From: Avi Kivity <avi@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Subject: [Qemu-devel] Re: [PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD
Date: Mon, 31 Jan 2011 18:30:12 +0200 [thread overview]
Message-ID: <4D46E394.9000908@redhat.com> (raw)
In-Reply-To: <4D46C7BF.6010809@siemens.com>
On 01/31/2011 04:31 PM, Jan Kiszka wrote:
> >>
> >> And how would you be kicked out of the select() call if it is waiting
> >> with a timeout? We only have a single thread here.
> >
> > If we use signalfd() (either kernel provided or thread+pipe), we kick
> > out of select by select()ing it (though I don't see how it works without
> > an iothread, since an fd can't stop a vcpu unless you enable SIGIO on
> > it, which is silly for signalfd)
> >
> > If you leave it as a naked signal, then it can break out of either
> > pselect() or vcpu.
> >
> > Since the goal is to drop !CONFIG_IOTHREAD, the first path seems better,
> > I just don't understand the problem with emulated signalfd().
> >
>
> With the emulated signalfd, there won't be any signal for the VCPU while
> in KVM_RUN.
>
I see it now - with a real signalfd, kvm unmasks the signal, and that
takes precedence over signalfd and exits the vcpu.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-01-31 16:30 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-27 13:09 [Qemu-devel] [PATCH 00/22] [uq/master] Patch queue, part II Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 01/22] Prevent abortion on multiple VCPU kicks Jan Kiszka
2011-01-31 9:44 ` [Qemu-devel] " Avi Kivity
2011-01-31 11:19 ` Jan Kiszka
2011-01-31 13:16 ` Avi Kivity
2011-01-27 13:09 ` [Qemu-devel] [PATCH 02/22] Stop current VCPU on synchronous reset requests Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 03/22] Process vmstop requests in IO thread Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 04/22] Leave inner main_loop faster on pending requests Jan Kiszka
2011-01-31 9:52 ` [Qemu-devel] " Avi Kivity
2011-01-31 11:22 ` Jan Kiszka
2011-01-31 13:17 ` Avi Kivity
2011-01-31 14:32 ` Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 05/22] kvm: Report proper error on GET_VCPU_MMAP_SIZE failures Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 06/22] kvm: Drop redundant kvm_enabled from kvm_cpu_thread_fn Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 07/22] kvm: Handle kvm_init_vcpu errors Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 08/22] kvm: Provide sigbus services arch-independently Jan Kiszka
2011-01-27 16:39 ` [Qemu-devel] " Paolo Bonzini
2011-01-30 14:51 ` Alexander Graf
2011-01-27 13:09 ` [Qemu-devel] [PATCH 09/22] Refactor signal setup functions in cpus.c Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 10/22] kvm: Set up signal mask also for !CONFIG_IOTHREAD Jan Kiszka
2011-01-28 8:08 ` [Qemu-devel] " Paolo Bonzini
2011-01-27 13:09 ` [Qemu-devel] [PATCH 11/22] kvm: Refactor qemu_kvm_eat_signals Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 12/22] kvm: Call qemu_kvm_eat_signals also under !CONFIG_IOTHREAD Jan Kiszka
2011-01-28 8:09 ` [Qemu-devel] " Paolo Bonzini
2011-02-01 12:38 ` Marcelo Tosatti
2011-02-01 12:49 ` Marcelo Tosatti
2011-02-01 13:21 ` Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 13/22] Set up signalfd " Jan Kiszka
2011-01-28 8:11 ` [Qemu-devel] " Paolo Bonzini
2011-01-27 13:09 ` [Qemu-devel] [PATCH 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD Jan Kiszka
2011-01-27 14:20 ` [Qemu-devel] [PATCH v2 " Jan Kiszka
2011-01-27 14:33 ` [Qemu-devel] [PATCH v3 " Jan Kiszka
2011-01-31 10:03 ` [Qemu-devel] " Avi Kivity
2011-01-31 11:27 ` Jan Kiszka
2011-01-31 12:13 ` Stefan Hajnoczi
2011-01-31 12:18 ` Jan Kiszka
2011-01-31 13:35 ` Stefan Hajnoczi
2011-01-31 13:22 ` Avi Kivity
2011-01-31 14:31 ` Jan Kiszka
2011-01-31 16:30 ` Avi Kivity [this message]
2011-02-01 12:47 ` [Qemu-devel] Re: [PATCH " Marcelo Tosatti
2011-02-01 13:32 ` Jan Kiszka
2011-02-01 13:48 ` Marcelo Tosatti
2011-02-01 13:58 ` Jan Kiszka
2011-02-01 14:10 ` Marcelo Tosatti
2011-02-01 14:21 ` Jan Kiszka
2011-02-01 14:37 ` Jan Kiszka
2011-02-01 14:45 ` Jan Kiszka
2011-01-27 13:09 ` [Qemu-devel] [PATCH 15/22] kvm: Add MCE signal support for !CONFIG_IOTHREAD Jan Kiszka
2011-01-27 13:10 ` [Qemu-devel] [PATCH 16/22] Introduce VCPU self-signaling service Jan Kiszka
2011-02-01 13:14 ` [Qemu-devel] " Marcelo Tosatti
2011-02-01 13:33 ` Jan Kiszka
2011-02-01 13:50 ` Marcelo Tosatti
2011-02-01 13:59 ` Jan Kiszka
2011-01-27 13:10 ` [Qemu-devel] [PATCH 17/22] kvm: Move irqchip event processing out of inner loop Jan Kiszka
2011-01-31 10:08 ` [Qemu-devel] " Avi Kivity
2011-01-31 11:36 ` Jan Kiszka
2011-01-31 13:04 ` Jan Kiszka
2011-01-31 15:40 ` Jan Kiszka
2011-01-31 16:38 ` Gleb Natapov
2011-01-31 16:41 ` Jan Kiszka
2011-01-31 16:45 ` Jan Kiszka
2011-01-31 16:50 ` Gleb Natapov
2011-01-31 16:52 ` Jan Kiszka
2011-01-31 16:56 ` Gleb Natapov
2011-01-31 18:06 ` [Qemu-devel] [PATCH v2 17&18/22] kvm: Unconditionally reenter kernel after IO exits Jan Kiszka
2011-01-27 13:10 ` [Qemu-devel] [PATCH 18/22] " Jan Kiszka
2011-01-27 13:10 ` [Qemu-devel] [PATCH 19/22] kvm: Remove static return code of kvm_handle_io Jan Kiszka
2011-01-27 13:10 ` [Qemu-devel] [PATCH 20/22] kvm: Leave kvm_cpu_exec directly after KVM_EXIT_SHUTDOWN Jan Kiszka
2011-01-27 13:10 ` [Qemu-devel] [PATCH 21/22] Refactor kvm&tcg function names in cpus.c Jan Kiszka
2011-01-27 13:10 ` [Qemu-devel] [PATCH 22/22] Fix a few coding style violations " Jan Kiszka
2011-01-31 10:12 ` [Qemu-devel] Re: [PATCH 00/22] [uq/master] Patch queue, part II Avi Kivity
2011-01-31 12:03 ` Jan Kiszka
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=4D46E394.9000908@redhat.com \
--to=avi@redhat.com \
--cc=jan.kiszka@siemens.com \
--cc=kvm@vger.kernel.org \
--cc=mtosatti@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=stefanha@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).