Hajnoczi <stefanha@gmail.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [patch v4 13/16] e1000: add busy flag to anti broken device state
Date: Thu, 25 Oct 2012 11:04:07 +0200 [thread overview]
Message-ID: <50890087.1080706@redhat.com> (raw)
In-Reply-To: <CAFEAcA_rXqKDXjyHe3ap8oYonOdP-2dFS8V6Cos+NnBxBvQcbg@mail.gmail.com>
On 10/25/2012 11:00 AM, Peter Maydell wrote:
> On 23 October 2012 10:37, Avi Kivity <avi@redhat.com> wrote:
>> On 10/23/2012 11:32 AM, liu ping fan wrote:
>>> On Tue, Oct 23, 2012 at 5:07 PM, Jan Kiszka <jan.kiszka@siemens.com> wrote:
>>>> On 2012-10-23 07:52, liu ping fan wrote:
>>>>> On Mon, Oct 22, 2012 at 6:40 PM, Avi Kivity <avi@redhat.com> wrote:
>>>>>> On 10/22/2012 11:23 AM, Liu Ping Fan wrote:
>>>>> It will only record and fix the issue on one thread. But guest can
>>>>> touch the emulated device on muti-threads.
>>>>
>>>> Sorry, what does that mean? A second VCPU accessing the device will
>>>> simply be ignored when it races with another VCPU? Specifically
>>>>
>>> Yes, just ignored. For device which support many logic in parallel,
>>> it should use independent busy flag for each logic
>>
>> We don't actually know that e1000 doesn't. Why won't writing into
>> different registers in parallel work?
>
> Unless the device we're emulating supports multiple in
> parallel accesses (and I bet 99.9% of the devices we model
> don't) then the memory framework needs to serialise the
> loads/stores. Otherwise it's just going to be excessively
> hard to write a reliable device model.
That's why we have a per-device lock. The busy flag breaks that model
by discarding accesses that occur in parallel.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-10-25 9:04 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-22 9:23 [Qemu-devel] [patch v4 00/16] push mmio dispatch out of big lock Liu Ping Fan
2012-10-22 9:23 ` [Qemu-devel] [patch v4 01/16] atomic: introduce atomic operations Liu Ping Fan
2012-10-22 9:23 ` [Qemu-devel] [patch v4 02/16] qom: apply atomic on object's refcount Liu Ping Fan
2012-10-22 9:23 ` [Qemu-devel] [patch v4 03/16] hotplug: introduce qdev_unplug_complete() to remove device from views Liu Ping Fan
2012-10-22 9:23 ` [Qemu-devel] [patch v4 04/16] pci: remove pci device from mem view when unplug Liu Ping Fan
2012-10-22 9:23 ` [Qemu-devel] [patch v4 05/16] memory: introduce ref, unref interface for MemoryRegionOps Liu Ping Fan
2012-10-22 9:38 ` Avi Kivity
2012-10-23 11:51 ` Paolo Bonzini
2012-10-23 11:55 ` Avi Kivity
2012-10-23 11:57 ` Paolo Bonzini
2012-10-23 12:02 ` Avi Kivity
2012-10-23 12:06 ` Paolo Bonzini
2012-10-23 12:15 ` Avi Kivity
2012-10-23 12:32 ` Paolo Bonzini
2012-10-23 14:49 ` Avi Kivity
2012-10-23 15:26 ` Paolo Bonzini
2012-10-23 16:09 ` Avi Kivity
2012-10-24 7:29 ` Paolo Bonzini
2012-10-25 16:28 ` Avi Kivity
2012-10-26 15:05 ` Paolo Bonzini
2012-10-23 12:04 ` Jan Kiszka
2012-10-23 12:12 ` Paolo Bonzini
2012-10-23 12:16 ` Jan Kiszka
2012-10-23 12:28 ` Avi Kivity
2012-10-23 12:40 ` Jan Kiszka
2012-10-23 14:37 ` Avi Kivity
2012-10-22 9:23 ` [Qemu-devel] [patch v4 06/16] memory: document ref, unref interface Liu Ping Fan
2012-10-22 9:23 ` [Qemu-devel] [patch v4 07/16] memory: make mmio dispatch able to be out of biglock Liu Ping Fan
2012-10-23 12:12 ` Jan Kiszka
2012-10-23 12:36 ` Avi Kivity
2012-10-24 6:31 ` liu ping fan
2012-10-24 6:56 ` liu ping fan
2012-10-25 8:57 ` Avi Kivity
2012-10-22 9:23 ` [Qemu-devel] [patch v4 08/16] QemuThread: make QemuThread as tls to store extra info Liu Ping Fan
2012-10-22 9:30 ` Jan Kiszka
2012-10-22 17:13 ` Peter Maydell
2012-10-23 5:58 ` liu ping fan
2012-10-23 11:48 ` Paolo Bonzini
2012-10-23 11:50 ` Peter Maydell
2012-10-23 11:51 ` Jan Kiszka
2012-10-23 12:00 ` Paolo Bonzini
2012-10-23 12:27 ` Peter Maydell
2012-11-18 10:02 ` Brad Smith
2012-11-18 16:14 ` Paolo Bonzini
2012-11-18 16:15 ` Paolo Bonzini
2012-10-22 9:23 ` [Qemu-devel] [patch v4 09/16] memory: introduce mmio request pending to anti nested DMA Liu Ping Fan
2012-10-22 10:28 ` Avi Kivity
2012-10-23 12:38 ` Gleb Natapov
2012-10-24 6:31 ` liu ping fan
2012-10-22 9:23 ` [Qemu-devel] [patch v4 10/16] memory: introduce lock ops for MemoryRegionOps Liu Ping Fan
2012-10-22 10:30 ` Avi Kivity
2012-10-23 5:53 ` liu ping fan
2012-10-23 8:53 ` Jan Kiszka
2012-10-22 9:23 ` [Qemu-devel] [patch v4 11/16] vcpu: push mmio dispatcher out of big lock Liu Ping Fan
2012-10-22 10:31 ` Avi Kivity
2012-10-22 10:36 ` Jan Kiszka
2012-10-22 9:23 ` [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000 Liu Ping Fan
2012-10-22 10:37 ` Avi Kivity
2012-10-23 9:04 ` Jan Kiszka
2012-10-24 6:31 ` liu ping fan
2012-10-24 7:17 ` Jan Kiszka
2012-10-25 9:01 ` Avi Kivity
2012-10-25 9:31 ` Jan Kiszka
2012-10-25 16:21 ` Avi Kivity
2012-10-25 16:39 ` Jan Kiszka
2012-10-25 17:02 ` Avi Kivity
2012-10-25 18:48 ` Jan Kiszka
2012-10-29 5:24 ` liu ping fan
2012-10-24 7:29 ` liu ping fan
2012-10-25 13:34 ` Jan Kiszka
2012-10-25 16:23 ` Avi Kivity
2012-10-25 16:41 ` Jan Kiszka
2012-10-25 17:03 ` Avi Kivity
2012-10-29 5:24 ` liu ping fan
2012-10-31 7:03 ` Jan Kiszka
2012-10-22 9:23 ` [Qemu-devel] [patch v4 13/16] e1000: add busy flag to anti broken device state Liu Ping Fan
2012-10-22 10:40 ` Avi Kivity
2012-10-23 5:52 ` liu ping fan
2012-10-23 9:06 ` Avi Kivity
2012-10-23 9:07 ` Jan Kiszka
2012-10-23 9:32 ` liu ping fan
2012-10-23 9:37 ` Avi Kivity
2012-10-24 6:36 ` liu ping fan
2012-10-25 8:55 ` Avi Kivity
2012-10-25 9:00 ` Peter Maydell
2012-10-25 9:04 ` Avi Kivity [this message]
2012-10-26 3:05 ` liu ping fan
2012-10-26 3:08 ` liu ping fan
2012-10-26 10:25 ` Jan Kiszka
2012-10-29 5:24 ` liu ping fan
2012-10-29 7:50 ` Peter Maydell
2012-10-22 9:23 ` [Qemu-devel] [patch v4 14/16] qdev: introduce stopping state Liu Ping Fan
2012-10-22 9:23 ` [Qemu-devel] [patch v4 15/16] e1000: introduce unmap() to fix unplug issue Liu Ping Fan
2012-10-22 9:23 ` [Qemu-devel] [patch v4 16/16] e1000: implement MemoryRegionOps's ref&lock interface Liu Ping Fan
2012-10-25 14:04 ` [Qemu-devel] [patch v4 00/16] push mmio dispatch out of big lock Peter Maydell
2012-10-25 16:44 ` Jan Kiszka
2012-10-25 17:07 ` Avi Kivity
2012-10-25 17:13 ` Peter Maydell
2012-10-25 18:13 ` Marcelo Tosatti
2012-10-25 19:00 ` Jan Kiszka
2012-10-25 19:06 ` Peter Maydell
2012-10-29 15:24 ` 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=50890087.1080706@redhat.com \
--to=avi@redhat.com \
--cc=anthony@codemonkey.ws \
--cc=jan.kiszka@siemens.com \
--cc=mtosatti@redhat.com \
--cc=pbonzini@redhat.com \
--cc=peter.maydell@linaro.org \
--cc=pingfank@linux.vnet.ibm.com \
--cc=qemu-devel@nongnu.org \
--cc=qemulist@gmail.com \
--cc=stefanha@gmail.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).