From: Paolo Bonzini <pbonzini@redhat.com>
To: David Hildenbrand <dahi@linux.vnet.ibm.com>,
Alexander Graf <agraf@suse.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
KVM <kvm@vger.kernel.org>, qemu-devel <qemu-devel@nongnu.org>,
Cornelia Huck <cornelia.huck@de.ibm.com>,
Jens Freimann <jfrei@linux.vnet.ibm.com>,
linux-s390 <linux-s390@vger.kernel.org>
Subject: Re: [Qemu-devel] [PATCH/RFC 4/5] s390x/kvm: test whether a cpu is STOPPED when checking "has_work"
Date: Mon, 28 Jul 2014 16:19:35 +0200 [thread overview]
Message-ID: <53D65BF7.5060104@redhat.com> (raw)
In-Reply-To: <20140728161644.00c09b3f@thinkpad-w530>
Il 28/07/2014 16:16, David Hildenbrand ha scritto:
> Later, another vcpu might decide to turn that vcpu back on (by e.g. sending a
> SIGP START to that vcpu).
>
> I am not sure if such a mechanism/scenario is applicable to any other arch. They
> all seem to reset the cs->halted flag if they know they are able to run (e.g.
> due to an interrupt) - they have no such thing as "stopped cpus", only
> "halted/waiting cpus".
On x86, INIT_RECEIVED is pretty much a stopped CPU. It can only run
(and receive interrupts) after getting a special startup interrupt ("SIPI").
Paolo
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: David Hildenbrand <dahi@linux.vnet.ibm.com>,
Alexander Graf <agraf@suse.de>
Cc: linux-s390 <linux-s390@vger.kernel.org>,
KVM <kvm@vger.kernel.org>, qemu-devel <qemu-devel@nongnu.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Jens Freimann <jfrei@linux.vnet.ibm.com>,
Cornelia Huck <cornelia.huck@de.ibm.com>
Subject: Re: [Qemu-devel] [PATCH/RFC 4/5] s390x/kvm: test whether a cpu is STOPPED when checking "has_work"
Date: Mon, 28 Jul 2014 16:19:35 +0200 [thread overview]
Message-ID: <53D65BF7.5060104@redhat.com> (raw)
In-Reply-To: <20140728161644.00c09b3f@thinkpad-w530>
Il 28/07/2014 16:16, David Hildenbrand ha scritto:
> Later, another vcpu might decide to turn that vcpu back on (by e.g. sending a
> SIGP START to that vcpu).
>
> I am not sure if such a mechanism/scenario is applicable to any other arch. They
> all seem to reset the cs->halted flag if they know they are able to run (e.g.
> due to an interrupt) - they have no such thing as "stopped cpus", only
> "halted/waiting cpus".
On x86, INIT_RECEIVED is pretty much a stopped CPU. It can only run
(and receive interrupts) after getting a special startup interrupt ("SIPI").
Paolo
next prev parent reply other threads:[~2014-07-28 14:19 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-10 13:10 [PATCH/RFC 0/5] s390x/kvm: track the logical cpu state in QEMU and propagate it to kvm Christian Borntraeger
2014-07-10 13:10 ` [Qemu-devel] " Christian Borntraeger
2014-07-10 13:10 ` [PATCH/RFC 1/5] update linux headers with with cpustate changes Christian Borntraeger
2014-07-10 13:10 ` [Qemu-devel] " Christian Borntraeger
2014-07-10 13:10 ` [PATCH/RFC 2/5] s390x/kvm: introduce proper states for s390 cpus Christian Borntraeger
2014-07-10 13:10 ` [Qemu-devel] " Christian Borntraeger
2014-07-10 13:10 ` [PATCH/RFC 3/5] s390x/kvm: proper use of the cpu states OPERATING and STOPPED Christian Borntraeger
2014-07-10 13:10 ` [Qemu-devel] " Christian Borntraeger
2014-07-10 13:10 ` [PATCH/RFC 4/5] s390x/kvm: test whether a cpu is STOPPED when checking "has_work" Christian Borntraeger
2014-07-10 13:10 ` [Qemu-devel] " Christian Borntraeger
2014-07-28 13:49 ` Alexander Graf
2014-07-28 13:49 ` [Qemu-devel] " Alexander Graf
2014-07-28 14:16 ` David Hildenbrand
2014-07-28 14:16 ` David Hildenbrand
2014-07-28 14:19 ` Paolo Bonzini [this message]
2014-07-28 14:19 ` Paolo Bonzini
2014-07-28 14:22 ` Alexander Graf
2014-07-28 14:22 ` Alexander Graf
2014-07-28 15:03 ` David Hildenbrand
2014-07-28 15:03 ` David Hildenbrand
2014-07-28 15:57 ` David Hildenbrand
2014-07-28 15:57 ` David Hildenbrand
2014-07-28 16:45 ` Alexander Graf
2014-07-28 16:45 ` Alexander Graf
2014-07-29 13:52 ` Paolo Bonzini
2014-07-29 13:52 ` Paolo Bonzini
2014-07-29 15:06 ` David Hildenbrand
2014-07-29 15:06 ` David Hildenbrand
2014-07-29 11:44 ` Christian Borntraeger
2014-07-29 11:44 ` Christian Borntraeger
2014-07-29 11:44 ` Christian Borntraeger
2014-07-29 11:49 ` Alexander Graf
2014-07-29 11:49 ` Alexander Graf
2014-07-31 7:45 ` David Hildenbrand
2014-07-31 7:45 ` David Hildenbrand
2014-07-10 13:10 ` [PATCH/RFC 5/5] s390x/kvm: propagate s390 cpu state to kvm Christian Borntraeger
2014-07-10 13:10 ` [Qemu-devel] " Christian Borntraeger
2014-07-10 13:14 ` [PATCH/RFC 0/5] s390x/kvm: track the logical cpu state in QEMU and propagate it " David Hildenbrand
2014-07-10 13:14 ` [Qemu-devel] " David Hildenbrand
2014-07-10 13:14 ` David Hildenbrand
2014-07-10 13:14 ` [Qemu-devel] " David Hildenbrand
2014-07-10 13:27 ` David Hildenbrand
2014-07-10 13:27 ` [Qemu-devel] " David Hildenbrand
2014-07-28 13:43 ` Alexander Graf
2014-07-28 13:43 ` [Qemu-devel] " Alexander Graf
2014-07-28 13:45 ` Alexander Graf
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