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From: Avi Kivity <avi@redhat.com>
To: Jan Kiszka <jan.kiszka@web.de>
Cc: Liu Ping Fan <pingfank@linux.vnet.ibm.com>,
	kvm <kvm@vger.kernel.org>, Marcelo Tosatti <mtosatti@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>,
	Alexander Graf <agraf@suse.de>,
	Anthony Liguori <anthony@codemonkey.ws>
Subject: Re: [Qemu-devel] [PATCH] kvm: First step to push iothread lock out of inner run loop
Date: Sun, 24 Jun 2012 11:49:42 +0300	[thread overview]
Message-ID: <4FE6D4A6.9080708@redhat.com> (raw)
In-Reply-To: <4FE5AC75.1020504@web.de>

On 06/23/2012 02:45 PM, Jan Kiszka wrote:
> 
> Hmm, we may need the iothread lock around cpu_set_apic_tpr for
> !kvm_irqchip_in_kernel(). And as we are at it, apic_base manipulation
> can be but there as well.
> 
> With in-kernel irqchip, there is no such need. Also, no one accesses
> eflags outside of the vcpu thread, independent of the irqchip mode.

In fact !kvm_irqchip_in_kernel() is broken wrt the tpr.  Interrupt
injection needs to be done atomically, but currently we check the tpr
from the injecting thread, which means the cpu thread can race with it.
 We need to move the check to the vcpu thread so that the guest vcpu is
halted.


-- 
error compiling committee.c: too many arguments to function

  reply	other threads:[~2012-06-24  8:49 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-22 22:45 [Qemu-devel] [PATCH] kvm: First step to push iothread lock out of inner run loop Jan Kiszka
2012-06-22 22:55 ` Jan Kiszka
2012-06-23  0:22   ` Marcelo Tosatti
2012-06-23  9:06     ` Marcelo Tosatti
2012-06-23 11:45       ` Jan Kiszka
2012-06-24  8:49         ` Avi Kivity [this message]
2012-06-24 14:08           ` Jan Kiszka
2012-06-24 14:31             ` Avi Kivity
2012-07-06 17:16             ` Jan Kiszka
2012-07-06 18:06               ` Jan Kiszka
2012-07-08  7:49                 ` Avi Kivity
2012-06-24 13:34         ` liu ping fan
2012-06-24 14:08           ` Jan Kiszka
2012-06-24 14:35             ` Avi Kivity
2012-06-24 14:40               ` Jan Kiszka
2012-06-24 14:46                 ` Avi Kivity
2012-06-24 14:51                   ` Jan Kiszka
2012-06-24 14:56                     ` Avi Kivity
2012-06-24 14:58                       ` Jan Kiszka
2012-06-24 14:59                         ` Avi Kivity
2012-06-23  9:22     ` Jan Kiszka
2012-06-22 22:59 ` Anthony Liguori
2012-06-23  9:11   ` Jan Kiszka

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