From: Gleb Natapov <gleb@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: aliguori@us.ibm.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, Liu Ping Fan <kernelfans@gmail.com>,
qemu-devel@nongnu.org, ryanh@us.ibm.com, jan.kiszka@web.de
Subject: Re: [Qemu-devel] [PATCH 2/2] kvm: exit to userspace with reason KVM_EXIT_VCPU_DEAD
Date: Sun, 27 Nov 2011 12:50:00 +0200 [thread overview]
Message-ID: <20111127105000.GL2557@redhat.com> (raw)
In-Reply-To: <4ED212C7.1080901@redhat.com>
On Sun, Nov 27, 2011 at 12:36:55PM +0200, Avi Kivity wrote:
> On 11/27/2011 04:42 AM, Liu Ping Fan wrote:
> > From: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
> >
> > The vcpu can be safely released when
> > --1.guest tells us that the vcpu is not needed any longer.
> > --2.vcpu hits the last instruction _halt_
> >
> > If both of the conditions are satisfied, kvm exits to userspace
> > with the reason vcpu dead. So the user thread can exit safely.
> >
> >
>
> Seems to be completely unnecessary. If you want to exit from the vcpu
> thread, send it a signal.
>
Also if guest "tells us that the vcpu is not needed any longer" (via
ACPI I presume) and vcpu actually doing something critical instead of
sitting in 1:hlt; jmp 1b loop then it is guest's problem if it stops
working after vcpu destruction.
--
Gleb.
next prev parent reply other threads:[~2011-11-27 10:50 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-25 2:35 [Qemu-devel] [PATCH 0] A series patches for kvm&qemu to enable vcpu destruction in kvm Liu Ping Fan
2011-11-25 2:35 ` [Qemu-devel] [PATCH 1/2] kvm: make vcpu life cycle separated from kvm instance Liu Ping Fan
2011-11-27 10:36 ` Avi Kivity
2011-11-25 17:54 ` [Qemu-devel] [PATCH 0] A series patches for kvm&qemu to enable vcpu destruction in kvm Jan Kiszka
2011-11-27 3:07 ` Liu ping fan
2011-11-27 2:42 ` [Qemu-devel] [PATCH 2/2] kvm: exit to userspace with reason KVM_EXIT_VCPU_DEAD Liu Ping Fan
2011-11-27 10:36 ` Avi Kivity
2011-11-27 10:50 ` Gleb Natapov [this message]
2011-11-28 7:16 ` Liu ping fan
2011-11-28 8:46 ` Gleb Natapov
2011-11-27 2:45 ` [Qemu-devel] [PATCH 1/5] QEMU Add cpu_phyid_to_cpu() to map cpu phyid to CPUState Liu Ping Fan
2011-11-27 2:45 ` [Qemu-devel] [PATCH 2/5] QEMU Add cpu_free() to support arch related CPUState release Liu Ping Fan
2011-11-27 2:45 ` [Qemu-devel] [PATCH 3/5] QEMU Introduce a pci device "cpustate" to get CPU_DEAD event in guest Liu Ping Fan
2011-11-27 10:56 ` Gleb Natapov
2011-11-27 2:45 ` [Qemu-devel] [PATCH 4/5] QEMU Release vcpu and finally exit vcpu thread safely Liu Ping Fan
2011-11-29 5:37 ` ShaoHe Feng
2011-11-27 2:45 ` [Qemu-devel] [PATCH 5/5] QEMU tmp patches for linux-header files Liu Ping Fan
2011-11-27 2:47 ` [Qemu-devel] [PATCH] virtio: add a pci driver to notify host the CPU_DEAD event Liu Ping Fan
2011-11-27 11:10 ` Gleb Natapov
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