From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: KVM <kvm@vger.kernel.org>, Gleb Natapov <gleb@kernel.org>,
Rik van Riel <riel@redhat.com>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
Michael Mueller <mimu@linux.vnet.ibm.com>
Subject: Re: [PATCH/RFC] KVM: track pid for VCPU only on KVM_RUN ioctl
Date: Tue, 19 Aug 2014 11:47:33 +0200 [thread overview]
Message-ID: <53F31D35.4010901@de.ibm.com> (raw)
In-Reply-To: <53F3187E.6080706@redhat.com>
On 19/08/14 11:27, Paolo Bonzini wrote:
> Il 19/08/2014 10:38, Christian Borntraeger ha scritto:
>>>> The patch may be okay, but I'm worried that it might be hiding a bug in
>>>> QEMU.
>> On s390 we call "KVM_S390_INITIAL_RESET" from several reset functions, e.g. during
>> CPU creation. This is the first hickup and the pid now points to the main thread.
>
> Any reason to have a special ioctl instead of SET_REGS/SET_ONE_REG/...
> (via kvm_cpu_synchronize_state, which does the ioctls in the VCPU thread)?
Historical reasons mostly. Older kernel miss several interfaces to bring the CPU in a defined state (pending interrupts, cpu state, some registers...)
Good news is that we are working on getting rid of it: cpu states are now available as far as I can see, only local interrupt flushing is missing.This needs some more work on our side. So in some month we probably will have a QEMU version that does not need to call this any more. For todays QEMU this patch help though.
Christian
next prev parent reply other threads:[~2014-08-19 9:47 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-05 14:44 [PATCH/RFC] KVM: track pid for VCPU only on KVM_RUN ioctl Christian Borntraeger
2014-08-07 8:21 ` Raghavendra K T
2014-08-07 9:59 ` Christian Borntraeger
2014-08-07 13:40 ` Paolo Bonzini
2014-08-19 8:38 ` Christian Borntraeger
2014-08-07 13:39 ` Paolo Bonzini
2014-08-19 8:38 ` Christian Borntraeger
2014-08-19 9:27 ` Paolo Bonzini
2014-08-19 9:47 ` Christian Borntraeger [this message]
2014-08-19 9:53 ` Paolo Bonzini
2014-08-19 9:59 ` Christian Borntraeger
2014-08-19 10:03 ` Paolo Bonzini
2014-08-19 10:09 ` Christian Borntraeger
2014-08-19 10:31 ` Paolo Bonzini
2014-08-19 10:48 ` Christian Borntraeger
2014-08-19 10:50 ` Paolo Bonzini
2014-08-19 11:28 ` David Hildenbrand
2014-08-19 12:06 ` Paolo Bonzini
2014-08-19 12:14 ` David Hildenbrand
2014-08-19 14:10 ` Christian Borntraeger
2014-08-19 14:23 ` David Hildenbrand
2014-08-19 14:46 ` Christian Borntraeger
2014-08-19 14:52 ` David Hildenbrand
2014-08-18 5:02 ` Wanpeng Li
2014-08-19 14:04 ` Christian Borntraeger
2014-08-19 23:22 ` Wanpeng Li
2014-08-20 7:01 ` Christian Borntraeger
2014-12-03 13:20 ` Paolo Bonzini
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