From: Gleb Natapov <gleb@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: "Zhang, Yang Z" <yang.z.zhang@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Shan, Haitao" <haitao.shan@intel.com>,
"Zhang, Xiantao" <xiantao.zhang@intel.com>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
"Anvin, H Peter" <h.peter.anvin@intel.com>
Subject: Re: [PATCH 2/2] x86, apicv: Add Posted Interrupt supporting
Date: Thu, 31 Jan 2013 11:43:48 +0200 [thread overview]
Message-ID: <20130131094348.GN15004@redhat.com> (raw)
In-Reply-To: <20130130230311.GA19081@amt.cnet>
On Wed, Jan 30, 2013 at 09:03:11PM -0200, Marcelo Tosatti wrote:
> Posted interrupt patch:
> 2) Must move IN_GUEST_MODE assignment after local_irq_disable, in
> vcpu_enter_guest function. Otherwise:
>
> cpu0 vcpu1<->cpu1
>
> vcpu->mode = IN_GUEST_MODE
>
> if IN_GUEST_MODE == true
> send IPI
> local_irq_disable
>
> PIR not transferred to VIRR, misses interrupt.
>
cpu0 will set KVM_REQ_EVENT, so vmentry will be aborted after
local_irq_disable() by ->requests check.
> 3) Must check outstanding PIR notification bit unconditionally on
> every VM-entry, because:
>
> 1. local_irq_disable
> 2. vcpu->mode = IN_GUEST_MODE
> 3. vmenter
> 4. vmexit
> 5. vcpu->mode = OUTSIDE_GUEST_MODE
>
> If PIR-IPI-interrupt is sent between an event which triggers VM-exit
> (for example, an external interrupt due to a device), and step 5
> (assignment of vcpu->mode), the PIR->VIRR transfer before vmentry must
> be made.
Not sure I understand, but I think KVM_REQ_EVENT will cover that too.
>
> 4) Today, an interrupt notification is cached on IRR until its delivered - further
> interrupt injection is not generating further interrupt notification
> bits. With PIR, behaviour changes: Its possible to have one bit in PIR and another
> on IRR APIC page (if timing is right). Is this harmless? Why?
>
>
--
Gleb.
next prev parent reply other threads:[~2013-01-31 9:43 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-13 7:29 [PATCH 0/2] KVM: Add posted interrupt supporting Yang Zhang
2012-12-13 7:29 ` [PATCH 1/2] x86: Enable ack interrupt on vmexit Yang Zhang
2012-12-13 7:51 ` Gleb Natapov
2012-12-13 7:54 ` Zhang, Yang Z
2012-12-13 7:58 ` Gleb Natapov
2012-12-13 8:03 ` Zhang, Yang Z
2012-12-13 8:05 ` Gleb Natapov
2012-12-13 8:19 ` Zhang, Yang Z
2012-12-13 8:22 ` Gleb Natapov
2012-12-13 8:23 ` Zhang, Yang Z
2012-12-16 13:26 ` Zhang, Yang Z
2012-12-18 9:11 ` Gleb Natapov
2012-12-13 7:29 ` [PATCH 2/2] x86, apicv: Add Posted Interrupt supporting Yang Zhang
2013-01-22 22:59 ` Marcelo Tosatti
2013-01-23 5:09 ` Zhang, Yang Z
2013-01-24 23:43 ` Marcelo Tosatti
2013-01-25 0:40 ` Zhang, Yang Z
2013-01-30 23:03 ` Marcelo Tosatti
2013-01-30 23:57 ` Marcelo Tosatti
2013-01-31 7:35 ` Gleb Natapov
2013-01-31 9:43 ` Gleb Natapov [this message]
2013-01-31 13:32 ` Marcelo Tosatti
2013-01-31 13:38 ` Gleb Natapov
2013-01-31 13:44 ` Marcelo Tosatti
2013-01-31 13:55 ` Gleb Natapov
2013-02-04 0:57 ` Marcelo Tosatti
2013-02-04 9:10 ` Zhang, Yang Z
2013-02-04 9:55 ` Gleb Natapov
2013-02-04 14:43 ` Marcelo Tosatti
2013-02-04 17:13 ` Gleb Natapov
2013-02-04 19:59 ` Marcelo Tosatti
2013-02-04 20:47 ` Marcelo Tosatti
2013-02-05 5:57 ` Zhang, Yang Z
2013-02-05 8:00 ` Gleb Natapov
2013-02-05 10:35 ` Zhang, Yang Z
2013-02-05 10:54 ` Gleb Natapov
2013-02-05 10:58 ` Zhang, Yang Z
2013-02-05 11:16 ` Gleb Natapov
2013-02-05 13:26 ` Zhang, Yang Z
2013-02-05 13:29 ` Gleb Natapov
2013-02-05 13:40 ` Zhang, Yang Z
2013-02-05 13:43 ` Gleb Natapov
2013-02-07 1:23 ` Marcelo Tosatti
2013-02-05 7:32 ` Gleb Natapov
2013-02-06 22:49 ` Marcelo Tosatti
2013-02-07 0:24 ` Marcelo Tosatti
2013-02-07 13:52 ` Gleb Natapov
2013-02-08 2:07 ` Marcelo Tosatti
2013-02-08 12:18 ` Gleb Natapov
2013-02-07 14:01 ` Gleb Natapov
2013-02-07 21:49 ` Marcelo Tosatti
2013-02-08 12:28 ` Gleb Natapov
2013-02-08 13:46 ` Marcelo Tosatti
2013-01-31 9:37 ` Gleb Natapov
2013-02-04 9:11 ` Zhang, Yang Z
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