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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: "Zhang, Yang Z" <yang.z.zhang@intel.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"Zhang, Xiantao" <xiantao.zhang@intel.com>
Subject: Re: [PATCH v6 5/5] KVM : VMX: Use posted interrupt to deliver virtual interrupt
Date: Tue, 19 Mar 2013 12:27:38 -0300	[thread overview]
Message-ID: <20130319152738.GA10627@amt.cnet> (raw)
In-Reply-To: <20130319151955.GC10096@amt.cnet>

On Tue, Mar 19, 2013 at 12:19:55PM -0300, Marcelo Tosatti wrote:
> See the previous argument: should never enter guest mode with PIR ON bit
> set. With logic above:  
> 
> context1				context2                      context3
> 					set_bit(PIR-1)                   
> 					r = pi_test_and_set_on()	set_bit(PIR-40)
> 					set_bit(KVM_REQ_EVENT)
> if (kvm_check_request(KVM_REQ_EVENT)	
>  if (test_and_clear_bit(on))
> 
>    kvm_apic_update_irr()						r = pi_test_and_set_on()
> 
> guest entry with PIR ON=1
> 
> 
> Thats the reason for unconditional clearing on guest entry: it is easy
> to verify its correct. I understand and agree the callback (and VMWRITE)
> is not nice.

Re: KVM_REQ_EVENT setting after set_bit(KVM_REQ_EVENT) assures no guest
entry with PIR ON=1.

Might be, would have to verify. Its trickier though. Maybe add a FIXME:
to the callback and remove it later.


  reply	other threads:[~2013-03-19 15:27 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-15 13:31 [PATCH v6 0/5] KVM: VMX: Add Posted Interrupt supporting Yang Zhang
2013-03-15 13:31 ` [PATCH v6 1/5] KVM: VMX: Enable acknowledge interupt on vmexit Yang Zhang
2013-03-15 13:31 ` [PATCH v6 2/5] KVM: VMX: Register a new IPI for posted interrupt Yang Zhang
2013-03-15 13:31 ` [PATCH v6 3/5] KVM: VMX: Check the posted interrupt capability Yang Zhang
2013-03-15 13:31 ` [PATCH v6 4/5] KVM: VMX: Add the algorithm of deliver posted interrupt Yang Zhang
2013-03-15 13:31 ` [PATCH v6 5/5] KVM : VMX: Use posted interrupt to deliver virtual interrupt Yang Zhang
2013-03-19  8:54   ` Gleb Natapov
2013-03-19 12:11     ` Zhang, Yang Z
2013-03-19 12:23       ` Gleb Natapov
2013-03-19 12:42         ` Zhang, Yang Z
2013-03-19 13:29           ` Gleb Natapov
2013-03-19 13:59             ` Zhang, Yang Z
2013-03-19 14:51               ` Gleb Natapov
2013-03-19 15:12                 ` Gleb Natapov
2013-03-19 15:19                   ` Marcelo Tosatti
2013-03-19 15:27                     ` Marcelo Tosatti [this message]
2013-03-19 16:10                       ` Gleb Natapov
2013-03-20 11:47                         ` Zhang, Yang Z
2013-03-20 11:49                           ` Gleb Natapov
2013-03-20 11:52                             ` Zhang, Yang Z
2013-03-19 15:30                     ` Gleb Natapov
2013-03-19 15:13             ` Marcelo Tosatti
2013-03-19 15:21               ` Gleb Natapov
2013-03-19 15:03         ` Marcelo Tosatti
2013-03-19 15:18           ` Gleb Natapov
2013-03-18  2:49 ` [PATCH v6 0/5] KVM: VMX: Add Posted Interrupt supporting Zhang, Yang Z
2013-03-18  9:16   ` Gleb Natapov
2013-03-18 10:43     ` Zhang, Yang Z
2013-03-18 11:28       ` Gleb Natapov
2013-03-18 11:44         ` Zhang, Yang Z
2013-03-18 22:20 ` Marcelo Tosatti

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